Shifting Problems

[xtruckerbob]

We have a 03 1/2 ton Tahoe with 5.3 and 343 gears with 130,000 miles on it which we I used to pull a car hauler and our Kubota locally which weighs 3500 lbs.. Ealier this year I bought a Ford 3000. When I started home with the tractor (about 6000 lbs) our Tahoe shifted back and forth constantly even on flat ground. I put it in "tow mode" with no different. When it shifts it goes almost to the red line stays for 1-2 seconds the shifts back to drive then in 1 minute repeats it. I pull the trailer in drive not over drive anyway. This is the only heavy load the truck has ever pulled. Is this common?

 

[jenkinsph]

Just guessing that engine rear ratio is good for about 5000 lbs maximum towing. You are looking at a 6000 lb tractor and trailer guessing 1800 lbs so a little over the limit for that Tahoe. If it does okay otherwise I would try to limit the heavier trailer towing to a minimum.