I've got an '86 Trooper 4X4 5-speed that started making what I believe is a transmission noise yesterday after driving for a few hours. It sounds like metal scraping or squeaking and is very loud even outside the vehicle. It only happens when the transmission is in gear and when the vehicle is moving; the odd thing is that it doesn't make the noise in 4th gear. Any ideas?

Thanks, Tim

The transmission is arranged in such a way that one shaft (input) uses gears to connect to an intermediate shaft then gears drive the output shaft to the transfercase and driveshaft. 4th gear is 1:1 ratio which does not use the gearing of the intermediate shaft. I have read that a transmission noise that shuts up in 4th gear is typical of input bearing excessive wear due to lack of oil.

I forget the specifics as to why the noise quiets in 4th gear, something about a load not placed on the bearing as its supported by other bearings or something.

My trans had this problem when a related problem of oil flowing into the t-case deprived it of oil at high speed. I eventually junked the trans. many would agree that you may be looking at that since input shaft bearing replacement is a difficult procedure requireing extensive (and expensive) trans rebuild expertise.

If this is indeed the problem it's not too difficult to change the input bearing. I did it on my 88 Trooper tranny.

Once the tranny is down you will need to take off the front cover

You can see the input bearing in this picture


Another with the cover off


Here is one with the front case off of the tranny, you can see the bearing that needs replaced there on the top main shaft


The front part of the tranny case will unbolt from the tranny center plate shown here you have to do this to get to the bearing.


This picture shows the front half of the tranny case off, this should show everyone that was doubting that you can change the bellhousings to mate a 2.6 5 speed to a 2.8 5 speed or a 3.2 five speed just by changing the front cover other than the front cover they are identical

Cool. That's not too bad. Maybe I should throw a new bearing on the MUA I have in my basement.... never looked into it that far.

It really isn't. You just need to make sure you seal the front and rear cases back good with silicone so they dont leak.

Joe