Driveline vibration

I recently bought a 94 Wrangler with 6 cyl, auto trans, and a 3" lift with 32" tires. It runs strong and had no apparent problems. I did a complete service of the vehicle including changing the oil, transmission fluid, and front and rear differential fluids. Because of the lift the transfer case drain plug is blocked and I haven't had time to drain the T-case so I just topped it off.

Everything seemed fine for a couple of weeks but now I am experiencing strong driveline vibration just before the transmission shifts from 2nd to 3rd. I am also having trouble shifting the transfer case case to 4wd Hi and it is very difficult to get 4wd Lo at all.

I am also trying to make sure whether the rear diff is open or limited slip. I tried the old trick of jacking it up and spinning one tire. The opposite tire doesn't move so I am not sure what to make of that.

Any ideas would help.

-cv

I recently bought a 94 Wrangler with 6 cyl, auto trans, and a 3" lift with 32" tires. It runs strong and had no apparent problems. I did a complete service of the vehicle including changing the oil, transmission fluid, and front and rear differential fluids. Because of the lift the transfer case drain plug is blocked and I haven't had time to drain the T-case so I just topped it off.

Everything seemed fine for a couple of weeks but now I am experiencing strong driveline vibration just before the transmission shifts from 2nd to 3rd. I am also having trouble shifting the transfer case case to 4wd Hi and it is very difficult to get 4wd Lo at all.

I am also trying to make sure whether the rear diff is open or limited slip. I tried the old trick of jacking it up and spinning one tire. The opposite tire doesn't move so I am not sure what to make of that.

Any ideas would help.

-cv

I have a 97 Wrangler and it has the Danna 44 rear end. I to jacked the car up and spun the rear tires both go in the same direction. I talked to a dealer about this and they said that that model was offer with a trail lock package "Locker" of sort.

You said that one tire spins and the other does not? did you do this test with both rear tires off the ground? Also, there may be a tag on the rear diff if it is still original that will have all the info you need including gear ratio. If one tire spins and the other does not , this sounds like it could be a standard diff and not a limited slip.

Another suggestion take the VIN to the dealer and they can pull all the specs on that vehicle as it was originally sold. hope this helps.

Does it seem like the trans is thinking about shifting and shuddering a bit? Try giving a little more gas or letting off as the shuddering starts. Might be that the trans needs a rebuild (or at least a shift kit) to freshen it up. How many miles?

Did you check your u-joints?

That was my problem when I was experiencing strong vibrations.
Just an idea.

Plus, if it is a u-joint, it is a cheap fix and easy to do yourself!

Hope it helps.

did you look into a slip yoke eliminator and a longer driveline to your rear axel? when you get a lift over 2 inches it def helps.

when you lift a jeep the drive line angle is too great. if you get a slip yoke eliminator it requires a longer driveline indicating a change in driveline angle that is not as steep thus mechanically more acceptable in driveline physics. if you have done the slip yoke elimination then look at the u joints. if replacing them get ones that can be lubricated with a grease fitting rather than having to be repacked.

I have 32" tires on my jeep and encountered the same problem. The problem with mine was the tires. Larger tires seem to produce a problem called cupping. That is, when each tire doesn't wear flat or round. Take a look at the thread. If it looks like part of the thread is not wearing but the other half is, you are a victem of cupping. Just rotate the tires so that the tires are going in a reverse direction....