Multiple Problems

First problem:
When I am driving down the highway and take my foot off of the gas pedal and coast, I hear a sound from the rear differential. It sounds like some trucks when they coast.
Second problem:
It's related to the above, when I take my foot off of the gas pedal, it feels like it downshifts, this happens at speeds between 40 to 60 mph, anything above or below those speeds, doesn't have that effect, except I can hear that 'whirring' sounds.
Third Problem:
When I let off of the gas and the two problems above take place, I feel some 'slack' from the drive train. When I say 'slack', it means I feel something moving down there.
Fourth Problem:
When I make a sharp turn into a parking space, my front wheels make a sound like I am 'peeling out'. I also hear a 'clicking' sound coming from my driver's side front tire, I think it may be the loose cap on the rim. The rim looks like this: That cap is loose, but I am not sure it's the source of the 'clicking' sound.


Fifth and Final Problem:
When I am in reverse and it goes above a certain speed, I hear a funny sound and feel a small vibration, almost like the driveline is buckling(minor) or something.

Other than that, the Jeep drives great! I have good oil pressure, the temp is nice and cool, 195 to 200F most of the time. The jeep shifts well and runs strong. the wife and I are going to take a trip (with the Jeep) to see her sick Dad in Georgia, and visit her mom in Florida for the holidays and i want to make sure that we won't break down. Any help or suggestions would be greatly appreciated!

Here are the specs of the Jeep:
1996, AW4 Trans, 2wd, 130k miles. Build date 4/96

Sorry to dump a whole bunch of problems at once. I just want to make sure we can make it there and back with no problems.

This will give you some ideas on differential issues:

http://www.ringpinion.com/FAQ.aspx#14

For 3 and 4 at first I thought you might have a lunchbox locker up front, then I saw its 2wd. You likely have an alignment issue. Put some duct tape on that cap and drive it, see if it makes a difference.

For 5 check your driveshaft u-joints, could also be related to your issues 1 and 2.

joe_peters said:

This will give you some ideas on differential issues:

http://www.ringpinion.com/FAQ.aspx#14

For 3 and 4 at first I thought you might have a lunchbox locker up front, then I saw its 2wd. You likely have an alignment issue. Put some duct tape on that cap and drive it, see if it makes a difference.

For 5 check your driveshaft u-joints, could also be related to your issues 1 and 2.

Click to expand...

Thank you for your response sir!!! My tires were recently aligned. I will try the duct tape tomorrow (great idea!).

I was hoping that it was the u-joints instead of a major problem.

I changed my diff fluid recently as well. What I have done is feel the 'pumpkin' right after driving and it was not hot, it was actually only moderately warm.

Updates to follow! Thanks again.

When you changed the rear diff fluid, did you put the limited slip additive in? If not, that's why you have problem #5. Happened to me.

sw4218 said:

When you changed the rear diff fluid, did you put the limited slip additive in? If not, that's why you have problem #5. Happened to me.

Click to expand...

No, I didn't put the LSD additive in. I thought that I had an 'open diff' with my 2wd 8.25. I guess the best way for me to know if I have the LSD or not is to jack it up and spin the wheels?

joe_peters said:

This will give you some ideas on differential issues:

http://www.ringpinion.com/FAQ.aspx#14

For 3 and 4 at first I thought you might have a lunchbox locker up front, then I saw its 2wd. You likely have an alignment issue. Put some duct tape on that cap and drive it, see if it makes a difference.

For 5 check your driveshaft u-joints, could also be related to your issues 1 and 2.

Click to expand...

The duct tape fell off because there was 'brake dust' on the rim. I will try again tomorrow when the weather is better and report back. Thanks again for your suggestions.

