Transfer case output shaft play

[DidiDavis]

Hi all,

I've had a 1996 Explorer Eddie Bauer V6 4wd for about 2 years. I've been having a vibration at highway speed since I bought it. It starts at around 60 mph and it gets worst as I go faster. When I release the gas pedal and the weight shifts to the front of the car, the vibration gets worst. The vibration is dependent on vehicle speed, not engine rpm. The vibration seems to be coming from the rear of the vehicle.

I replaced the shocks and axle damper, which were shot. It helped a little bit, but the vibration is still there. Got new tires, wheel balancing and alignment, it still vibrates. My next move will be replacing both U-joints of the rear driveshaft. They look ok, but at 9 bucks a piece it's worth the try. I got under the truck to check them out and noticed that I have a small play at the rear output shaft of the transfer case. The shaft moves a bit up (only up, not down), I'd say less than 1/8", and makes a clicking noise. The play is not on the U-joint, it seems to be either on the flange or output shaft, more likely the output shaft. Is that normal? Have you guys ever noticed if you have that play? I'll tighten up the nut holding the output flange onto the shaft, but it really looks like the play is on the shaft itself.

I've also checked the center axle disconnect in the front axle and it is working fine. Ball joints, steering rod, sway bar links and all other components are ok, therefore I'm ruling out the front axle and front driveshaft as the source of the vibration.

Any ideas?

Thanks

 

[drdoom]

It could be the rear bearing in the output shaft going bad. You'll be able to tell when you drop the rear drive-shaft.

 

[DidiDavis]

Thanks for the reply. I'll tackle it during the weekend. I probably should start searching for the "wheel replacement how to". Do I have to drop the transfer case or can it be done on the car?

Thanks

Edit: Alright, found the rebuilt thread, and I do have to drop and split the TC to replace the bearing. I think I'll try replacing the U-joints and having the drive shaft balanced before messing up with the TC. Maybe a U-joint is bad and causing the vibration, which in turn did some damage to the TC output shaft bearing. The play is very small, and no oil is leaking from the seal. Maybe I can get away with a pair of new U-joints. I'll keep you posted.

 

[DidiDavis]

Update:

I've replaced both U-joints of the rear drive shaft and tried to tighten up the TC output shaft nut. The nut did not move. Once the drive shaft was removed, I wasn't able to move the output shaft by hand. The job went well, took me around 3 hours from start to finish.

Results: the vibration got better. Now it starts at 75-80 mph instead of 60 mph. But I guess that a 15 year old car will likely vibrate at 80 mph. I'm happy with the results and will not mess up with the TC. Thanks for your help!