Odd tranny behavior...

So I've been experiencing some bumping from my tranny ever since I bought my XJ. It's a 96 Country 4.0 AW4, original powertrain with 140k on it. When driving around, it's fine. It's low speeds, stops and starts where the culprate surfaces. When I'm coming to a stop, just before I do, it bumps. It either does the bump then, or right when I let off the brake and go for the gas from a stop. If driving for long periods of time, the problem is more pronounced. I have done 3 rounds of the slow progressive flush of the transmission, changing the pan fluid only. The fluid is looking better, but the changes have made no difference in this issue. I'm getting concerned that the tranny may be on its way out. Anybody have any insight on this?

Did you check the transmission mount? When you describe a bump I would be looking at the mount not the actual transmission.

Jack up the rear end and put it in neutral. Check to see if you have any play on the rear gears. That might cause the bubmp too. Does it shift fine when you drive it? When you took off the pan did you see any metal in the oil?

The rear drive shaft needs to be pulled and the splines lubricated probably. That year is not lubed by the trans and the splines tend to grab. Search- was a writeup on what lube to use somewhere.

iwannadie said:

Did you check the transmission mount? When you describe a bump I would be looking at the mount not the actual transmission.

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Haven't checked that yet.

perez1989 said:

Jack up the rear end and put it in neutral. Check to see if you have any play on the rear gears. That might cause the bubmp too. Does it shift fine when you drive it? When you took off the pan did you see any metal in the oil?

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It shifts fine while driving, smooth as glass. Haven't dropped the pan but the fluid I've drained so far hasn't had anything in it. I know that's not entirely definitive, but at least mildly hopeful.

What orange said. Classic slip spline issue.

Definitely check your engine and trans mounts.

As the other have said, lube the slip spline and use the HEAVIEST grease you can get.

Forgive my newb-ness, but I'm assuming the slip yolk is the end that goes into the tranny? I'll probably have my mech. (friend) change the U-Joints while he's in there. Is this a common issue in XJ's?

See Bayhunter's post, how to...with pictures, in other thread "Clunk as I accelerate??" today.