While this article was originally written for Fiero 1987-88 L4, it applies to all vehicles with self tensioning serpent belt systems.
WARNING: Do not assume that the belt listed in the catalog fits your engine! If the belt forces the tension assembly out of range you can and likely will break things.
WARNING: NEVER force the tension assembly! If you don’t break it instantly, it probably won’t last long. Most tension assemblies have internal stops. IF the tension assembly is actually binding, replace it ASAP or you will find yourself stranded someplace, likely someplace nasty, in the near future.
DO NOT start a car that shows the tension assembly out of range! You will not be able to exchange the belt once you run it even a few turns. Running the belt WILL NOT make it fit. (You also want your hands and the pulleys clean as most stores won’t exchange a filthy item.)
As many of you may have noticed the serpent belt setup used in the 87-88 4 cylinder cars is not well covered in the Haynes or Chilton’s books. (At least not that I’ve ever found it.) The belt is easy to deal with as long as you keep a few things in mind.
The Fiero 4 cylinder Serpent belt requires no adjustment. Belt tension is controlled by a spring-loaded arm.
The one tool you should have is a “serpent belt wrench.” You can do without this tool but it usually means yanking the battery to get enough room to rotate a socket wrench. The belt wrench is made to fit into the confined space in Fiero and other such cramped cars. It’s worth the extra cash. ($15-30 US, shop around.) These are cheap enough that you can bend them for a custom fit to a given car, tho I think you will have to heat them to bend them.
To unload the belt tensioning arm put a 15mm wrench on the Idler Pulley bolt and rotate the wrench toward the battery. NEVER attempt to remove or rotate the bolt in the center of the spring arm!

Things to remember about serpent belts.
(Applies to all cars with serpents.)

• When properly tensioned Serpent sets will always out perform V-belts. This is why nearly all Serpent sets use a spring tensioning device. (See note at bottom.) It is critical the belt tensioning device work properly or belt life will be shortened tremendously. Because Serpent sets are carefully calibrated, life of PTO devices is also improved. The alternator, water pump, etc, are all protected from running with an over tightened or loose belt, which protects the bearings and sheaves from excess wear.
• These belts HATE oil grease and coolant. You’ll eat one up in short order if you get one contaminated and don’t clean it off. If for example you spill oil during an oil change and it gets on the belt or a pulley you must clean it up. To fully clean it up take off the belt and wash everything in citrus base cleaner or Simple Green. NEVER use parts washer or other solvent on the belt. (Brake Parts Cleaner will work well on the pulleys.) If you don’t get this mess cleaned up then the belt will glaze and start squealing. Once the belt squeals it must be replaced.
• Make sure the belt is running centered on the Idler pulley. In Fiero this is the smooth pulley that runs on the backside of the belt. If the belt is running off the edge of this pulley then the spring arm has likely gone bad and will have to be replaced. The spring arm cannot be serviced. (Only the bearing in the idler pulley can be replaced.)
• On some cars the Idler may be grooved and other pulleys may be smooth. All the pulleys must line up or you’ll eat belts. (The FWD applications of the 2.5 often have a smooth water pump pulley.) The belt must never be allowed to run off the edge of a pulley.
• Whenever the belt is off carefully check the bearings in the idler pulley, water pump, and alternator. (If present check the AC compressor.) If the bearings are sloppy, rumble, or feel “dry” as you turn the shaft then you have other problems besides the belt wearing.
• When installing the belt it helps to have someone under the car to hold it on the crankshaft and AC pulleys. These are hard to see and new belts tend to have a mind of their own about staying on them.
• On Fiero L4 and some others… Slip the belt over the smooth tension pulley last. Let the belt lay between the pulley and the wrench until it is around all the gooved pulleys.
• Keep an emergency belt and the wrench in the car at all times. For an emergency belt I recommend using the belt for cars without AC, even if the car really does have AC. This belt is easier for one person get on from the top with the least amount of mess. It will also give you backup if/when the AC compressor fails and cooks off the belt. (With the age of most AC compressors the chance of this is pretty high.) You can drive a car w/o AC but not a water pump or alternator. (It depends on the car. Fiero 4 cyl’s can be run with either the AC or non AC belt. Some cars can’t do that trick.)

