Manual Transmission warning signs
 

'89 XJ with 180,000 miles on it.

Sign #1. About five years ago, started popping out of reverse. Getting harder and harder to hold in gear while backing up. This alone was not reason enough to take my daily vehicle off the road.

Sign #2. The other day, an ugly whining when in 2nd or 3rd gear. This was reason enough.

I'm just wondering what the forum wisdom figures these things to mean. A complete tranny rebuild is probably in my near future but I'd appreciate some experienced input meanwhile.

Two transmissions were offered that year, I need to go research which one is mine and make note of it.

The one that you should look for is the AX15. It is a much stronger trans than the Peugeot BA10/5 that you probably have. The Peugeot is prone to the case stretching causing the gears to stop meshing correctly.

here is a quick read from Novak on the BA10/5. https://www.novak-adapt.com/knowledg...manual/ba10-5/

This information suggests that I should

a) acquire a new/rebuilt AX15
b) machine the existing transfer case to fit

This seems much more expensive. Advisable, but I'm not yet in a position to put more than keep-it-running money into my Jeep.

More research is in order. Thank you!

The transfer case the you have should fit on the transmission. You are going to have to find an AX15 from around the same year as your jeep now because the input splines have changed over the years. It might be easier to find one out of a wrecked jeep and grab the trans and the case at the same time.