The front differential is actually part of the transmission housing. The most common problem deals with the spider gears coming apart resulting in either a loud noise when moving or the vehicle doesn't move at all. If the vehicle doesn't move, place it in gear and rev the engine. Does the speedometer move? If it does, the trans is working but the problem is in the differential.
To repair it, the transmission needs removed. There is enough room to remove the differential cover, but not enough to get parts out and then back in. Another concern is if you are leaking ATF. Many times when they come apart, they will actually crack or break the trans housing.
Let me know if you have other questions.
November, 25, 2010 AT 7:22 AM
I forgot to mention price. It is really based on what damage is done. If the trans housing is cracked or broken, the entire housing needs replaced. At that point, it is better just to replace the transmission because of cost issues and the miles that are alredy on the present transmission. I would estimate up to 3000. Max if the housing needs replaced. However, based on where you live that could be less or more.