Transmission slipping in 4wd

[Barrow 171]

Hello everyone,
I have an 05 Yukon that we took out on the beach and the 4wd hi started to slip under the load on the sand and the truck wouldn't move. In 4 low it would but not as it should. No problems shifting or driving on pavement so i am assuming there is something wrong in the transfer case. Any ideas where to start would be greatly appreciated.
Thanks

 

[Fless]

Welcome to TYF!

Tell us a bit more about how the 4Hi "slips." Do the rear wheels spin but not the fronts? Kind of like it's in the Auto mode?

 

[swathdiver]

Hello everyone,
I have an 05 Yukon that we took out on the beach and the 4wd hi started to slip under the load on the sand and the truck wouldn't move. In 4 low it would but not as it should. No problems shifting or driving on pavement so i am assuming there is something wrong in the transfer case. Any ideas where to start would be greatly appreciated.
Thanks

Welcome Nick, please give us a little more info like Steve said.

 

[Barrow 171]

This past trip when we started out it was fine. When it started it felt like the truck was just bogging down and losing power in 4 high. The harder you hit the gas the less it did until it stopped and gave off a almost hot brake smell. In 4 low it would move but very slowly and not as it should. In 2 wheel it drove fine but in the deep sand 4 hi was needed.

 

[Barrow 171]

This past trip when we started out it was fine. When it started it felt like the truck was just bogging down and losing power in 4 high. The harder you hit the gas the less it did until it stopped and gave off a almost hot brake smell. In 4 low it would move but very slowly and not as it should. In 2 wheel it drove fine but in the deep sand 4 hi was needed.

Also there had been a couple of times over the past year when atart from a stoplight the the truck hesitated before taking off. I have used the truck to pull trailers and boats often and never had any problem with the drivetrain except for those two times and on the beach.

 

[swathdiver]

Also there had been a couple of times over the past year when atart from a stoplight the the truck hesitated before taking off. I have used the truck to pull trailers and boats often and never had any problem with the drivetrain except for those two times and on the beach.

I would inspect the brakes, specifically a sticky caliper or worn slides or guide pins. Truck is 15 years old, when was this stuff last serviced/replaced?

We had one piston on one side up front stick a few months ago, caused the steering wheel to shimmy. When we took it apart, the piston was out a little bit, pushed it back in, greased the slides and put it all back together and has been fine since. It had been about a year since we did them but calipers and hoses are original.