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New ZF trans for 2023?

jsalbre said:
There’s a reason that semi trucks have 18 speed transmissions. With the short rev range of a diesel having more gears can only be a benefit, assuming of course that they’re spaced correctly.
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Uh huh. Do you know what that reason is?
 
jsalbre said:
There’s a reason that semi trucks have 18 speed transmissions. With the short rev range of a diesel having more gears can only be a benefit, assuming of course that they’re spaced correctly.
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That is the worst comparison… a 10 or 13 speed tractor trailer is almost more common on the highways they dont need the 18 speeds unless they are hauling 100k through the mountains. Most 18 speed tractors on the highway get used as an 8 or 10 speed anyway no good driver is going to split the lower gears and when they get to the high range they still only split the last couple gears…. Also comparing a manual trans to an auto is never a good comparison the auto tractor trans are usually only 10-13 speeds and thats moving 80k typically so in the grand scheme of things 6 speeds are plenty for these trucks especially considering ram still holds the highest tow rating against 2 10 speed trans trucks…
 
gimmie11s said:
Uh huh. Do you know what that reason is?
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The torque band of a diesel has a narrow range of RPMs and having more gears allows it to say in that ideal torque band.

It is s true that drives skip gears. However, if the terrain (mountain passes & large hills) dictates most will be used.
 
dieselscout80 said:
The torque band of a diesel has a narrow range of RPMs and having more gears allows it to say in that ideal torque band.

It is s true that drives skip gears. However, if the terrain (mountain passes & large hills) dictates most will be used.
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Yea if pulling 100,000lbs…
 
I understand the Cummins has gobs of torque for days...but I feel like the gear spacing of the 6 speed still leads to situations where one gear might be too short and the next gear might be too tall. Yes, it depends on how much you're towing.
Plus, I would feel much better towing lots of miles if I had a ZF trans vs the 68rfe.
 
dieselscout80 said:
The torque band of a diesel has a narrow range of RPMs and having more gears allows it to say in that ideal torque band.

It is s true that drives skip gears. However, if the terrain (mountain passes & large hills) dictates most will be used.
Click to expand...


I'd definitely agree with that, but the reason I was referring to is big trucks "only" have 400 or 500 horsepower, which as you know, is about the same as our "light" duty trucks.

In order to keep 80k lbs moving from 0 mph to 70+ mph they need the mathematical advantage 10+ speeds offers.

Yes, they have 1500 lb/ft of torque or so, but torque moves the load initially -- Horsepower is what allows the load to keep moving at speed.
 
gimmie11s said:
Uh huh. Do you know what that reason is?
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I do. The same reason a CVT would be the ideal transmission if you could make it’s ratio wide enough and build it able to handle high torque: keeping the engine in the ideal RPM range for a given speed/load/terrain.
 
If 8 and 10 speeds are supposedly to get better fuel MPG than, why are Ford and GMC getting worse than my 2020 3500 pulling 18K.
 
Xflight29 said:
If 8 and 10 speeds are supposedly to get better fuel MPG than, why are Ford and GMC getting worse than my 2020 3500 pulling 18K.
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Hard to compare just the transmission since the trucks have different engines, axles, and literally everything else. The only way you could really compare would blue the same truck with two different transmissions.
 
jsalbre said:
Hard to compare just the transmission since the trucks have different engines, axles, and literally everything else. The only way you could really compare would blue the same truck with two different transmissions.
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so comparing a transport to a pickup is fine when it fits your narrative but comparing a pickup to an equal pickup is completely different….
 
H3LZSN1P3R said:
so comparing a transport to a pickup is fine when it fits your narrative but comparing a pickup to an equal pickup is completely different….
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I wasn’t comparing a transport to a pickup, I was commenting on the reason for more gears.

If having more gears in a transmission (to a point) couldn’t improve the vehicle then you wouldn’t find a near unanimous agreement that the 6.4 with the new 8 speed is way better than the 6.4 with the old 6 speed. You’d also be driving a truck with a 3 speed transmission.
 
jsalbre said:
I wasn’t comparing a transport to a pickup, I was commenting on the reason for more gears.

If having more gears in a transmission (to a point) couldn’t improve the vehicle then you wouldn’t find a near unanimous agreement that the 6.4 with the new 8 speed is way better than the 6.4 with the old 6 speed. You’d also be driving a truck with a 3 speed transmission.
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Cant compare gas to diesel.. i had no issues with my 5.7 and six speed personally
 
Xflight29 said:
If 8 and 10 speeds are supposedly to get better fuel MPG than, why are Ford and GMC getting worse than my 2020 3500 pulling 18K.
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Some of that can be linked to both of them having 2 more cylinders and possibly even running at a higher RPM, more friction and pumping losses in both cases.
 
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