AH transaxle teardown questions

Discuss VW transaxles and transmissions. Gearheads wanted!
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jessef7897
Posts: 3
Joined: Sat Feb 20, 2021 12:31 pm

AH transaxle teardown questions

Post by jessef7897 » Sun Mar 07, 2021 4:15 pm

Hello all,
I have some experience with Porsche transaxles but this is my first experience with any VW transaxles. My buddy bought a 70 Beetle from an older gent who had it for years. Along with the car he got a bunch of spares, including two IRS transaxles. They were sitting in the elements for unknown decades. As I am interested in drivetrain work, and having newly bought a home with a garage that allows me to dive into projects, I am taking them apart. My main goal here is experience. I am not rebuilding them with any application in mind, but if they are decent boxes with good components I may try to sell them.

The first one is an AH DSC case with a 8:33 ring and pinion.

I've got the gearset out of the case and cleaned up the majority of the gunk on the case itself. The side covers look decent. There was the remains of fluid in the case, but since it was at least partially outside, some moisture was in there too. There is a spot of corrosion inside the differential housing at the bottom, close to where the non ring side cover mates. It's hard to see in the pic but it has eaten into the magnesium.
case corrosion.jpg
How much of a worry is this? My though was to pick/grind it clean and JB Weld or Devcon the hole, then smooth that out. There is a boss on the outside, I think for a side cover stud. Any chance of the epoxy breaking loose and causing more damage than letting the hole be?

3rd and 4th gears on the main shaft have some rust on the gear teeth. It doesn't seem too bad but it is on the teeth. I haven't gotten 3rd gear off the shaft yet, but 4th gear is off and the side of the gear has some rust and pitting as well. If i am correct these are coarse teeth 3rd and 4th and the dog teeth look pretty good so I would hate to scrap them.
4th rust.jpg
4th rust 2.jpg
3rd rust.jpg
I haven't cleaned the gears thoroughly yet so there is some steel wool debris from me giving them an exploratory scrub.

Any thoughts would be appreciated.

Jesse
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Casting Timmy
Posts: 163
Joined: Sun Nov 17, 2013 9:42 pm

Re: AH transaxle teardown questions

Post by Casting Timmy » Mon Mar 08, 2021 8:10 pm

The case doesn't look so bad, reuse it if you have too. Lightly hit off the high spots of it, if you keep brushing it just goes deeper and deeper.

Press off the hubs on the gears and then wire wheel them to get them cleaned up and inspect them from there. I think they'd be worth cleaning and inspecting, my guess is they'll clean up fine.

Future notes is that some grade their parts and use them for different applications. I'm guessing those should clean up pretty good, but pitting or visual staining left after cleaning could make them have a little extra noise. Pits that are black are usually a material failure happening and good for paperweights or making transaxle tools.

jessef7897
Posts: 3
Joined: Sat Feb 20, 2021 12:31 pm

Re: AH transaxle teardown questions

Post by jessef7897 » Wed Mar 10, 2021 7:26 am

Thanks for the reply.

When you say press the hubs off of the gears, I am confused. Are you calling the hubs the part with the dog teeth? There is that tin shim-like piece between the gear and the dog teeth. Can I separate those pieces?

I got 3rd off the main shaft and cleaned everything up. There is some rust on the mainshaft and other gears as well so I'll take the wire wheel to them and see how they come out. I'm not too worried about noise at the moment, more metal failure like you mentioned.

Bruce2
Posts: 7036
Joined: Sat Oct 13, 2001 3:01 am

Re: AH transaxle teardown questions

Post by Bruce2 » Sun Mar 14, 2021 2:58 pm

jessef7897 wrote:
Wed Mar 10, 2021 7:26 am
Are you calling the hubs the part with the dog teeth? There is that tin shim-like piece between the gear and the dog teeth. Can I separate those pieces?
Yes, the synchro hub is just a press fit onto the gear.

Is there rust on the bearing surface of the main shaft? What about the ID of the gears?

You can also bead blast all the gears to get the rust off.

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