Engine/Transmission (1998.5 - 2002) Transmission jumps out of third gear

[JPulliam]

Recently my transmission (NV4500) started jumping out of third gear on acceleration. I can hold it in gear, which keeps it from jumping out. It is getting progressively worse, and I want to take care of the problem before I have a catastrophic failure. Daily driver you know! What could be causing this, and what do I need to do about it?

 

[JPulliam]

Huh, I figured this would have happened to others. Another update. Coming home today I could barely get it out of fifth, and could not shift into fourth. I finally got it back into fifth, and fourth but it was very hard to shift. Sitting still it is hard to get in third, fourth, and fifth. IT WILL NOT GO INTO REVERSE AT ALL. It feels like it does when you try to shift from fifth to reverse. The shifter just slides down and left of reverse. Got any ideas so I know what I am getting into?

 

[BEmmert]

When my 98. 5 started having the same symptoms it was a bad clutch/throwout bearing bushing of the sorts. 3rd never came out, but the other symptoms were the same.

 

[JPulliam]

It won't even shift decent(like it used to) with the engine off. After pulling the inspection covers I see the magnets are hairy scary! No chunks, but lot of shavings.

 

[JPulliam]

I got the trans out and decided to pull the top cover and tail housing to see if I could locate the source of this problem. When I pulled the tail housing I could see that two bolt heads were missing from the main shaft rear bearing retainer plate. Huh! Found one bolt head and two washers in the main case, and the other head fell out of the tail housing when removed. Nothing appears damaged, so I'm going to replace those bolts and see if it will shift on the bench. If so I'm gonna put it back in and see if my problems are solved. There was a lot of play in the main shaft assembly with that retainer plate loose. Anyone know what size and thread pitch the bolts are?

 

[JPulliam]

Bolt size is 5/16-18 x 2"