Why is Towing limit lower on Manual?

[BEST 4x4xFAR]

Okay,
So the Automatic is rated to tow 4,500 lbs, but the manual only 3,000 lbs. Same vehicle otherwise, so why the significant discrepancy in tow ratings? Is it because the manual gearbox is already marginal for the application (input torque rating of 225 lbs/ft, and the engine is rated for a max of 225 lbs/ft -- What are they doing for '07 manuals by the way)? 4,500 lbs is already low compared to its completion, but 3,000 lbs is just plain sad. Anyone know for sure why GM underrated the Manual by 1,500 lbs?

[f5fstop]

Aisen AR5 manual trans. Same as what is going into the 07.

[evldave]

Originally Posted by BEST 4x4xFAR

Okay,
So the Automatic is rated to tow 4,500 lbs, but the manual only 3,000 lbs. Same vehicle otherwise, so why the significant discrepancy in tow ratings? Is it because the manual gearbox is already marginal for the application (input torque rating of 225 lbs/ft, and the engine is rated for a max of 225 lbs/ft -- What are they doing for '07 manuals by the way)? 4,500 lbs is already low compared to its completion, but 3,000 lbs is just plain sad. Anyone know for sure why GM underrated the Manual by 1,500 lbs?

Basically, I disagree with everything you are bitching about.

4,500# for a mid-size is quite good. Cherokees were rated at 5k and 3.5k (auto/man) and I can absolutely say they were overrated (trust me, I pulled a 4000# trailer w/my 5 speed, scary $hit).

I'd guess, with it's curb weight, the H3 could pull (not endorsing anything here) at least 6k pounds w/o safety issues, wire a trailer brake and maybe more. You wouldn't go fast, but my experience towing has been there is a difference between safe (way over the factory rating) and fast (less than the factory rating).

There are many people here who have towed w/their H3 regularly and haven't had problems. The H3 drivetrain is mostly made up of full-size equipment (tranny, difs, etc). Do you have a trailer that weighs more than 4700 lbs? If so, maybe you should think of a dedicated tow rig, if it's less tha 4,700 lbs (say a camper trailer, small car hauler, quad trailer, etc) it will be fine and quit bitching about numbers on paper and go drive it!

[BEST 4x4xFAR]

Well, sorry If I offended you evldave,

However, many mid size vehicles have higher tow ratings, and those available with manuals do not seem to vary by transmission (FJ Cruiser, Xterra both rated at 5,000 lbs). Some have significantly higher ratings (Touareg, Cayenne, LR3 are rated to 7,700 lbs, Pathfinder, Grand Cherokee to 6,000 & 6,500lbs respectively). Disagree if you want, but the numbers are the numbers.


Seems to me the H3 would be a good towing platform up to around 6,000 lbs (with the exception of engine power) given its wheelbase and curb weight, and I don?t understand the significant de-rating for the manual transmission, unless it is for concerns about the gearbox?s strength (which honestly concern me a bit given its specs). So here we agree evldave (6K probably safe), (and though this is another topic altogether) but the problem is if I tow a 3,001 lbs trailer with a manual H3, and I am involved in an accident (even if it is not my fault), somehow it will become my fault in court because I was exceeding the manufacture?s recommended towing capacity and was therefore being unsafe.

But back to the original question, why the de-rating for the manual. I could live with the 4,500 lbs rating (though 5K would be better), and feel the H3 with a manual would be just as safe to 4,500 lbs as an auto (caveat explained above though). I?m not sure how this question is ?bitching?, I think it is valid, and whether you want to accept it or not, pretty much all of the H3?s competition I can see is rated to tow more, significantly more in some most cases (for example, even though the FJ and Xterra are only rated for 500 lbs more as autos, they are rated for 2,000 lbs more as manuals. And personally, as someone who has done some towing, I find this to be a significant difference).

Fstop,

I see that GM is using the Aisin AR5 (or GM?s coding MA5 I believe) for the H3. I was just curious if they were modifying this gearbox for use in the ?07?s at all. Seems like Aisin would not warrantee this gearbox behind an ?07 3.7 liter engine, since it exceeds the AR5?s input torque rating of 225 lb/ft. Even in the ?06, it is cutting it pretty close using a transmission with an input torque rating the same as the engine?s maximum torque rating, don?t you think (be warned if anyone is supercharging a 5-speed)? I don?t think I have ever come across this in the past, generally the gearbox input rating is some % higher than the engine?s output, so I was curious if GM engineers saw this as a potential week spot, and reduced the tow rating as a result.

[PARAGON]

The answer is pretty simple and is not specific to GM. All manufacturers lower the tow ratings on the same vehicle where the only change is from an auto to a standard tranny. It's due to the clutch.

They are not tow vehicles and towing significantly increases the wear on the clutch.

[Hummer Guy]

Originally Posted by BEST 4x4xFAR

(Touareg, Cayenne, LR3 are rated to 7,700 lbs, Pathfinder, Grand Cherokee to 6,000 & 6,500lbs respectively). Disagree if you want, but the numbers are the numbers.

I'd go for the Touareg...

[usetosellhummer]

WTF Hummer don't tow good we all know that. Get a Duramax GMC if ya need to tow.