[JThiessen]

Desert - I can only assume that you are also using the factory manual to make sure you have all the correct parts. First you need to check that you have the shim in the right spot (shims one of the diff supports up due to a relief milled in the chassis).
Next, double and triple check to see if the diff assy is reversed or not. Then make sure your orientation of all parts are also reversed......I dont believe the Losi kit reversed the diff assy, but cant remember for certain.

It's probably something easy/minor that you may have overlooked.