Can't get transmission apart

[steve91tt]

I'm in the process of rebuilding a 2nd generation 4-speed transmission and I can't seem to get the case apart. All the bolts inside the bell housing and from the center section came off easily as did the pin in the rear section, the speedometer tap and the various plugs.

I can't seem to get either the plate inside the bell housing or the case to separate. Am I missing something? Has anyone else had this issue?

[zKars]

The FSM has a very detailed description of what to remove in what order to dis-assemble the 2nd gen 4 speed. (look at any FSM for 72 or later). Page TM-3 in the 73 manual is what I'm looking at.

There is a "main drive bearing snap ring" as seen from inside the bell housing that's retaining the front bearing that may be the big thing you forgot. They also mention the back up switch, C-ring and pin, and return spring plug and what's found inside on the rear extension that have to come out to get the back half off. THere is pictures of everything. xenons30.com has the FSM's on line.

[Zed Head]

The snap ring catches people sometimes as zKars says. The snap ring is external to the bearing, in a groove on the outside of the bearing race, keeping the bearing in the case, and the circlip keeps the bearing on the shaft. If you just take the the circlip off, you'll be trying to pull the interference fit bearing off of the shaft. I've only taken one trans apart, but that's what I did, the bearing ends up in the front case. It's a slip fit in the case though, so it will come right out when the snap ring is removed.

I've also seen a few accounts where people couldn't get the back half off (like you're describing) without using a dead-blow hammer or a block of wood on the ears of the back case (tail-shaft housing). It needs some shocking in the right direction to get moving.

[beermanpete]

We had to remove the clutch release arm pivot ball from the front plate and install a screw in its place to push off the front plate. Once the front plate is off you can remove the snap ring mentioned above. After you remove all the external parts, as mentioned above, and in the manual, you can separate the main case from the adapter plate. This may require a soft faced mallet and some good, hard blows to brake the sealant bond loose.

[steve91tt]

I have been following the FSM and all of the external hardward that you describe is off. I haven't been able to get to the bearing snap ring because I can't get the bearing cover to budge. I've been hitting it through the clutch shift fork hole in the bell housing but I've only managed to ding up the side of the plate. I'll try the bolt in the pivot ball location trick to see if I can get it to move. After that I guess I'll start beating on the case with a deadblow and block of wood to get it to let go.

[Zed Head]

Without either the circlip or snap ring off, the front half of the case is locked on to the shaft by the main shaft bearing. Heat around the edges of the front cover along with some PB Blaster or similar will soften up the gasket material. I think that the back half should still come off though, not sure what's happening there. I actually had problems keeping the back half on when all I wanted to remove was the front half (bellhousing).

Edit - also just realized that I've actually taken three transmissions apart, two partially, one completely. For what it's worth...

Edited April 30, 2012 by Zed Head

[steve91tt]

Thanks Zed Head. I think that this trans has been rebuilt before and assembled with some sort of glue on the gasket material. I've never taken one entirely apart but I've taken the front cover off of my other transmission with no issue at all. This one is very different.

[steve91tt]

The bolt through the pivot ball trick worked like a charm on the front cover. I then threaded an extra long bolt into the center section and beat on it with a dead blow hammer and a block of wood. It finally came apart. There was no gasket material between the sections. Just some sort of glue. Everything looks new inside. I may not replace the syncros but I will do the bearings while I have it apart.

[beermanpete]

Hurray! Nothing like a BFH to deal with the tough problems.

There are no gaskets on the case to adapter plate. Sealer only. The bearing clearances are to critical to allow for the vagueries of gasket thickness.