1994 k1500 suburban 4l60e issues

[Jeffery Myers]

My 94 suburban 4l60e will function normally in either drive or overdrive but will not shift into manual 1st or manual 2nd gear. When I pull it into manual 1st gear it acts like it wants to move but like ita slipping until the rpms get up and then it clunks into gear and grabs until you let it off the throttle

 

[1997]

might be setting a code, have you checked?
OBD1 sets some codes without turning on the check engine light.
google how to check OBD1 codes or get a code reader of your choice.

 

[thinger2]

Could be a bad transfer case switch or bad wiring going to the switch.
There is a gm technical service bulletin on this problem.
It is known to cause intermittant no downshifts and does not always set a trans code.
It can also happen in 2wd or 4wd
Ill see if I can find it but its been a long time since I looked at that one