Side note: Some cars use serpent belts in place of V belts, and also tension them the same way by adjusting either the Alternator or AC compressor. It is critical that these applications be correctly adjusted or the belts will not last.
Serpent belt material is much more picky about tension that V belts.

Belt Map

For those people that don’t have the belt map on the deck lid…

Why Does My Belt Keep Failing?

The first thing to check is pulley alignment and operation of the tensioning device. A critical factor here is that pulleys that are close together tollerate much less alignment error than pulleys far appart. An AC equiped Fiero will eat belts very fast if the crank, AC and Waterpump pulleys are just a little off. A non AC Fiero can take a more error as all the pulleys have longer belt runs.
Make sure every pulley is clean. Make sure nothing is packed into the grooves or built up on the peaks. Packed dirt will make problems.
Is oil or coolant getting on the belt? That will kill it fast.
How are you cleaning the car? Some cleaning and most wax products are bad for the belt. Fiero’s vent grates allow such products to easily find their way onto the belt. It wouldn’t be a bad idea to throw a cover over that side of the engine to prevent car wash products from getting on the belt. (Make sure the cover can’t contact hot exhaust parts! Remove the cover as soon as you are done washing!)
Check the AC compressor! If there is any missing or loose hardware, the compressor will move and alter the pulley alignment. Any alignment error will greatly shorten belt life but it is even worse with a high load item like the AC.
The belt’s life will be affected by the high heat in the engine bay. Depending on the setup of the vent grates, and a few other things, the belt may not last more than a year or two even if everything else is perfect. My experience, even with Fiero’s hot engine bay, is that the belts will last several years unless the pulleys have problems.

Checking Belt Tension

This works for most spring tensioners and will check your belt length as well without measuring anything.

• On the big round end of the arm where the pivot and spring are, there is a small arrow. It is hard to see and is often just a small triangle.
• On the arm mount, there is a gauge area. This often looks like V*******V or it may be a simple raised/indented bar on the metal. It can be hard to make out too.

Both marks are usually on the top part of the tensioner’s pivot area and shouldn’t be hard to find
once you clean the dirt off.
The image left shows the actual scale on an 87-88 Fiero L4 tensioner assembly. A new belt should have the pointer on/between the closer marks. (These marks will be slightly toward the front of the car on top of the tension assembly. The bolt hole you see is by the water pump.)
The pointer on the arm must be within the gauge area on the bracket. If the pointer is not in that area, the belt is not at the right tension and probably will not last long. Ideally the pointer should be in the middle of the gauge. If it is right at the low limit, the left end of the scale in the image, then it will probably move out of range as soon as the belt wears in some. Frankly If the belt is even close to the low limit, you want to replace it. Either it is very worn or significantly too long.

This belt doesn’t fit, the Catalog must be wrong…
If you can’t get the catalog belts on a car with a spring tension setup, you could have a few things besides a wrong belt. For the 87+ Fiery L4 here are some of the most common listings:

• Fiero 2.5L with AC: K060660 (Gates) 660K6 (Drive-Rite) 5060660 (Dayco) 4060660 (Goodyear)
• Fiero 2.5L no AC: K060615 (Gates) 610K6 (Drive-Rite) 5060610 (Dayco) 4060615 (Goodyear)

