Don't Save the Seals (GTV6 transaxle story)

by Colin Verrilli

Well, the transaxle is out of my GTV6 again. This time the whole thing. Since rebuilding the gearbox and replacing the clutch a couple months ago, I was noticing a smell of transmission fluid (Redline stinks!). I traced the leak to two places:

I decided to fix both because: Since I needed to disconnect the stub axles to get to the rear seals and since I needed to disconnect the driveshaft to get to the front seals, I decided to just take the whole thing out. And I'm glad I did. It's so much easier working on the bench rather than underneath the car. I would recommend it even if you're just doing the gearbox. The outer set of stub axle nuts are usually not too bad (it's the inner ones that can be a bear). The only extra things you need to disconnect are:

Stub Axle Seals

With the unit on the bench, I removed the rotor bolts. I had previously replaced these with the hex/allen type bolts, so removal was not so bad. Loosening the caliper bolts allows removal of the rotors. Four more allen bolts hold on the inner stub axles. They come out as a unit. They are composed of a flange (attached to end of axle), then in order over the axle: shield, oil seal, casing, bearing and lock ring. As you can see, the unit has to be disassembled to get to the oil seal.

R&R of these units is tricky. A bench press is required and special Alfa tools make the job a lot easier. First, the lock ring has to be pressed off. Alfa provides some special plates for this, but a regular press clamp will work. Then the casing/bearing has to be pressed off. For this I used the special alfa plates (different than the one for the lock ring). Now the oil seal and the bearing can be removed from the casing. I replaced both. The bearing/casing/seal piece then needs to be pressed on with a 3rd special alfa tool, but probably a pipe of the proper diameter would work. Finally, the lock ring needs to be heated to 190C (I used a fry daddy with motor oil) and then pressed on with the same pipe/alfa tool. This whole procedure took me about an hour (with special alfa tools available) to do both sides.

Transaxle Front Seals

There are two seals in the clutch/gearbox casing. One is for the mainshaft and one is for the gear selector shaft. To get to these, you first have to remove the clutch front case. There's the four bolts holding the case. The arm on the gearshift selector shaft is probably already off.

Now, you'll be able to see the two seals, but to remove them you need to separate the case and get the shafts out of the way. Drain the fluid. Undo all the bolts. Separate only the front case from the center flange. Now the seals can be removed with a seal puller. The mainshaft bearing can also be removed by first removing one of the circlips. I replaced this too.

I also replaced the pinion shaft support bushing which was badly marked. This required a special Alfa-tool extractor.

Just to be sure I covered all bases, I removed the spring-loaded thing on the side of the case. Some casing sealer between the case and the plate will keep the oil in.

Ending

So the moral of this story is that you should replace all seals when you have the opportunity. Shortcuts will just cost you time later...

The whole thing went back together ok. No more leaks. Just a couple residual problems: an exhaust clunking noise and a driveshaft vibration. The story is never-ending.

Article originally came from here.
 
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