Changing The Tranny Output Seal

Having had problems with shifting and popping out of gear, I found reference to a possible solution, namely synchromesh. Specially formulated for GM manual gearboxes, the glowing reviews of smoother shifts and no embarrassing popping into neutral persuaded me to try it (3 qts. at $4.99 each at Autozone). And it seems to work beautifully, except that now there?s oil all over the engine compartment. At first I suspected a leak around the oilpan, so I pulled and re-sealed it, which didn?t solve the problem but did clean things up enough to locate the cause of the problem, a bad tranny output seal on the right side. I timed it at a drip every 16 seconds, which appears to be about « qt. per day. Autozone had the new seal, $4.99. Having replaced the left one about a year ago, I knew this wouldn?t be too bad, and I already had all the special tools. The whole process took me a little over 3 hours.

1) Put the new seal in the freezer. This will cause it to shrink imperceptibly, just enough to make installation less than a nightmare. Jack the car up and support securely on jackstands.

2) Remove the wheel (19mm), then jam a bar into the lug bolts and remove the hub nut (30mm) and washer.

3) Remove the brake hose to strut bolt (13mm), caliper bolts (T50 torx), disconnect the parking brake cable with pliers and a screwdriver. Remove the caliper and hang it by a wire from the coil spring, so as not to crimp the hoses. Remove the brake disk.

4) Straighten and remove the tie rod cotter pin, then remove the castellated nut (18mm)

5) Break the tie rod loose with a puller, then disconnect tie rod from knuckle.

6) Remove the 3 bearing carrier bolts (18mm), turning the cutout in the hub to allow access to each. Remove the bearing carrier (this may require a puller, I didn’t need it), remove the a-arm ball joint to knuckle nut and bolt with 2 wrenches (15mm) then pry them apart with a pickle fork.

7) Pull the knuckle and strut out and to the rear just enough to wiggle the axle end clear of the knuckle.

8) Open the trunk.

9) If you’re going to re-use it, pull the plug (15mm) and drain the synchromesh oil into a clean container, I used a coffee can, which was near full with 2 « qts. Be sure to replace the plug!

10) Use a pry bar to pry the axle out of the transmission. Remove the axle and clean it if you like.

11) Use a seal puller or pry bar to pull the old seal. I ended up using a prybar. Be careful not to scrape or damage the tranny mating surface.

12) Assembly, essentially the reverse procedure, is easier than disassembly. Wet down the tranny mating surface with some synchromesh, then get your new seal out of the freezer. Start the seal by hand, then drive it in until it seats. Use a block of wood to protect the seal. Lube the seal with synchromesh. Feed the CV axle through the new seal, then push it in firmly till the snap ring catches. Feed the wheel end of the axle back thru the knuckle, replace the bearing carrier with its 3 bolts, and reconnect the ball joint and tie rod. Use a new cotter pin. Replace the rotor, brake caliper, and reconnect the parking brake cable. Put the hub nut and wheel back on. Remove the jack stands.

13) Remove the speedometer VSS sensor by loosening the holddown bolt (10mm), turning the clamp so it is clear, then carefully lift out the VSS. The gear may fall off the spindle, I’?ve had good luck fishing it out with a screwdriver. Put your synchromesh back in, and replace the VSS. Check for leaks before and after driving.

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