i have a 94 s10 Blazer 4X4
i have a question, and a problem that has me stumped.

First the question: Is there any way to convert to a manual shifter for the 4x4? like if i went to a junkyard and got the shifter and stuff?

and now the problem.
The transmission is shifting way early, intermittently.
like so:
Starts out in what seems to be 2nd
Shifts to 3rd at like 10-15
shifts to 4th at like 20-25
engages the TC at like 25-30
When it does this the 4lo light comes on.
Sometimes i can hit the 4lo and it will stop, others it just ignores me pushing the button.
It seems like it mostly starts/stops when i hit bumps (im from michigan so there is alot of them)

Ive replaced the tccm, encoder motor, and the vacuum switch on the t-case. (still didnt fix the 4x4)

After i replaced the encoder motor, it stopped doing it for about two weeks, then i went down a really bumpy dirt road, and boom, started doing it again.

Could the switch on the front axle be affecting this?
Im completely stumped as to what could be causing this. to my understanding the 4x4 has no affect on the transmission shift patterns, so any input is greatly appreciated.

 

ok, so i unplugged my tccm, and voila, it ran fine, im still majorly confused however, input please?