Ok here's my problem. My SES light comes on and goes off, when I have it checked they say the code is p1870. But the light is out and the tranny is running up to specs. When I run it for a few days the light comes back on and it seems to jump from 1st into 2nd.
Sorry if this was posted before, I looked but couldn't find it.
Thanks for any help.

probably a transmission solenoid. Make sure you replace whatever the code is telling you. If you don't the problem will keep coming back.

I called a tranny place today and they're going to look at it tomorrow. They think maybe it's slippedge in the torque convertor. Really glad i got an extended warranty.
Thanks for your help.

No problem.

my 97 blazer valve body in tranny takes a couple of hrs to heat it up then it sets code 1870 hard shift 1 to 2 gm wanted 500.00 parts 4-500 labor aamco rebuilt it for 400.00 my gas mileage went up abt 3-4 mpg with repair it is a known problem on the 97

took it in today. it's definitely the torque convertor. warranty co authorized a repair with a rebuilt tranny...at this point I just want it fixed without having to pay anything.

took it in today. it's definitely the torque convertor. warranty co authorized a repair with a rebuilt tranny...at this point I just want it fixed without having to pay anything.

still sounds like the valve body and not the torque converter.

these trannies suffer from valve body problems, and it causes the tranny to command maximum line pressure, which is what causes the harsh 1st -2nd shift.

they also said something to the effect that other parts of the tranny needed repaired, and they are doing that too. I guess I'll have to wait til I get it back to see if it's ok.

This really turned out to be a nightmare. The warranty co wanted to out in a used tranny, they ok'd $1200 and that was it. Not having a choice I said ok do it, well they tranny place "Cottman Transmission" misunderstood and put in a refurbished one...the finally cost minus the warranty $1024. Luckily I have a good hubby, I went crazy and yelled and screamed at the guy, told him I didn't have that kind of money and that they screwed up, but hubby thought it was best to have the one they put in, because he was worried the used one would end up like the original one.