[b3lha]

You know more about this than I do Trevor.

Perhaps you have a solenoid problem and your front wheels are not being driven. Have you tried inserting the diff lock fuse and seeing if it makes any difference?

As I understand it, the rear diff has a viscous coupling which requires a substantial speed difference between the two rear wheels before it binds them together. Possibly one rear wheel was spinning and the other was stationary. When you increased the RPM, the extra spin locked up the rear diff and got you moving?

Phil.