2017 GMC Sierra 2500HD Transmission Repair Scottsville, KY

This 2017 GMC Sierra 2500HD came to us from Scottsville, KY with a big problem, no forward movement at all. The truck would go into reverse just fine, but put it in drive and nothing happened. That right there was our first big clue.

In our experience with the 6L90 transmission, when a truck has reverse but no drive, there’s a common issue that pops up: a shrunken or stuck checkball in the spacer plate inside the valve body. And sure enough, once we got the valve body out of the truck, we found exactly that. One of the checkballs had shrunk and gotten lodged in place, blocking fluid from flowing where it needed to go.

Here’s what we did to get the Sierra back on the road:

✅ Removed the valve body and replaced the damaged checkball

✅ Replaced the pressure switches inside the TECHM while we were in there

✅ Completed a full transmission service for good preventative maintenance

✅ Reassembled and verified forward gears were fully functional

✅ Tuned the transmission to firm up the shifts, reduce slippage, and extend the life of the unit

Once everything was back together, the truck drove like it should. Smooth shifts, no hesitation, and forward movement fully restored. A small part caused a big issue, but by catching it early and adding a little preventative work along the way, we were able to save the customer from a much more expensive repair down the road. Many shops don't even realize this is a issue and may replace the entire transmission when they come across this!

If your GMC Sierra or 6L90-equipped truck is acting up, give us a shout at Wholesale Transmission Center. We know these units inside and out and are happy to complete any transmission repairs you may need!

Location: Scottsville, KY