2020 GMC
Well maybe the truck builders are finally listening to the RV crowd for a change: Just got a brochure on the 2020 GMC HD trucks. 1. They have finally made the bed rails lower 2. They have a ...
Forum Discussion
Cummins12V98 wrote:You like to state that a lot.... It shows a lack of understanding ot the effect a lower rear axle ratio can have.Grit dog wrote:
" If Ram had access to a 10 speed they would have one in their pickups right now."
Eggzactly! Except the blind fanboys will tell you how 6 cogs is better than 10 because.....
Waiting for Ram to get the 8 speed ZF powerline trans. That should level that playing field.
Have I criticized GM because they would not admit the strength of their 6 speed was not op to the task and gave a LAME excuse of why their DRW could only pull 23,700#? HE!! yea!
A 4.10 gear in place of the 3.73 would allow it to tow more weight without any more stress on the tranny... So why did GM not do it?
I was told by a long time GM engineer years ago, that when they tried 4.10s behind the D/A that the pinion would not hold up.
At the time I did not give this much thought.
Having some experience with setting up ring and pinions, I KNOW that as you go to lower ratios, the Pinion contact area becomes smaller and weaker... This is a fact.
So if one takes a look at what GM did to increase the tow rating, it is enlightening.
They increased the size of the ring and pinion, AND installed taller gears. This has the effect of making the rearend gears MUCH stronger. The 10 speed tranny allowed them to do this as the necessary torque multiplication can now take place in the tranny, not the rearend.
So why were Ford and Ram able to just swap in lower gears in the pumpkin, raise the tow rating, and call it good?
Probably because the Dmax which was the ONLY one to dyno according to demanding SAE protacols actually put out more power, than their competiters (despite their higher "advertised" ratings).
As for the test results.... First off there is the speed limit of 60MPH, Then there is the fact that they went by the speedometers to determine this.. One truck said it was 7.9 miles, the other 8.1, so there is some error there. Small but important in this test.
Both trucks easily were able to move 16K up the hill. So with the speed limit, the speedometer error, and the ease that both trucks were able to handle that weight, it just isn't possible for one truck to beat the other by a large margin.
Increase the speed, or weight, or both.... And the test would be more demanding, and I think a clear winner would be obvious
