Hello there, I have a 1999 Chevy Blazer 4wd 4.3L SFI 6cyl Automatic transmission and I am have a real problem with it going into gear after making a complete stop. I have taken it to 2 different machanics in which they told me 2 different problems.
Problem #1 torque converter
Problem #2 transmission valve body

I wasn't too sure on those two answers so I took the truck for a drive and then the engine lite came on. Took it to an auto parts store and the codes came back saying

: 1-2 shift solenoid valve proformance explanation
Transmission in drive-ECM compared engine speed to vehicle speed inputs and detected an incorrect shift pattern
Probable cause
Shift solenoid failure- repair other codes first
Internal transmission failures.

So they tell me to check the speed sensor and if replacing that doesn't work replace the shift solenoid. I know that the speedo. sticks so I took the speed sensor out of the transfer case and now the speedo. does not work at all. Too add to my confusion I find out there are three types of speed sensors.

I was wondering could the one I took out be the problem and the reason for the speedo. not working and the shifting problem? I dont know very much about any of this was hoping for some help from someone not trying to drain my bank account that barly has anything in it.

 

What was the specific code? Probably P0751 - Shift Solenoid A Performance or Stuck Off. Check that out and see what you come up with in the diagnosis.