650mi surge

[856.9]

I took the truck for about a 120 mile drive today. First time I've had it in the mountains, so I used the tow haul mode. Because most of the driving was about 35-40 mph in some traffic. Once I got out a bit farther I turned off the tow haul and could run 50-65. About a mile after I turned it off the truck started to surge for about 5 seconds climbing a hill. I wasn't sure if it was the truck or road so I didn't worry about it. A few miles later it did the same thing. I pulled over and didn't see anything wrong so I finished my drive, about another 50 miles, without any problems.

Any ideas? I've read some posts on surging and it sounds like it's hard to duplicate and that dealers aren't much help. The truck goes in on Wednesday for new running boards and a power slider. Should I tell the dealer? I don't want to let them keep it overnight or a few days just to tell me there's nothing wrong.

Thanks

[tpace]

Was the truck in overdrive, around 60 mph, just before a downshift?

[856.9]

Going less than 50, transmission selector was in OD stepping on it caused it to go away. I've read some other posts that make me think maybe it was lugging.