1994 Chevy S-10 Blazer Lt
4.3l CPI Vortec w/ 4L60-E 4x4 push button tranny

Not really a tranny guy but consider myself somewhat mechanically inclined. My blazer always had a firm shift from 1-2 but never to bad. Pulled out on the road the other day and when it shifted violently from 1-2 it seemed like the front tires were pulsating locking up and then shifted. I immediately turned to my 4x4 cause from driver tire is always engaged but shifts smooth manually. Now I expect a mechanical failure in the tranny, transfer case, or diff. will not go away regardless of auto or manual shift. Now im turning the attention to electrical for which ive read a bad PCM or solenoid could cause this.

Everything works fine on the truck, it shifts into 4hi and 4lo with no problem, pulled engine code with no codes coming up but not for sure if the PCM will pull codes for tranny(out of my knowledge base). Still yet no matter 4hi, 4lo, or 2 whell still has the shift problem from 1-2 and a clank going to 3(periodically). Any help much appreciated.

 

Still need some help!!!

 

Anything in the post below sound familiar?
4L60E Information & Common Problems - Compilation

 

I appreciate the link you gave me and it was very informative. The only question that really still stands for me is I have an ECM and a TCCM. There is no combo in my truck to give me a PCM so which one would I swap out for the good one??

 

The engine computer also runs the transmission. The TCCM is only for the transfer case.

 

Ill be damn...I knew the TCCM ran the transfer case for the 4x4 but I always thought it also ran the whole transmission in general. As I said before not really a transmission guy so bare with me on this...Could the ECM fail only on the transmission and have everything else working properly?