Code 1870 with a solution

Anything related to the stock drivetrain, engine, transmission, axles, wheels...

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BDiefAZ
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Joined: Thu Dec 27, 2007 5:25 am
Location: Cave Creek, AZ

Code 1870 with a solution

Post by BDiefAZ »

I noticed that my truck was starting to have revs between 2000 and 1800 while traveling up a slight incline while holding spped between 55 and 60mph, assuming it was the truck locking and unlocking the overdrive, no action was taken.

Last week, it progressed to slam shifting from 1 to 2 after running on the freeway for a while, then it would not shift into overdrive and the SES light came on. I plugged in my Hypertech and read the codes and it was the 1870 code. I immediately cleared the code, and returned the "shift firmness" back to stock and the truck was running fine again. The truck then lived in the garage until parts arrived...

I ordered a rebuilt valve body from a seller on ebay ($90 shipped), a trans-go separator plate ($20), solenoid screens, piston seals, transmission fluid and new filter/gasket kit (total of about $150). The job took about 3.5 hours and was completely worth it. The truck now shifts smoothly, holds gears longer, and has much better response.

When removing the valve body and transmission shift plate, it was clear that the shift plate was beginning to wear. One check ball had almost worked through the hole in the plate and the others had begun to peen the holes. The piston seals may have been worn, but nothing was visible. You will need a torque wrench capable of 48, 65, and 96 inch-pounds to do the repair.


Source for the valve body:

http://stores.ebay.com/GLBTRANSMISSIONS

Greg is an excellent vendor and will even offer tech support by phone if you have installation questions or general transmission inquiries. Between his enclosed instructions and the videos available on the internet to install and replace the valve body, it was very straight forward.

The Trans-Go separator plate:

http://www.transgo.com/separatorplate.php

Hope this helps, if any of you are having any of these transmission issues.