Questions and Answers

Dakota Vibration Q. My 1999 Dodge Dakota Sport, V-6, was vibrating and knocking in the rear only at very low speeds and only when turning or in reverse. The dealership replaced the rear end fluid with some sealer and fluid, saying the clutches in the rear end were not functioning properly due to the breakdown of the viscosity in the original fluid.

Clutches in the rear end???

It has been years since I worked on vehicles other than minor maintenance but I had never heard of this. Anyway the fluid change has had little effect on this problem. I only have 50,000 miles on this truck, is this normal and what are my options? Will this become more of an issue or should I ignore it?? Most of my driving is at highway speeds about 100 miles a day.

Thanks,
Donald

A. You must have the Trac-lok differential in there. There are clutch packs in it to provide positive traction.

In a conventional differential, if one wheel spins, the opposite wheel will generate only as much torque as the spinning wheel. In the Trac-lok differential, part of the ring gear torque is transmitted through clutch packs which contain multiple discs. The clutches will have radial grooves on the plates, and concentric grooves on the discs or bonded fiber material that is smooth in appearance.

In operation, the Trac-lok clutches are engaged by two concurrent forces. The first being the preload force exerted through Belleville spring washers within the clutch packs. The second is the separating forces generated by the side gears as torque is applied through the ring gear.

The Trac-lok design provides the differential action needed for turning corners and for driving straight ahead during periods of unequal traction. When one wheel looses traction, the clutch packs transfer additional torque to the wheel having the most traction. Trac-lok differentials resist wheel spin on bumpy roads and provide more pulling power when one wheel loses traction. Pulling power is provided continuously until both wheels loose traction. If both wheels slip due to unequal traction, Trac-lok operation is normal. In extreme cases of differences of traction, the wheel with the least traction may spin.

There was a TSB issued about a new type gear lube and I think that's what they did in hopes the new lube would fix the problem. This vibration is not normal and since it manifests itself in reverse and turns, I'm fairly certain it is in the rear. I would push Chrysler on this one and keep pushing until they either fix this differential or replace it.

Additional Information provided courtesy of ALLDATA