My buddys 97 Blazer is having transmission issues. It doesn't seem to want to go into 4th gear, first to second and second to third is ok then when it tries to upshift at about 45mph it just hits the redline. He just had the tranny fluid changed at the dealer 2 months ago. The blazer has 140,000 miles on it. Should we change the fluid again put in an additive and see if it gets better? If so do I need anything besides fluid and additive(pan gasket, etc.)? I am a competent VW/Audi mechanic. If it came to it, how hard is it to swap in a new/reman tranny? I've never worked on a blazer. I do have access to a lift and basic tools. Thanks in advance for the help.

 

a faulty shift or tcc solenoid will cause such things, but I'm pretty sure a 97 would throw a code if that was the case. check the fluid to make sure its where it needs to be. too much fluid can also yield poor shifting.

 

my 97 throws cod 1080 when ever i drive more that 40 miles and starts shifting hard inbetween 1-2 gears but as soon as i clear the code with my reader and let it cool down its all gravy but 4th is always good for me