GM's 2020 tow rating question for all

4x4ord wrote:

Huntindog wrote:

Cummins12V98 wrote:

FishOnOne wrote:

Cummins12V98 wrote:
The answer is they could not pass the SAE test at any larger weight. My reason was the Allison 1000.

If you watched the video I posted last week the GM engineer was asked what did they do to improve the towing capacity by ~10k lbs and the engineer stated they improved the cooling system, rear axle, and drive train (place Allison transmission here).

2020 GMC

Repeated hill starts would be the reason. Fact is the rear end is now a 3.42 and before it is as 3.73. Maybe stronger but not as easy to move the load unless first gear in the NEW trans is lower.

Ummmm... That would only be true, if GM were to attempt this test with 3.73s Here is where I point out that neither Ford or RAM passed that test at higher weights with 3.73s Must be because their trannys were weak?:B:E

Go back and reread my post.

And realize that if GM had been able to just put in a 4.10/4.30 gearset as Ford and RAM did, that they would then be able to move heavier loads with out increasing the stress on the tranny one bit.

I agree that a 4.10 rear end would allow an older Duramax to tow more but, I don't see how the transmission is going to care a whole lot what rear end is behind it. If the engine and transmission are coupled to a 3.42 and the driver floors it the engine will put all the torque it can to the transmission's input shaft .... the transmission will multiply that torque by the gear ratio and the resultant torque will be applied to the out put shaft. If you remove that 3.42 rear end and install 4.10 gears the torque on the transmission's input and output shaft will be identical. I suppose in light duty applications where on;y part throttle is necessary the 4.10 rear end would require less throttle and would therefore put less stress on te transmission but in light duty applications the stress is not an issue. All I'm getting at is that if the tranny can't handle a 25000 lb trailer under full throttle it can't handle a 15000 lb trailer under full throttle..... it can't handle full throttle.