The Gates Goodyear and Dayco numbers are direct from their online catalogs.
Drive-Rite, a Dayco brand, is from PartsAmerica.com Oddly the Drive-Rite and Dayco cross references to Gates K060612, which is .29 inch shorter than K060615.
There is some tolerance in the system for variations in length. As long as the tensioner stays in the proper range, it doesn’t matter if one catalog says a hair longer/shorter than another. If you put a belt on that is at the bottom limit new, it could get out of spec once it runs in so make sure you check it after a few hours running.
Warning: The belt should easily slip onto the Idler Pulley on the Tension Assembly.
You should never have to fight a belt onto the idler. (Or whatever pulley goes last on other engines.) At the same time when you let off the idler, the idler should keep it tight. (Duh.) The range of acceptable belts is fairly small.
If the listed belts won’t fit, the first thing to check is the number printed on the belt. It’s not uncommon to have the belts get in the wrong package. The sleeve packing many companies use can fall off and sometimes the parts store or distributor puts the wrong belt back in the thing.
If you got the listed belt ok then you could have a bad belt tension device.
These often bind up with age and you may not be able to move them far enough to mount the belt. Don’t use a longer belt to get around this. The longer belt probably won’t be tight enough and could fail really fast. Go by the scale on the tension assembly! If the pointer is off scale the belt is too short regardless of catalog listing.
You could also have a replacement alternator or other device with the wrong size pulley. This is very common and why you need to check the pulleys on replacement parts. A small change in any one pulley can result in a belt change of an inch or more depending on the pulley size and how much belt wrap it has.
If a pulley has changed, it could cause you other problems. If the alternator is spinning too fast or slow there can be trouble. (Read Watt Story for more on that.)
There is some variation between how belts sit on the pulleys. This can be from one brand/type to another or even from one batch to another.
You may also suffer from “tolerance stacking.” In this case slight variations in mounting of the driven devices can require a slightly longer or shorter belt on the system. The alternator, AC compressor, waterpump and so on have some slop in their mounts. Over time and various parts replacements these parts may be in slightly different locations than original. These changes can add up in ways that make the belt path longer or shorter than the vehicle maker called for. The catalogs all list only what the vehicle maker said fits.

How serious is correct belt fit?

If you want to avoid this…

Make bloody sure that the tension assembly’s pointer is on the scale. Most if not all tension assemblies will not tolerate being pulled over range. If the pointer goes off scale low, the belt can go completely slack and be thrown from the engine.
To be more annoying… You won’t know until you try a given belt. There is enough variation that a 66 inch belt from one maker will sit a little differently and be ok while another doesn’t fit. Belt route will also be a factor. Bypassing the AC on the Fiero L4 can make it so all the 61 inch belts fit even when you have problems with some 66 inch belts.

How do I read a belt size?

The last or first three digits of the belt size tell you how long it is in inches and tenths. A 660K6 or x060660 (x varies by brand/type and isn’t very important.) is 66.0 inches long. The next two sizes larger are 665 and 670. 66.5 and 67.0 inches. (In my case the 670 belt has the pointer just a hair above the “middle” mark on the scale.)
An important note… The sizes that end in 5 are not always exactly .5 inch.
Dayco 5060665 is actually 66.6 inches according to Dayco. That means you need to check belt specifications.

Tension Assembly Replacement

Replacement assemblies should come with a gasket on the engine side. If the gasket is missing, you will have to make one. The gasket needs to be 3/32 inch thick. RTV Silicone WILL NOT work in this application!

1. Drain the cooling system. (The arm unit forms a cover on the front of the water jacket.)
2. Disconnect the battery and remove it.
3. Remove the top alternator bolt. (You may want to loosen the bottom one, the new tensioner may not line up exactly.)
4. Remove the Idler Pulley from the old and new tension assemblies.
5. Remove the old tension assembly and install the new one.
6. Replace the Idler Pulley on the new Tension Assembly.

If the new arm comes with a cork gasket then paint the gasket with Permatex High Tack, Permatex Super 300, or Balkamp Aviation sealer. This will fill any pours in the cork. A VERY THIN film of RTV Silicone will work if that is all you have handy. Make sure the whole area of the block covered by the arm base is clean before installing the new arm. If you pinch something between the arm and block you will likely damage the new arm or prevent it from sealing.
The new arm provided by Pontiac is built a little better than the original one.
You should only have to replace the part once in the life of the engine. (Keep in mind, because this arm is a cover on the water jacket it is exposed to full operational heat of the coolant. The old grease in the arm didn’t hold up well, and that results in pivot wear.)

Why Is There a Hole In My Block?

The large hole in the 4 cylinder that is covered by the serpent tensioning device is the opening for the water pump when this block is used in other vehicles. In most FWD versions, the hole has a steel cover bolted over it. The only variation I’ve seen use the hole is the S-10 truck. (I’m not sure if S-10 is exactly the same block or not.)

