OK...Been to 3 different Ford dealers and get similer responses. Vehicle is 99 Expy. The symptoms are a low frequency shudder or moan and vibration coming from the front axle when accellerating from a stop. For example, when stopped at a stop sign and turning to the cross street. I have tried in 4 wheel while in dirt as well with same results. I am not in 4 wheel on the street although the truck does have the AWDrive. Dealers say that service bulletins indicate this is normal, 2 even showed them to me. They say that tire size needs to be the same, (they are) and that it is more common in AWD. Problem is, it just showed up at 130000 miles after a alignment. The printout from alignment shows everything in normal range, no shims were needed. Truck runs straight down the hiway. Any one else suffer this? What is the fix?

 

At this distance, it is difficult to determine how bad the vibration is. i.e., can you live with it or not. However, the problem is most likely caused by the motor/transmission/transfer case mounts getting old and not providing the dampening effect they used to. The mounts have hard rubber bushings in them, just like the control arms on your suspension; and yes, the culprit is the AWD. Unlike 4WD, there is always some activity and connection between the half shafts and your front wheels. Whether you need to replace the mounting hardware or not depends on how bad it bothers you. I doubt that it would actually cause you any problem. For peace of mind, I would also check for excess play in the constant velocity joints. Worn CVJs are a common problem in front wheel drive vehicles. Good luck.

 

All good info to keep in mind on these AWD Expys. However....this JUST started after the alignment. I was just under the truck and the lower ball joints, tie rods (both inner and outer) and all the steering bushings are still real tight or new or in great condition. If not that it just started, I would be more apt to say something is worn out. This definatly sounds like axle wind up. The question is, how to make it stop.

 

My 99 Navigator did the exact same thing, but it was after the rear end seal was changed. The dealer did not add the friction additive, and under acceleration turning it would shudder. I added a bottle and the noise/shudder was completely gone. Don't know if this helps or not since an alignment wouldn't have anything to do with the rear axle or front axle, but it sure sounds like what my truck was doing.

 

Thanks tw-I am pretty sure this has to do with the front end.

Does anyone know whether or not the cv splines that go into the front hub need to be lubed if they are taken out? For instance, if the lower ball joints were replaced and the chafts were removed for access.

 

They do not need any lube. Try driving with the front driveshaft removed. It will set GEM codes but those codes won't affect the symptoms. If they go away the problem is in the t-case. If they are still there look for problems in the front end.

Regards

Jean Marc Chartier

 

Thanks JMC...sounds like a good thing to do on my next weekend. Will report back.