Have a 2008 H3. Considering purchase of Airstream travel trailer with a total weight of around 5,200 lb and hitch weight of 750 lb. I know this is well above vehicle ratings of 4,500 lbs and 500 lbs, respectively. No towing is planned in hilly or mountainous areas, just flat coastal settings and short trips where speeds could be kept low.

Main area of concern would be the transmission. Does anybody have any experience with any type of gauge/monitoring set-up to keep an eye on transmission fluid temperatures? If so, any feedback on what you used to track transmission temperatures would be appreciated. I've also been told that the factory transmission cooler should be up to the task of keeping temperatures in check, but I'm not so sure.

Lastly, does anyone have experience running a weight distribution hitch on your H3? If so, were any complications encountered?

My hope would be that keeping things slow and steady, say 45 -50 mph, would be doable.

Thanks for any thoughts/feedback.

 

I am not sure the Scan Gauge II can monitor Trans temp on the 08+, it can on earlier H3s.

I towed a boat back to SE MI from WI, about 430 miles one way using the OEM class III hitch. The boat was 4200# and the tandem axle trailer about another 1100#, and my truck has performance mods. After getting through Chicago rush traffic stop and go, I ran 65 -70 right on the behind of an 18 wheeler (I got permission to pack it back there over the CB) all across MI, but I would not recommend it. With the short H3 wheelbase, you get some tail wagging the dog feel on big bumps and down hill runs. The tranny was HOT!, and it was a cool day in the upper 60s.

It got it done, but I won't be doing that again. At a minimum I would suggest an add on Trans Cooler for that load.

 

I would be worried getting in an accident and the insurance company finding out you were way overloaded. You might not be insured then.

 

I agree. You would not be covered under your insurance in an accident. But more importantly every time you tow overloaded you are doing damage to your vehicle. The damage may not appear immediately, but you are shortening the life of many many parts. The things that are damaged most in overloaded towing are the transmission, brakes, rear differential, and suspension. I would never tow overloaded. First of all it is dangerous, to you and to other drivers, and it is also terrible for your Hummer.

 

With a conserv. est. say 10% that gm' legal egals demin. the overall tow value and the 4l60e being a
very stout tranny, the strength is probably there. The challenge at this point will be gear hunting and nose pointing to the sky.
I tow daily with Happy Hummer and it does gr8. Diff is one 4th the wieght. That is iffy enough. The wheel base is really quite good.
Chris