Since I had to replace the other one recently, I figured it was time to revisit this article.
The Constant Velocity shafts in Fiero aren’t very difficult to work on but it certainly helps to know a few tricks.

Axle Nut

WARNING: The axle nut will need to be turned with a wrench for all but the tip of the axle shaft and can get quite hot while spinning. Be careful handling the nut and the socket. The nut can burn you. The socket may get uncomfortably warm.
The 30mm locknut used on Fiero drive axles is intended to be a single use item. It should be replaced each time it’s removed. The nut isn’t likely to fall off. The axle can’t come out even if it did, but if the nut comes loose you can out wear the hub and axle splines in no time. At that point you’ll need a new hub and axle… (An axle with spline damage may not be accepted for core… That could cost you from $20-50 above the normal cost of the axle.) I strongly recommend a new nut any time the thing is off. It’s cheap insurance. ($3.00-$5.00) The nut is available at most parts stores. I won’t reuse one more than a couple times. This nut wears considerably when you work with it and the heat of remove/replace messes with the hardness of the nut. If you get a single click noise as you brake or accelerate then this nut may not be tight enough.

(Torque spec source: Axle, Haynes Fiero repair book 79008. Lugs, Raybestos.)
Note: A note in the forums indicates the correct torque is actually 170 ft-lbs for a used nut. This makes more sense. It’s been my experience that a used nut will need more than 70ft-lbs torque or the axle will do the single click thing. To reach 200ft-lbs you’ll need to be very strong or use about 3 feet of handle on the socket.
You really want the wheel on to remove and replace the nut. The suspension bounce can make it very difficult to tighten the nut. You could even knock the car off the jacks trying to do it with the wheel off. You’ll get the best results if the car is on the ground with someone holding the brakes while you tighten the nut. Use the spare tire if Aluminum wheels don’t have enough room to let the socket in.

Axle Removal

Trick One

There are a few ways to get the axle out. I prefer this one.
· Unfasten the brake line from the strut.
· Unfasten the brake caliper from its mount and tie it up so it’s not dangling from the cable or hose.
· Remove the pinch bolt from the ball joint.
· Separate the ball joint.
The whole assembly can now be swung out to clear the end of the axle without messing with the tie rod.
If you push in on the axle, you’ll compress the inner CV and gain additional clearance.
Some people prefer to reverse this a bit. They leave the brake caliper attached and separate the tie rod. If you do this be very careful you don’t damage the hand brake cable or the brake hose.

Trick Two

Note… The axle often lets go easier if you can give the thing a quick pop instead of just prying on it.
A clip inside the transmission holds the axle. This can make extracting the axle a pain.
With stubborn axles, it may easier to pop the axle if you use 2 pry bars. Using 2 bars allows you to get an even load on the axle. The clip isn’t that strong but the thing usually exits the transmission easier if the axle is pried straight. Be careful where and how you pry on the transmission case. Avoid creating spot loads on the case. Some areas can crack very easily if you pry directly on them. Use blocks of wood as needed to prevent this. When using 2 pry bars, this can be tricky. Tape the block to the bar so you don’t have to hold 4 things at once. Yes, there is at least one tool for this… The one I’ve seen is a 2-armed thing that connects to a slide hammer. Most people don’t do this often enough to need the tool.

Seals

Always replace the seal in the transmission anytime the axle is replaced! If the seal is old, it’s better to replace it even if you are reusing the same axles. Better to do it now than risk a leak after… If you score the mounting hole for the seal, clean the hole with brake parts cleaner and then apply a thin coat of sealer. For most scratches I like a paint type sealer like Permatex Super 300 or Balkamp Aviation sealer. If it’s a deep scratch then you may have to use RTV Silicone. Don’t get sloppy with the Silicone! A little bit goes a long way for this use. Rodney carries a combination seal and bearing that replaces the original style seal. I’ve yet to use them but everyone in the forums who has seems to like
them. (He also has replacement seals for his bearing sets. Now if you wreck a seal you won’t have to replace the whole bearing.)

