krybolt

Been doing some research on my truck problem. Went into autozone, got my cel checked, P1870. Also has the very very hard shift from 1-2, 2-3 after 30 minutes or so of driving. Heard its most likely from the tcc valve and all that. Read that the transgo shift kit for the 4l60e will fix the problem (along with the sonnax, but heard the transgo is just as good and easier to install)

Would this be the correct shift kit for it?

TRANSGO 4L60E 4L60-E SHIFT KIT GM CHEVY TRANSMISSION TAHOE YUKON ESCALADE | eBay

Any reason to not buy the shift kit and go with the sonnax kit, even though I would have to take it to a shop to do??

Thanks in advance for the replies!

Camaro 69

Transgo's description on their website says "fixes code 1870". And the other fix for the shifting is what you're describing with your truck, with the exception of you also having a hard 2-3 shift. Transgo is a good name for shift kits, I wouldn't hesitate using it.