I have a 1997 GMC Jimmy 4x4 And its goes into gear fine and all the 4x4 ranges work but in any 4x4 or 2H if I really step on it, it will go to about 2200 rpm start stuttering and stick and I have to put my food to the floor to get the revs continuing to go up. If that happens it won't shift until about 4500rpm into second and will then do the same in second. But if I do a smooth acceleration it won't happen as often. I got the trans flushed if it matters. And there is a fairly loud rattling noise on the passenger side underneath.

 

Have to put a OB2 diagonistic maching on the car yet. If you get P1870 codecome up its the shift valves in the gearbox.