I have a 2010 GMC Sierra 1500, 44Kmiles, and the last few days I start to notice that on the highway, the tach will slip around between 2 and 4K rpm's when I accellerate.

I use the truck as my daily 50 mile commute to work, regualr oil changes, and moderate weekend towing (it has the tow package) for a trailer that holds 3 quads.

This morning, on my way in, I messed around with driving in tow mode, adn it seems the issue might go away when I do this, but probably coincidence.

Anyways, could my tranny be going already?

JJ in Pittsburgh