I was running my thunder tiger mt4 g3 today and the dog bone that is a at the front of the car wasn't move but the back one was, I tried to fix it but I didn't know where the problem was I opened up the centre diff and the gears were ok but the problem still wasn't fixed. I did change the pinion gear last night could that have anything to do with it. have you guys got any suggestions on was the problem could be.cheers

I also notice that when I lift the truck off of the ground the wheels spin like its ok both front and back, but when I put it on the ground on the back dog bone moves. I also noticed when I took apart the centre diff there was not much oil in there do you think topping it up to 80% would help.</p>

cheers</p>

Do this...<div>
</div><div>Hold the center diff still and roll the REAR wheels only. Do the fronts turn in the opposite direction? Try the opposite (roll fronts with rear off the ground). Does it seem smooth?</div><div>
</div><div>Lift up the front of the car, and turn the motor pinion or spur gear by hand with the rear wheels on the ground. The fronts should rotate forward very slowly. To be honest, from what you said (though you really should try to explain better) it sounds like there is a problem with the ring and pinion at the front diff, but it could be anything really. If you have the ability to make a vid to show better what the problem is, that will help.</div>

the dog bones im talking about are the ones in the middle of the truck next to the spur gear, and the front one only moves when the wheels are of the ground. when I move the truck on the ground the spur gear doesn't  move and either dose the pinion so I can really stop the centre diff from moving because it not moving any way...</p>

don't worry I found the problem. the grub screw came loose on the long dog bon that connects to the rear diff.