I have a 97 blazer 4wd 4.3. I just had the transmission rebuilt and have around 1000 miles on it. I can crank it up, put it in reverse, it engages and backs out of driveway, put it in drive and it will pull up to the road, but then acts like it's in neutral. With hard acceleration it will either grab quickly and bark tires or engage slowly and feels like its a straight drive and like you are letting out the clutch. As long as you accelerate hard it stays engaged but the second you let off it's back in neutral. Fluid is full, maybe a little over. Cant stand the thought that I got 1000 miles for 1000 bucks. Tell me its not a new transmission im looking for!

 

Did you try shift manually

 

It will engage the first time I put it in gear. I have only moved it a couple hundred feet. It will pull out of parking space to the road but once I stop its like its in neutral. Any gear I try to start out in is the same. Can really rev it up and it will either kick in hard or feel like you are letting the clutch out on a manual.

 

I would see if you find a code reader that can tanny codes. Could be a lot of things. Torque converter, selonoid

 

p1870

 

I had the P1870, but not the symptoms you're experiencing. My OD wouldn't work after the tranny fluid warmed up.

What I did to fix the P1870 was drop the trans oil pan, remove the valve body, and replace the TCC valve with a Teckpak TCC valve which is just a metal plug without the spring. This code is usually a problem with a worn valve body. Solved the issue, but I'm not sure what could be causing your issue

 

Drove it around yesterday enough to get the code. Starting out is like revving and letting out the clutch on a manual. Up through the gears pretty normal, downshifts fine when I put it in other gears, but sometimes at crusing speed slips out and revs til it catches again, and any stop its like a manual again to start off. Reverse the same like a straight drive.

 

Dont keep driving it, it may hurt something else. drop the pan and change the tcc valve, or bring it to a shop. if its just valve it wont cost much.

 

Transfer case seal bad. 2 qts high in fluid in transfer case and 2 qts low in tranny

 

you could pull the transfer case a fix the seal or you pull the top fill plug and drain it down to the proper level. Then monitor it after that