My back tires spin great, my front right does not spin at all and my front left barely spins. If I spin my left or right front wheel, it spins freely and the other does not move at all. It seems the center drive bone turns fine, but maybe something is wrong inside front gear box? I am new to Nitro so I have no clue where to start. What should I be looking for? How do I get access to the gearbox?

check your set screws. They are probably loose. might need to put some locktite on them. I just went throught the exact same thing with a MMGT. I put locktite on today. waiting the 24 hours for it to set up.

BTW, the set screws are really little. probably on the cup on the dogbone right next to the differintial that leads to the wheel. I think a lot are 2mm or 3mm allen size.

I agree with checking the set screw first. Knowing what kind of car you have would make it a little bit easier. Depending on the setup, i.e. 3 diff setup, cvd's, etc. That will help diagnore the problem.

Stabalize your two rear wheels on the ground, lift up the front and try to spin both wheels. If your setscrew is in place and the other wheel doesn't turn, then you might need a new diff. If you happen to have cvd's check to make sure they haven't lost a set screw also.

Ha...wished I would have checked this again before I took apart the front gearbox. BTW, the truck is a MGT 3.0. The set screws on the drive cup were loose. After I put the gearbox back together all I needed to do was tighten up those screws and walla...fixed. Lesson learned, always check simplest parts first!

That's funny that you took it all apart. The only reason I say that, is b/c I had the same thing happen just a couple days ago and I bid on a diff on ebay. I then posted the a similar question here and, as you said, "walla" fixed. Well, I ended up winning the ebay diff. Did you put loctite on them after tightening them? I used the blue locktite.

one more thing about the set screws. you have to tighten them down on the correct part of the shaft they tighten on. There is a small endention on the shaft that helps hold them in place. I had to take off the dogbone to rotate the cup untill I saw the endention.

I would use red locktight on them.... One of the few places on an RC where red locktight is necessary....