XX4 diff check

[Fiddybux]

I'm running a XX4 with a one-way clicker in the front and I just cleaned up my rear diff as it felt like I had gravel in there instead of bearings . It all went well as far as I can tell (I'm not a seasoned diff rebuilder, but I followed the instruction manual closely) and now after the car has been rebuilt and I roll the back wheels forward...the right wheel turns more than the left one does.

This is not an issue when the car is under no-load, but when on a surface the left wheel seems resistant to turn, whereas the right one turns freely and spins on whatever surface I'm on (i.e. laminate, carpet, couch etc).

What's going on? Is it something to do with the tightness of the front or back diff?

I'm sure that it's not the tyres gripping as I've swapped them over and the same issue occurs.

Thanks.