Removing

Removing a seal often is no fun. The left seal is the worst. For the right axle, you can often just pry it out. But be careful not to damage anything. If it gives you trouble, then collapse the seal. To start, remove the collar that protects the rubber seal. It’s pressed into the seal. The metal is soft, you should be able to cave the side in then pop it out. Then you’ll be able to collapse the side of the seal and pull it out. Trust me… taking the collar out makes the seal much easier to remove. For the left side on the automatic… there is only one spot I found where you could get a bite on the seal with the thing in the car. Unfasten the mud skirt and go at it with a long screwdriver from the back. The screwdriver will be against the cradle as far back as you can get it. Tap lightly until the seal quits. Don’t pound it or you could chip/crack the case. It helps some if you collapse the inner part of the seal, where the rubber is held, and then cave in the outer part.

Installing

Driving the seals is a pain. The best driver I’ve used for these is a section of 2″ Schedule 40 PCV pipe. A regular driver, like the one from Lisle, worked ok on the right seal but won’t work for the left axle at all. You have to use pipe or a special tool for that one because the transmission shaft protrudes thru the seal. The PCV pipe fit these seals very nicely and won’t damage the guard. If you can’t get a perfectly straight shot at the seal don’t worry either… Just cut the end of the pipe at a slight angle. If you have a 2-3 pound mini sledge (AKA Drilling Hammer) use the side of the head. If you only have a small hammer, use a block of wood to spread the impact.

Selecting Replacement Axles

When buying new/rebuilt axles, it’s fairly common to have the wrong axle in a box! Lay the 2 shafts side by side and make sure they match before turning in the core. (Yes, I have had this happen. Extremely annoying.) Make sure new/rebuilt axles are the same length as the old ones! Never install an axle that is the wrong length. Too long and you could bind the inner CV. Too short and the inner CV will likely be torn apart. (This may not happen until you go over a large bump.) Also check outer CV profile. It must match the original. That means it has to accept the guard ring as well as fit the seal and hub. Don’t worry if the CV boots are a different type as long as everything else is correct. In fact, when you can find them, you want the ones with driven on neoprene outer boots. They are better boots and clear the hand brake cable much better than the thermoplastic ones that are clamped at both ends. There should be a metal guard on the outer CV that is just lightly pressed into place. This piece may need to be transferred to replacement axles. That guard protects the hub seal from dirt and so on. Try not to mangle it when you move it. It is better to work it off with a bunch of light tapping than try to get it off in a couple shots. No, you can’t use an axle from an automatic in a stick or the other way around. They won’t fit.

Extending CV life

There’s not much you can do that will affect the CV’s but this might help. Unless you live where speed bumps are common… Fiero outer CV joints spend nearly all of their time operating in over a small angle. If you give the wheels a few spins anytime the car is up on jacks it may help move the grease around in there. It might not help much but it sure won’t hurt anything. When you do this, listen for noises and feel for any inaudible pops that may be early signs of CV failure.

Axles for other transmissions

There have been many threads in the forums about this. Use the search function and search for axles to find the others.

Hub units

The hub isn’t hard to change. Again, anytime the axle is loose you should use a new axle nut.
One important note about buying hubs… the 84-87 hubs should come with a new seal loose in the box. This seal is driven into the knuckle to seal the axle. It provides additional protection for the hub cavity in the knuckle. Make sure the seal is in the box with the new hub. I don’t think you can get it separately. (Most hub units come with this seal.) These hubs should also come with a large O ring, usually it’s on the hub, that seals the front of the cavity in the knuckle. These seals are to prevent the hub from rusting solid in the knuckle. (The cavity isn’t totally sealed. There is a drain hole below the axle seal.) Before you knock the old one out the back, make note of its position and orientation. The new seal must be installed the same way. The new seal is driven in from the front (hub) side. I strongly recommend a seal driver for this. You’ll want the control the driver gives you to keep the seal straight.
Don’t forget to grease the seal before installing the axle. I also coat the inside of the knuckle hole with grease to prevent rust. You don’t need to gob it in, just coat things.
I haven’t been able to find a torque specification for the three bolts that hold the hub to the knuckle. Since they are the same size as the wheel lugs I ran them to 90-100 ft-lbs. I took a couple passes around to make sure I didn’t warp anything.

