i recently bought back my old 96 blazer it has only been gone 4 months since i last had it. about a month after i sold it they did a tranny flush at 160,000 becuase it wouldnt shift in to any gear. my theory for that was becuase parking on a hill and not setting the ebrake. well right after they did the flush it wouldnt take off properly flooring it bringing it to over 3000 rpms and going nowhere. it does not shift into 4th at all. when i got back it was 3 quarts low on transmission fluid thinking they didnt fill it up all the way. and unknown if they changed the filter after doing this, they paid 100 bucks for it to be flushed. seems a little cheap for a flush. i plan on parting it out if transmission is shot. ive looked at this forum and other forums for diagnosing but no specifics for this problem im having.

 

i have not scanned for codes. my theory is the torque converter shot, and 3-4 solenoid not working. it shifts manually through 1.2.3

 

Could be a solenoid issue. Could be a vss issue too. My truck has been like that for years. I have to manually shift 1-2 and 3rd gears due to the vss being disconnected. But if you're speedometer works that's probably not the case

 

Hello
A few question
How firm is second gear.
How does 3rd feel.
You could have a stuck 3-4 valve in the valve body
I just pulled a V/B in a 700R4 with 200 miles stuck valve.
I've also seem the seals on the 4th apply piston go bad.

 

I had the same problem it was one of the plugs going into the tranny came out somehow