For the front wheels, if the duct tape won't stick you could remove the wheel and put it back on without the cap. If you still get the clicking, then the only thing I can think if with a 2wd model is front wheel bearings, ball joints, or TREs. The basic test for those is to jack up that end and grab the tire firmly at 12 and 6 o'clock, and try to wiggle it. There shouldn't be any play. Repeat the test for 9 and 3 o'clock. If there is much play in either plane the ball joints and/or wheel bearings could be bad. A shot TRE could make it do some funny things as well, the best way to check those is to pop them loose and work the ball stud by hand; replace any that are loose. It would be a good idea to check all of the steering linkages- one way is to have a helper turn the wheel slowly back and forth while you observe each part move. Not sure if any of that would cause a clicking noise or squeeling tires, but it's nice to rule stuff out.

Are you sure the 'peeling out' noise is coming from the front tires? I know my rear tires will do that in 2wd around a sharp turn at low speed.

The slack/slop in the driveline is most likely due to bad u-joints and/or motor/transmission mounts.

If you change your u-joints, grab the pinion yoke and try to move it up/down, side to side. If there is much play there the pinion bearing could be bad.

Also, you said it feels like it downshifts when you let on the gas. Do you mean that you feel something dragging, or some extra resistance that slows you down? Or do your revs actually rise?

Robs92XJ said:

For the front wheels, if the duct tape won't stick you could remove the wheel and put it back on without the cap. If you still get the clicking, then the only thing I can think if with a 2wd model is front wheel bearings, ball joints, or TREs. The basic test for those is to jack up that end and grab the tire firmly at 12 and 6 o'clock, and try to wiggle it. There shouldn't be any play. Repeat the test for 9 and 3 o'clock. If there is much play in either plane the ball joints and/or wheel bearings could be bad. A shot TRE could make it do some funny things as well, the best way to check those is to pop them loose and work the ball stud by hand; replace any that are loose. It would be a good idea to check all of the steering linkages- one way is to have a helper turn the wheel slowly back and forth while you observe each part move. Not sure if any of that would cause a clicking noise or squeeling tires, but it's nice to rule stuff out.

Are you sure the 'peeling out' noise is coming from the front tires? I know my rear tires will do that in 2wd around a sharp turn at low speed.

The slack/slop in the driveline is most likely due to bad u-joints and/or motor/transmission mounts.

If you change your u-joints, grab the pinion yoke and try to move it up/down, side to side. If there is much play there the pinion bearing could be bad.

Also, you said it feels like it downshifts when you let on the gas. Do you mean that you feel something dragging, or some extra resistance that slows you down? Or do your revs actually rise?

Click to expand...

I didn't have time to pull the front wheel off today, but I will do that tomorrow.

Yes, I am pretty sure it's coming from the front tires. Ironically for the past few cold days we have had here, I don't hear the sound.

If I had to choose, I would choose feeling a little extra resistance, but there's not a drastic drop in speed. The rpms don't go up. This mainly happens when I take my foot off of the gas quickly. If I ease my foot off of the gas gradually, it behaves a lot better. This mainly happens around 50 to 60mph, if I am going 65mph or a little above, there's no 'downshift feeling' or that 'whirring sound'. When I go 35mph or below there no sound and no 'downshift feeling'.

I appreciate your advice and everyone else who gave me advice on this thread. I will keep following up as I go along. This way if someone has a similar problem, the 'knowledge base' will be available. My friends are all pretty busy this week. I think these are the things I am going to check/replace intially:
1: Check Tranny mounts
2: Replace U-joints

Hopefully it will be an improvement and I am pretty sure they haven't been replaced by the previous owner.

Well, I got in touch with my friend who is a Jeep tech. I will have the answers on Sunday. I will post them here afterward.

As promised, here's an update:
U-joints checked out ok.
The ticking was coming from that cover.
The diff fluid was changed.
With the diff cover off, we inspected the gears (I should say "he" ) there were no metal shavings and he was surprised. The "lash" was a little bit off. What we did see was that the center pin had some wear and the spider gears/differential dears were loose, we are going to replace them with these:
http://www.quadratec.com/products/52412_15.htm
Then we will see what happens. If that doesn't make the sound go away, we will replace the ring and pinion gears.