4 wheel drive problem, PLEASE HELP!

[Gatecrasher]

(this is for a gen1)
ok i just got the 4 wheel drive kit and the little red gear that connects from the drive shaft to the front differential keeps sliding off. it does not fall off, but it does to the point where it does not make much contact to the drive shaft therefore just jutters but does not turn.
does anyone know how to stop this from happing? do i remove the little yellow bushing?

[RodsRUs]

I just have to say this because someone else will...do you have the right drive shaft in it lol
your prolly do considering your prolly using the one that came with it..
just make sure everything is tightened down enough and the red gear is seted properly

[Gatecrasher]

ummm no, i have not changed the drive shaft...
the little red gear keeps slipping forward is all, and everything is tight so i dont know whats wrong

[kuecker_dj09]

see if your rear bevel gear is seated on the DS the right way. it might not be inserted in to gear that spins the rear wheels the right way and ur DS may be slipping out of the front to compensate for the gear that isnt seated