Problem: The threaded lock nut on thrust shaft in the rear gear assy. keeps backing off and binding with the middle drive shaft going to transmission. Ist time snapped the shaft, twisted gear assy..off the frame. Replaced shaft etc. next time spun the nut, ate the threads, twisted gear assy off frame,tore up inner cv joint. Getting expensive. My thinking manual transmission, itp mud-lite tires 27-12-12 rear maybe too much torque plus letting son use it. Any suggestions or help would be great.

 

I have not had that problem with mine I do have a problem with wheel bearing I have 26s 589 on mine

 

Thank You for input. I also had changed one of the rear bearings. Just ordered the new parts again.I'm going to try stock tires to see what happens. Just for info : I had to go to 2003 4004x4 to get the rear assembly parts breakdown, the 2002 400 just has the whole assy. for sale at $800.(same #). Discovered this on my own. Parts $150.