Ouch... that bearing is toasted! I like Kary's method for pulling the bearing. I would have spent way to much time making a puller to do the same thing.

Spot on that most bearing failures are caused by contamination and a gear box is a nasty place since the gears are goint to spit out metal. The worst time is when the gears are new and the teeth need to burnish in.

You can get a sealed bearing for the 4 cyl tranny input shaft. That is the first V6 unit I have seen and I am impressed that they went to seals on most of the bearings.

If I remember right the original 4 cyl mits trans used ball bearings on the counter shaft. I am sure the bearings were smaller than those used on the V6 unit and they did fail pretty fast if you used one behind a turbo 2.6. 12,000 miles was about as long as i ever got.

Good luck,

Kevin

so what your saying is that this tranny isnt going to last long with this turbo engine going in my truck even if I rebuild it with new bearings?

Yours should be one of the improved models with tapered rollers on the counter shaft. The ones I had trouble with were in my 1978 Plymouth fire Arrow.

Those units used a cable operated clutch and a slighlty differant case. I needed to add a hydralic operated clutch to use the stronger transmission.

Kevin

That could be part of the problem <img src="/forums/images/graemlins/lol.gif" alt="" />

No, I installed a junkyard transmission last year. I just now got around to dismantling the failed transmission to see what went wrong.

I fixed the front windshield wipers (I cut a piece out of a junkyard truck and had it welded in).

Is this the bearing that is talked about as being upgradeable from an 88-89 Quest tranny?

haha ya think? I am just afraid of how long this tranny that I have in there now, which was a junk yard replace ment with 104k on it, will last with this turbo motor going in. I am hoping a rebuld of the broken one will not cost too much, I would like to do that this winter when im home on christmas break

Two questions:

-Any idea why the one bearing didn't have seals when the other three did? (I didn't see any evidence the trans had ever been apart and didn't find any seal "fragments").

-How does the gear oil get to the bearings that do have the seals? Does enough seep around the rubber to keep them lubricated?

Jim;
My '89' manual shows that bearing as being open also and the rest of them do seem to have seals.
Yes, the lube has no trouble getting into the bearing, but the chunks will hopefully not get in there.

This is a common set-up in the industry, in Suv/trucks anyway. I've never seen it on a Porsche/VW/Audi/Ferrari/BMW/Lambo/Maser trans though. maybe less chunks, or better drivers less miss shifts, or ...........??
Kary

Did they improve this bearing in the VMT51-2? Is that the difference??

Do you recommend replacing the rear counershaft bearing too, as it has had that twist placed on it and carries the load of tose same gears all the time?

And , are these bearing available aftermarket or Mitsu only?