Engaging 4 wheel drive on 2010 GMC 2500 HD Truck

Hello Car Talk People,

I’m asking this question on behalf of my boyfriend. His only interest in engagement has to do with his 4 wheel drive GMC 2500 HD Truck. He wants to know the correct procedure for 4-wheel drive engagement. What would be the max allowable speed for engagement? He only wants to know High engagement only. Can you please answer this question ASAP cuz I want to discuss other engagement issues with him. Thank you.

All that information should be in the manual, look it up!

Not helpful. If we had the manual we would have looked it up. The manual is Shanghaied at the dealership where it has been wasting away under the incompetent management of the dealership people (Allen Samual’s Chevrolet).


I have never had to do high speed on the fly 4wd engagement, 4 lo for the trailers extremely rarely, 4 hi If WI weather or construction sites demand it at the beginning of the trip. Sorry I can’t help more.

The dealer may let you read one from another truck.

Chevrolet has the manual online. 4wd is on page 3-36.



Ed B.