MBay Mobey
TYF Newbie
Long time lurker, first timer poster. 2016 Tahoe LT, original owner.
I’ll start by saying I had my 2016 Tahoe serviced by the Dealer in January at the 95K mile mark since my battery died. The Service Dept performed the 100K mile scheduled service. After I picked up my Tahoe the transmission seemed healthy and shifted well. A few weeks later I noticed that the vehicle seemed to be “mis-firing” or slipping gears between 3rd and 4th. A friend of mine said i needed to perform the “transmission re-learn” step after replacing the battery, this was news to me. So I found the procedure on YouTube and followed the steps on the video. This did not correct the problem.
On my next 400 mile roadtrip to visit the grandkids I closely monitored the engine and transmission behavior. I noticed that the engine rpm’s would swing +/- 200 rpm while maintaining steady speed, even in cruise control. I took the vehicle back to the dealer and asked them to check the transmission out. The Service Mgr said the vehicle was not throwing any codes and the only thing they found was low primary fuel pump pressure. So for over $1K they replaced the primary fuel pump. I drove it to So Cal the next day and the vehicle was still behaving the same (mis-shifts, varying rpms). The transmission temp never got over 195 deg.
I called a few Transmission shops who seemed familiar with the 6L80 transmission problems. I described the symptoms and was told that my Torque Converter was likely failing. One very knowledgeable shop asked if I was getting the “washboard shudder”. I had not felt that yet, but he said that was indicative of TC failure.
I added a tube of “Lube Gard” to the transmission on my last trip to So Cal, and on the way home I definitely started to the feel the washboard/shudder. Had the Tahoe towed to the shop once I made it home. Made the choice to re-build my tranny instead of installing a “re-manufactured” unit. Billet Torque Converter, Sonnax Zip Kit, Borg Warner clutches, Superior STL010 Sure Cool valve, and other upgrades recommended by the shop, less than $4,500 out the door.
The Tahoe runs great now, shifts solid, and on my last trip through the Central Valley the transmission never got up to 150 deg, even though it was over 100 deg outside.
I’ll start by saying I had my 2016 Tahoe serviced by the Dealer in January at the 95K mile mark since my battery died. The Service Dept performed the 100K mile scheduled service. After I picked up my Tahoe the transmission seemed healthy and shifted well. A few weeks later I noticed that the vehicle seemed to be “mis-firing” or slipping gears between 3rd and 4th. A friend of mine said i needed to perform the “transmission re-learn” step after replacing the battery, this was news to me. So I found the procedure on YouTube and followed the steps on the video. This did not correct the problem.
On my next 400 mile roadtrip to visit the grandkids I closely monitored the engine and transmission behavior. I noticed that the engine rpm’s would swing +/- 200 rpm while maintaining steady speed, even in cruise control. I took the vehicle back to the dealer and asked them to check the transmission out. The Service Mgr said the vehicle was not throwing any codes and the only thing they found was low primary fuel pump pressure. So for over $1K they replaced the primary fuel pump. I drove it to So Cal the next day and the vehicle was still behaving the same (mis-shifts, varying rpms). The transmission temp never got over 195 deg.
I called a few Transmission shops who seemed familiar with the 6L80 transmission problems. I described the symptoms and was told that my Torque Converter was likely failing. One very knowledgeable shop asked if I was getting the “washboard shudder”. I had not felt that yet, but he said that was indicative of TC failure.
I added a tube of “Lube Gard” to the transmission on my last trip to So Cal, and on the way home I definitely started to the feel the washboard/shudder. Had the Tahoe towed to the shop once I made it home. Made the choice to re-build my tranny instead of installing a “re-manufactured” unit. Billet Torque Converter, Sonnax Zip Kit, Borg Warner clutches, Superior STL010 Sure Cool valve, and other upgrades recommended by the shop, less than $4,500 out the door.
The Tahoe runs great now, shifts solid, and on my last trip through the Central Valley the transmission never got up to 150 deg, even though it was over 100 deg outside.
