My 2006 with auto had the fluid & filter service at 102,000 end of june. When driving up to Vermont at the end of aug.104,600 miles. we had a traffic tie up and crept along for nearly an hour. The car started slipping from 1st to 2nd. Car had been driving for about 3 hours. We finished our trip over 1,000 miles with no further occurance. Drove to Pittsburgh area and back twice over mountains about 700 miles no problems(other than the brakes are shuttering again)! This Saturday we drove up to Utica NY on route 81 about the same place under the same conditions (creeping along in traffic) same problem again 106,000 miles. Once we cleared traffic no problems since in variable driving; local stop and go return from New York etc.

 

Wonder if your trans cooler is working??? Overheated trans fluid??? Maybe even a little low???

 

What was coolant temp. in traffic tie up ? Was coolant fan on ? Have fluid level checked.

 

Wouldn't be too surprised that the fluid became overheated enough to burn it, its easy to overheat an auto transmission in a traffic jam. If you're in a stop and go creep along situation, knock the trans into neutral or park when you are sitting for long periods, you'd be amazed how just sitting still in drive can raise the fluid temps.

You may want to have the fluid changed again as a precaution, its an expense for sure, but compared to rebuilding the transmission in 15-20K miles...its cheap.