Hello all, I was curious what would cause an AW4 to jerk when going into drive or reverse. I replaced all three mounts thinking that would fix it but it didn't. The tranny shifts flawlessly outside of that issue. I also was wondering if I was feeling the "jerk", "bang" symptom in the rear diff. Is that a possibility? This is really eating me up, shes old and crusty but soo much fun in four wheel out at the beach, I just want to protect her before it does real damage. 216,000 approx miles, AW4 has been rebuilt, theres a rebuilt metal tag hanging off of it. Thanks for your help in advance!!

 

Does it also do a similar jerk/bang when taking off from a stop or coming to a stop? I had your symptoms, plus what i just listed.

Greased the slip yoke on the driveshaft, and replaced driveshaft U-Joint = problem solved

 

No, smooth as silk taking off from start and no banging or looseness felt on a stop. I figured mounts would fix it. Thanks for your reply though!

 

Im having the same problem with mine and have had it before on my last truck. We ended up replacing the U-joints and it solved the problem on the truck so im about to do the same for the jeep

 

Yea, I'd check U-Joints. You can chuck the wheels, (or E-brake I suppose), and go under there with it in neutral, then rotate the driveshaft back and forth and see how much play you have in the differential. I can't say what would be considered normal, but it isn't much. Watch for play everywhere. Sounds like you have some somewhere!

Likewise you can jack up one rear an inch, and rotate the tire back and forth with it in park and look for play. (chuck the front wheels!)

 

Thank you all. Will jack her up asap. I have to agree, u joints sound like the culprit.