P1870 code, now what?

[kanz]

Ok guys I had the 1870 code on my 97 Tahoe and had my tranny shop rebore the valve body. I put 6,000 miles on the truck since and it ran flawless. So I Start the truck up this morning and immediately get the check engine light. as I pull away I immediately get the hard 1-2 shift. Now what? I just drove the truck before and it was driving fine. Any suggestions? Thanks

 

[Sepiroth]

Thats a trans component slipping code. 9/10 of the time, the torque convertor is the culprit. As from my experience, a trans overhaul is in order.

 

[shawnkfl]

could be the valve body solenoids. i would start there before taking any drastic rebuild steps. replace the solenoids. if that didn't fix it, take them back for a refund and dig deeper

 

[kanz]

Thanks guys. I drove the truck today on the parkway and stop and go traffic and could not get it to have the hard 1-2 shift. If it was the converter it would be constant correct? thanks