Blazer Forum - Chevy Blazer Forums - How to install the Teckpak TCC valve without removing valve body and fix P1870

Hi everyone! I know error code P1870 for those of us with the 96-99 4L60E transmissions has been pretty well hashed out throughout the forum but one thing we were lacking (or at least that I couldn't find) was a solid video for the average shadetree guy to explain how to fix it as cheaply and easily as possible at home.

Now of course there is plenty of debate about cheapest fix vs best fix and so on, and there are other items and ways to fix the P1870 error code. You can replace the whole gosh darn valve body for $100-200. You can put in one of various shift kits/repair kits for $40-$50 which include a new TCC valve but thats going to take more time because of more pieces than you need at the moment. If you have a high mileage vehicle like mine you may decide (as I did) that its not worth it to buy a valve body or go through the hassle of putting in a whole shift kit when you pretty much know the life of the bands and reaction shell or sunshell or SOMETHING or another is just going to break a few more miles down the road anyways. So if the transmission currently has no other issues except the P1870 slippage, how do we get it back on the road for the least amount of time and scratch?

Teckpak's A74741Q TCC VALVE is the answer. I got mine here for $12 4L60E Transmission TCC PWM Valve Repair Code 1870
Here is their site: P1870 CODE - TCC REPAIR VALVE for 4L60E from Teckpak / Fitzall

All you need besides that is a new transmission filter, a transmission pan gasket and a few quarts of new transmission fluid (and a handful of basic tools).

It has long been rumored and whispered that the Teckpak valve could be installed without removing the valve body, but details were elusive. Not having to remove the valve body is pretty much the tipping point between "yeah, a normal non-mechanic could fumble through that on his own" and "Hell no! Take it to a transmission shop and prepare to sell your firstborn!"

So without further adieu, here for all my fellow 96-99 S10 owners with notalotamonies and limping along their high mileage S10s, is how to install the teckpak valve and fix your error at home without removing the valve body:

Good luck!