93 S10 Blazer 4.3 Vortec………. I'm having intermittent transmission/4wd/? problems. The truck will shift up with speed but when required will not drop down a gear, you have to use the selector manually. When this happens you loose 4WD controls. Then for no reason as you are driving the 4WD lights will come (some times only) on just like when you start the car and the transmission will work properly. Could this be a computer problem? or is there something else that these two systems share? HELP !!!

my suggestion is to go to a local tranny shop and have them hook onto the computer in ur blazer. Hopefully it will read out okay but if not at least youll know the code to whats wrong.

trannys on blazers are SHIT and mine blew 2x the month i got mine. I had it rebuilt twice. My guess is that you might have a blown syninoid or some type of component in your blazer which isnt allowing the downshifting to happen..

i might be wrong though because my truck wouldnt manually shift OR go into 2nd, overdrive or reverse. Good Luck.

my suggestion is to go to a local tranny shop and have them hook onto the computer in ur blazer. Hopefully it will read out okay but if not at least youll know the code to whats wrong.

trannys on blazers are SHIT and mine blew 2x the month i got mine. I had it rebuilt twice. My guess is that you might have a blown syninoid or some type of component in your blazer which isnt allowing the downshifting to happen..

i might be wrong though because my truck wouldnt manually shift OR go into 2nd, overdrive or reverse. Good Luck.


also, the tranny shop shouldnt charge you anything to have your computer checked.

I have to agree, the trannys in these are way to weak for the abuse that they can see. However, it sounds like you are experiencing a vacuum problem. You might have all of the vacuum lines and modulators checked out and see if something is going bad there.