My truck has 123K miles on it. The transmission is a 6 speed 6L80. About a month ago I was towing a 23' 8'6" beam, 5000 pound ski boat about 300 miles. The transmission temp maxed out around 193. About 100 miles before our destination the check engine light came on. It was late and we were going through small towns so I did not have a chance to check the code. I was in tow haul mode and never noticed any issue. The next day the CEL was gone.
Yesterday I was driving around unloaded and had the truck fail to shift and rev up to 3K+ rpm. At that time I noticed that the CEL was back. I was half a mile from home. I do not believe that it shifted on the way home, it seemed to be locked in gear.
Once home I stopped and restarted the engine. After restarting the CEL remained but the transmission seemed to function normally. Later I drove 15 miles into town to have the code read. The codes were P2715 and P0700. I did not ask to have the codes cleared.
I have had an issue with the 1st to 2nd or 2nd to 3rd shift where it seems to be a delayed shift with some revving between for years. This seems to happen when I am not accelerating hard or loaded.
Today I drove about a 25 mile loop to talk to a transmission guy I know and take the kids for a snack. On the way I shifted manually up and down through the gears. It shifted smoothly. On a short divided highway section I floored it to accelerate. It downshifted twice. The first was smooth and good. It seemed to have some free revving with the second, although I may just be overly critical about this.
The transmission fluid was changed approximately 10K to 15K miles ago.
I am hoping that others can share their experience with and solutions for similar issues with this transmission. What do you guys suggest?
Thanks in advance.
Edited by BruceW, 13 July 2013 - 03:12 PM.