I have a '92 Dakota 4wd with limited slip (Posi) rear, which after running for over a half an hour at highway speeds starts to bind up and pop the rear axles while turning even slightly. This is a loud binding and popping from the axles as the clutches release, is there any way to stop this from happening, I'm worried that it will damage something. It doesn't seem to affect performance because I'm getting pretty good mileage for a 5.2 around 18-20 mpg highway.
I've checked the fluid level in the rear and it is fine, also added friction modifier thinking it might help. Is it possible to have too much friction modifier in the rear, possibly causing the binding? Does the modifier help the clutches to grab? I am thinking about draining the rear lube and replacing it with regular lube without the friction modifier. Or does the rear clutch pack need adjustment or shimming? If so, how is it done? Any advice appreciated. Thanks. Tom.