The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

Rich84 · 07-10-2017, 01:34 PM

Truck is back on the road...

Replaced the transmission with a good unit that I had in one of my other trucks. Immediately thru a code and was stuck in 2nd and 3rd again. After I calmed down, I started checking the wiring. I didn't see anything out of order at the transmission. So I went to the ECM to start tracing wires. What I found was that the large connector at the ECM was not fully seated properly. The only condition that it caused was the transmission problem I was experiencing. No other issues.
Transmission shifts beautifully and I couldn't be happier with the swap.

07-10-2017, 01:34 PM	#18
Rich84 Registered User Join Date: Mar 2012 Location: Woodbury, Ct. Posts: 1,668	Re: 4l80e No Overdrive Truck is back on the road... Replaced the transmission with a good unit that I had in one of my other trucks. Immediately thru a code and was stuck in 2nd and 3rd again. After I calmed down, I started checking the wiring. I didn't see anything out of order at the transmission. So I went to the ECM to start tracing wires. What I found was that the large connector at the ECM was not fully seated properly. The only condition that it caused was the transmission problem I was experiencing. No other issues. Transmission shifts beautifully and I couldn't be happier with the swap.