I was recently pulling the boat(3k-4k) out of the lake from a private ramp, in northern Tennessee, needless to say it was steep, I put in 4 low and easily walked out at 1,200 RPM. The ramp approximately 500' to the road, straight shot, bottow was gravel and the top 200' was concrete.

While one the concrete the truck would lunge, it did this 3 or 4 times. I know the 4x4 will bind on dry hard surfaces like this, but I was going straight, does this sound like a normal thing ir the transmission slipping?

 

If you were going straight then I would say that the trans is slipping!! The TQ Converter might need to be replaced! Good Luck!

 

Sounds normal 4x4 on hard service to me.Even straight.

 

i recently had a similar problem at slow speed the truck felt like it was surging looking for a gear sort of thing. Took it to the dealer and they thought it might be a sticky throttle body sensor in the tranny .They replaced it and i've had no trouble since.This problem only happened three times in 30k but it was obvious it was not normal so it may be similar to your problem.

 

Ditto - 'cause the front & rear tires are rarely worn the same amount...

 

Yep and rough surface/conditions etc.The owners manual states not to use on HARD surface.Dosen't say straight line is ok.I would expect it to be a little jerk/grab/wheel slip etc.Will also do that on hard baked ground also.