I bought a new trailer the other day. It's 18' long and I believe it weighs around 4000 lbs. When I pulled it home it had a 5' brush hog and a set of double row plows that I had also purchased, shouldn't be a problem for my powerstroke to pull right. Well I started off in tow/haul mode and when I got the truck up to about 60 mph the truck started jerking like it was trying to shift but it had already shifted thru all of the gears ( it's an automatic 2002 ). I shifted it out of tow/haul mode and it seemed to straiten up but when I got up to 70 mph it started doing it again. As long as I would stay below those speeds it did good seemed to shift good I'm not sure if this is a tranny problem or not. Any help would be greatly appreciated.

 

There is no tow haul mode on the 7.3... only a OD lock out...

Sounds to me as if your TC was locking and unlocking.

How many miles on the truck? Any mods or gauges?

 

Truck is stock with 94000 miles

 

Sounds like the tranny is going out. I would guess it has some issues with the shift pack...