2004 chevy tahoe reverse but won't go forward.?

[Firas Hussein]

My 2004 Tahoe Z71 will start fine and smooth, the problem is when i try to shift. It will reverse fine with no problem but when i put it in drive the engine will rev but it won't move as if it was on idle. If anyone had that problem or knows the reason?

[guitarman1989]

Try adding transmission fluid. This is usually the cause.