How do I replace Viscous Coupler

Ive brought my car in several times to get tuned. Each time it has gone in, the 4wd dyno pack has issues and will not function so the tuner has to tune in FWD. Today I picked up the car and he mentioned that he believes that the Viscous Coupler is bad and needs to be replaced. With that said, a few questions

1) Anyway I can test and confirm that this is in fact the problem
2) If it is the problem, how do I replace it? Is it a difficult job? Any write ups on it.
3) Any other thoughts on what it could be if not that ?

Thank you in advance for you rhelp

1) I would imagine a dyno could show how much torque is being distributed between the front and rear wheels. Should be a 50/50 split. Anything less and the VC is probably worn.

2) Its the fluid that goes bad and needs to be replaced. Unfortunately our VC's are sealed from the factory.

I believe there was a company in Europe that was offering to drain the fluid, replace it and tap a drain plug so it could continue to be changed without hassle.

Your best bet may be to talk to some transmission shops and see if they're willing to try. Otherwise you can simply weld it, not that great for a daily ride though, your wheels will chirp on sharp turns.

3) Only other advice I can offer is trying a different dyno/tuner.

Do you know how much mileage the tranny has?

It would probably be much easier to just find one with less mileage.