Loss of mpg after getting stuck
I went hunting two weeks ago in Colorado. Towing my camping trailer possibly 2.5-3k pounds. Hunting camp is at 9500' When I got there I loss traction in the snow and had to put it into 4wheel drive. Trying to get out I noticed the truck jumping in place as I was giving it skinny pedal. Never notice this before in any of my trucks prior to this. Also I could smell something was hot when I got there. Not sure if that's coming from the tranny or the engine. I had changed the oil the night prior.
After I got unstuck and got moving again and at the camp site. I turned the truck around and went to back up and all I could get was black smoke to roll out and the truck barely apply pressure to the tires. I had to rock the truck to get it to back up. Once I got it to move if I let off the pressure, I would have to restart the process of rock the truck forward and back to get it to move again.
Now on the way out there I went up in elevation from SLC to Co. On I-80 cruising at 75mph or just under 2k rpm and averaged 15-16.5 mpg.
On the way back I went on I-40 which top speed was 65. N but probably averaged 55 mph and got 10. Mpg. Now that I'm home and unhooked at at my normal cruising weight. I'm only getting 11.5 mpg.
My question are, did I screw something up in the tranny when I was stuck? or is all that normal because of the elevation? Or is the oil change part of my problem cause I used rotella?
Truck has 200k miles on it now. PO said that he had the tranny rebuilt around 100k mark. Is this a normal 100k mile rebuil?
Any thoughts would be appreciated.