Questions and Answers

Safari Drive Line Vibration Q. I have a 1993 GMC Safari All Wheel Drive Van. It has a very bad vibration/chatter when the vehicle is under load (mainly in overdrive but sometimes in drive). I checked the U-joints on the front and rear drive shafts, they are OK. However, the spline on the front end of the rear drive shaft where it connects to the transfer case has some "play" in it.

I have not checked the U-joints on the front end as I do not know exactly how the front end works on the van and they have the rubber boots on them.

I removed the front drive shaft from the van and the vibration/chatter is considerably better but, has not completely gone away. I think it is in the spline on the rear drive shaft. I can't find a repair manual that covers AWD's so I can't figure out if I can fix this or not. It appears that the tail piece of the transfer case is removable but am not sure how it accepts the male spline of the drive shaft. Can you help me with this problem?

Bill

A. Locating a drive line vibration can be a very frustrating process. The problem can be in the drive shaft, the axle shaft(s) or inside the transfer case. GM had problems with all three in that vehicle. I think in this case the best thing to do is take it to a GMC Dealer and they will be able to check it out and apply any countermeasures that apply to your van.

This is not something you'll be able to do since it will probably require running the van under load on a lift.

Additional Information provided courtesy of ALLDATA