Driving the axle seal

Use of a regular seal driver will force you to remove the axle to do the job.
There is another way…
Measure the depth of the seal in the knuckle! The new seal has to be driven to the same depth. The axle usually has enough slack to push back out of the seal enough to work. Knock the seal out the back of the knuckle, bend/squash it out of round and then pull it out the front.
To drive the new seal…
Get a section of 2″ ID Schedule 40 PVC pipe and a straight connector. Glue the connector to the pipe. Use the connector end to drive the seal. A large hammer works better than a small one. Not because you need to beat the seal but because the big head spreads the load over the end of the pipe. I use a 3# mini sledge turned sideways for this.

You should grease the splines a little to prevent them rusting into the hub but don’t grease the areas shown above. You should also grease the axle seal to prevent wear.

The Fiero TCC
(Transmission Solenoid Lockup)

by Chuck Kichline

http://www.kichline.com/chuck/fiero/TCC.htm
7/10/2008

I found out that there wasn’t a lot of information on automatic transmissions for the Fiero on the web, and even worse, both the Haynes and Clymer manuals are weak on diagnosis and had NO information on repair.  It became very important to me when my Fiero started staying locked up, stalling the car in traffic and endangering my LIFE!  Since the commercial manuals are no help at all, I started a search on the web, and finally found the information I was looking for.  Here is what I learned..

What is the lockup solenoid?  It’s an electrically operated valve in your Fiero automatic transmission that is controlled by the car’s computer.  When the computer believes it would be effective to lock the torque converter up solid it powers the solenoid which makes the transmission lock up.  The effect is that “fourth” gear that you sometimes feel on what is really a three speed automatic transmission.  The effect is better gas mileage, as it reduces the speed of the engine by about 250 RPM when it cuts in.  Not a whole lot, but good for a couple of miles per gallon.

What can go wrong?  Like all the other electronics on these cars, they can fail.  The failure may be that the lockup doesn’t happen, or that the engine stays locked up when coming to a halt, or blowing fuses.  If the lockup doesn’t happen it can mean poor gas mileage (18-19 mpg in a V6), the engine revving faster than it should, and possibly running warm or even overheating. Blowing fuses gets you the same result, since the lockup doesn’t work. Having the lockup stick on can be very dangerous, and leave you stranded in traffic in a car that won’t go into gear – or won’t properly kick down to pass.

How can I tell if my lockup isn’t working?  Do you occasionally feel what feels like a fourth gear?  Then it’s working.  If you want to test it, take the car up to about 55 on a level road, and press lightly on the brake pedal.  It should disengage the lockup, and with a steady foot on the gas, you should see the tachometer move up by about 250 RPM just as the brake lights go on. Another hint is that when coasting down from speed, it should disengage at 45mph – it feels like the car is speeding up on coast down, because when it disengages, the car starts freewheeling.

How can I tell if it’s sticking?  I had that fault, and it feels just like you forgot to put in the clutch in a manual transmission as you pull up to a stop light. The car stalls, if you’re lucky it will unstick and when you restart the engine. If you are unlucky like me, you’ll be stuck in the slow lane of the freeway with a car that will not move!  I finally got it out of traffic by revving the engine and slamming it into gear, and got out of the way in five foot jumps.  Not a good thing.  It had done it a few times before, but had always healed itself after the car died.  The previous owner had mentioned having some transmission work done, a “shift kit” (after I bought the car) and my guess is that she had had the work done only to find out that it still had the problem.  I guess that’s a good thing – otherwise she’d still probably be driving her car! What do I do if I have a problem?  If it isn’t locking up you are working your car harder than you should, higher revs and more heat.  You ought to fix it.  If it’s locking up and staying locked up, I suggest unplugging the lockup connector – that’s the green connector on the left front of the transmission “bell housing” behind the engine.  That will make it NOT lockup ever, and puts you in the no lockup mode.  It’s probably safer than getting caught in traffic and not being able to drive home!  If the transmission is locked up, the problem is probably in the solenoid being physically stuck or plugged, so just unplugging the connector while the engine is locked up doesn’t help, but it will keep it from happening again.

