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2020 GMC HD

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View attachment 55781

I am curious to see how this new truck runs with a 10 speed Allison. Fuel mileage? Power?
It's NOT an ALLISON transmission. It is an ALLISON APPROVED/CERTIFIED transmission designed by GM/FORD, and GM paid ALLISON to test and certify so they could slap the ALLISON name on it as a selling point. Only the 4500/5500 get an actual ALLISON trans which is still a 6 speed. This trans is the same as the 10r140 that FORD is putting into there new 2020 HD truck.

I'm not saying anythi,g is wrong with it because so far the reports on the FORD/GM collaboration transmissions has been good. I just don't like the sneaky tactic used to keep the ALLISON name for sales.
 

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Found some info on another site. The 4x4's will be autotrac now instead of just a part time case. Gearing is supposed to be changing to 3.42 with the DURAMAX and the new 10 speed "ALLISON" instead of the old 3.73. Lockup now in 1st gear instead of 2nd+. The rear axle will be a 12" instead of the 11.5"(most are thinking its the 11.8" that they use in the DODGE dually with the aisin trans). And an all new chain driven pto that runs at actual engine speed.557975579855799
 

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I wonder how the 10 speed tranny will hold up against the 6 speed. Will gears be just as strong? Will the more powerful engine eat up the metal gears? Max RPMs on highway in 10th gear?
A whole bunch of stuff in there to repair if there is a major failure....😬

Yes how durable? That chain driven PTO is running all the time I assume, could we have chain issues at some point when things get worn.

I know very little about transmissions, just pondering on the subject.
 

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A few more pictures and info on the 2020 GMC.

https://www.motortrend.com/cars/gmc/sierra-2500hd/2020/2020-gmc-sierra-hd-first-look-review/

 

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I wonder how the 10 speed tranny will hold up against the 6 speed. Will gears be just as strong? Will the more powerful engine eat up the metal gears? Max RPMs on highway in 10th gear?
Nobody knows yet. The 10r140(Ford)/10l100(GM) has yet to be seen by the average joe. It is a little concerning that GM stayed with the allison 1000 6 speed for the 4500/5500 that they're building with INTERNATIONAL(Navistar's way of getting back at Ford for dropping them for engines). I did read the new transmission will be able to shift MUCH faster than the allison, and unlike the allison it can skip over gears downshifting.

If they do in fact run 3.42 gears, they should drop right down in 10th gear as the other 10 speeds have a .64:1 10 the gear(or 3rd OD gear). They also have a 4.71 1st gear with lockup in 1st, so if they run those ratios, it should pull right out. GM has also eluded to saying this one will have full power available in all gears(unlike the current model that is torque limited in 1st).
 

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Nobody knows yet. The 10r140(Ford)/10l100(GM) has yet to be seen by the average joe. It is a little concerning that GM stayed with the allison 1000 6 speed for the 4500/5500 that they're building with INTERNATIONAL(Navistar's way of getting back at Ford for dropping them for engines). I did read the new transmission will be able to shift MUCH faster than the allison, and unlike the allison it can skip over gears downshifting.

If they do in fact run 3.42 gears, they should drop right down in 10th gear as the other 10 speeds have a .64:1 10 the gear(or 3rd OD gear). They also have a 4.71 1st gear with lockup in 1st, so if they run those ratios, it should pull right out. GM has also eluded to saying this one will have full power available in all gears(unlike the current model that is torque limited in 1st).

Does that mean when one stomps the go pedal to the floor empty, there could be some tire smoking going on??? :smuggrin:
 

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Does that mean when one stomps the go pedal to the floor empty, there could be some tire smoking going on??? :smuggrin:
The 4X4 with autotrac most likely won't as I believe it is full time all the time. With the 2 wheel drive, who knows. The 2 wheel drive may be torque limited, it may not. I do know several have complained the traction control never fully shuts off in the newer trucks, so who knows.

It's still yet to be known wether or not the ECM will remain the same, or if GM will try and switch things up again since people have now found a way around the security.
 

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Found where somebody posted the gear ratios, and posted up the final drive numbers for them for the allison with 3.73's, and the new "allison" with 3.42's. Not much difference between 6th in the allison vs 10th in the new one, but look at the difference down low.

1st 3.094 - 11.540
2nd 1.809 - 6.747
3rd 1.406 - 5.244
4th 1.00 - 3.730
5th .711 - 2.652
6th .614 - 2.290
R 4.48 - 16.710


1st 4.54 - 15.526
2nd 2.86 - 9.781
3rd 2.06 - 7.045
4th 1.72 - 5.882
5th 1.48 - 5.061
6th 1.26 - 4.309
7th 1.00 - 3.420
8th .85 - 2.907
9th .68 - 2.325
10th .63 2.154
R 4.54 - 15.526
 

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Serious grunt for sure taking off.

Chevy is claiming to tow more weight, but all Ford has to do in the new truck is put a rear end gear close to 3.73 or 3.90, heck the 4.30 gear, then what advantage does GM have?
Maybe I am missing something, but both GM and Ford are sharing the same 10 speed, supposedly. The advantage of the 6 speed Allison transmission GM had over Ford is gone?
 
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