Another Win For GM's HD's
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DeereMann
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:stirthepot:
aczlan
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Good for them if the specs were truly the same, but I will be suspicious until they get around to releasing the exact specs on these trucks.
They said "similarly spec’d" trucks, but if the GMC had 4.10 gears while the Ford and Dodge had 3.73 or 3.55 gears it would be easy for the GMC to "pull away" from the Ford and Dodge...
Sent the editor an email asking what the specs were.
Aaron Z
They said "similarly spec’d" trucks, but if the GMC had 4.10 gears while the Ford and Dodge had 3.73 or 3.55 gears it would be easy for the GMC to "pull away" from the Ford and Dodge...
Sent the editor an email asking what the specs were.
Aaron Z
roadhunter
Elite Member
That Allison is a excellent transmission, Too bad you have to put up with the rest of the truck to get it
Exactly.
OP
Paystar
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Yes, I'd still like to have a Superduty with a Cummins motor and Allison trans.
But I highly doubt Ford will ever get me back.
But I highly doubt Ford will ever get me back.
Ken45101
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That Allison is a excellent transmission, Too bad you have to put up with the rest of the truck to get it
Hmmmm. I have only had to have a vehicle towed three times in 50 years. TWO times were the only Ford that I ever owned (F250). Both were well known (to the service department) problems.
dodge man
Super Star Member
The test is a joke. They used the 250 version of the truck since that was the version they knew GM would win. Take the same trucks and get the top dog version of the Ford and the Ram and see what happens with a 20,000 lb load behind them. These tests always have a known outcome ahead of time.
handirifle
Veteran Member
Unless that truck was modified for that test, and unless GM has changed their policy, the 2500HD Diesel is ONLY available with 3.73 gears. There are (or at least were) no other gears available.
If you want to test "identical" vehicles, then test 3 Fords or 3 Dodges etc, cause that's the ONLY way they will ever be identical. Even with the same axle ratio, are the lower tranny gear ratios identical? I seriously doubt it. In addition, there's tunes the mfg's work with to broaden power curves etc.
The programming of the Allison TCM (transmission control module) might have been enhanced to compliment the new tune GM has given the 2015's. An article in Diesel World states that due to improved cooling for the engine, they were able to modify their tune for the engine, and provide broader power. The numbers are the same, but if the engine hits peak torque of 765 (I believe) at 1600 rpm, it MIGHT not fall off till say 2200 or 2300 or maybe higher. That would be a HUGE advantage.
In addition, the variable geometry turbo might come on quicker as well. There are SOOOOO many variables in a test like this the truck will NEVER be identical, unless they are made by the same company. Even then I have seen high output engines that were factory identical, and one produces 20 more HP than the other.
For a 2500 (or 250) 3.55 gears would not seem to bright from a marketing stand point, for a diesel truck, that someone is buying to actually haul with. Now on the 1500, it makes sense to me, since someone would be more likely to "occasionally haul" and better mpg would be more desirable.
If someone discovers something that made it unfair, then slam the crap out of GM otherwise I take it at face value. I am sure the GM did not outdo the others in all categories.
handirifle
Veteran Member
Actually, if one reads the article, the GM rep pretty well explains why.
....................
Product manager Craig Couch credited the six-speed Allison transmission with giving the Sierra HD the edge. Allison builds what are truly heavy-duty transmissions; the ones found in the Sierra and Silverado would be among the smallest it produces. Because this product was over-engineered for pickup applications, it requires less torque management, meaning it can deliver 100% of the torque produced by the engine right to the wheels.
Horsepower and torque, as displayed on price sheets or proclaimed on advertisements, is measured at the engine and not where the rubber meets the road, which Couch said can be misleading.
“The weaker link of the Ford and the Ram would be their transmission, so they torque-manage,” Couch explained. “They pull fuel in first and second gear to prevent heat buildup, or too much torque for the transmission to handle at a given step in the transmission where it could do some damage. So they put a calibration in, where they’re not utilizing all the torque and horsepower that’s available to the transmission. We don’t torque-manage to the extent the competition does, because the Allison transmission is more than capable of handling the torque demands the Duramax engine puts out. We feel the weak link in the competitors’ drivetrains is their transmissions and it’s the strongest link in ours. Our truck has the lowest stated torque of all three competitors but it actually out-accelerates the competitors because we don’t have to torque-manage and you’re getting all the available torque to the wheels, all the time.”
....................
Product manager Craig Couch credited the six-speed Allison transmission with giving the Sierra HD the edge. Allison builds what are truly heavy-duty transmissions; the ones found in the Sierra and Silverado would be among the smallest it produces. Because this product was over-engineered for pickup applications, it requires less torque management, meaning it can deliver 100% of the torque produced by the engine right to the wheels.
Horsepower and torque, as displayed on price sheets or proclaimed on advertisements, is measured at the engine and not where the rubber meets the road, which Couch said can be misleading.
“The weaker link of the Ford and the Ram would be their transmission, so they torque-manage,” Couch explained. “They pull fuel in first and second gear to prevent heat buildup, or too much torque for the transmission to handle at a given step in the transmission where it could do some damage. So they put a calibration in, where they’re not utilizing all the torque and horsepower that’s available to the transmission. We don’t torque-manage to the extent the competition does, because the Allison transmission is more than capable of handling the torque demands the Duramax engine puts out. We feel the weak link in the competitors’ drivetrains is their transmissions and it’s the strongest link in ours. Our truck has the lowest stated torque of all three competitors but it actually out-accelerates the competitors because we don’t have to torque-manage and you’re getting all the available torque to the wheels, all the time.”