I risked trying the repair.  It turned out to be relatively easy, and I bet saved me several hundred dollars.  This is what I know, maybe you can do it too?

The lockup solenoid is under the cover on the left SIDE of the transmission. First we need to remove the cover.  From the top of the car remove the carb/aircleaner tube, the bolt that holds the transmission cooler hose (first arrow) and all of the bolts that hold the side transmission cover that you can reach from here (second arrow).

Here’s the solenoid connector that I mentioned earlier.  You don’t have to unplug it now if you haven’t.  See that the other stuff is now out of the way. Now jack up the car and pull the left rear wheel.  Put the car on a jack stand.

Remove the “tar paper” skirting between the inner fender and the frame.  It’s mounted mostly with reusable plastic pop rivets, just pull out the centers and put them back together to reassemble it with later. Tuck the skirting over to the side as you can.  Here’s the side cover from the wheel well. Looking down on the valve body after removing the side cover.  There should be just a little ATF in the side cover, so be ready to catch it when you take the cover off.  Pull the cover out the top.

OK,  here’s the valve body from the side.  The two wires come from the lockup connector.  Here’s the theory – there are TWO components in line. First the lockup solenoid then a pressure switch.  When the computer turns on the circuit it should close the lockup solenoid and the transmission should lock up.  In line with the lockup solenoid there is a pressure switch that is normally open, if the computer tries to lock up the transmission but there is not enough pressure the pressure switch is open and it doesn’t lock up – a mechanical interface to the transmission.

Those are the parts that I have highlighted.  If the transmission stays locked up, the problem is most certainly the solenoid and it should be replaced.  If it doesn’t lock up it could be either the solenoid or pressure switch.  Replace them both.  If it’s shorting, it could be either solenoid, switch or wires, check them all.  You may want to replace everything anyway, since it’s already apart. These parts are NOT going to be available from an auto parts store.  You will have to go to a transmission shop or dealer to get them.  I went to a transmission shop and was treated REALLY fairly.  You’re looking for the “transmission lockup (tcc) solenoid, pressure switch, and side cover gasket”. Ready for the cost?  About $20 for the solenoid, about $10 for the switch, and about $5 for the gasket.  YOUR PERFORMANCE MAY VARY!  Take the

side cover so they know for sure what transmission you have.  They’ll probably have to order the parts so go home and clean things up. I see that The Fiero Store stocks the solenoid now;  convenient, but at twice the price.

Here’s the inside of the cover – ready for cleaning.  Don’t forget to clean the old gasket off the cover and transmission body.

Here’s the solenoid out and sitting on the frame rail.  It’s held in by ONE T30 star screw.  I’d always used just a hex wrench before on these things, but it didn’t want to come loose so I bought a 3/8″ drive set with about seven different sizes.  It cost about $15 and those star screws are all over GM cars anyway.  It came out easy. Pull it down out of the valve body.  The pressure switch is a big hex, you may have to buy an “oil sender” type socket to remove it – it unscrews.

Here’s a real bad picture of the solenoid kit I used.  You cut the wires on the old solenoid and then use the quickie splices to install it.  The positive side of the solenoid goes to the wire directly to the lockup connector (and the negative goes to the pressure switch).  I’ve been told that the OEM solenoid comes with the wiring harness and connector.

Then you just put EVERYTHING back together.

So here it is all back together again.  I can say that I fixed my automatic transmission and it was relatively EASY!  Actual work time was only four or five hours.  I suggest that you change the fluid and filter now.  About six months after I fixed my TCC the transmission started slipping, but was fixed by changing the filter and fluid again (it had been changed before I replaced the TCC).  My guess is that the random lockup had kicked a lot of clutch plate parts into the fluid and they plugged up the filter.

I’d like to thank everybody that helped me, and hope that this helps others.

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