towing
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Senior User
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i can see that but really 2k vs 7k thats quite a difference. also why are the lower gears rated less for towing with the 4.9 i have 3.08s and when if downshifts it puts it right at the factory peak torque rpm where as 4.10 or possibly even 3.55 would rev passed the peak torque rpm. or are the factory numbers inacurrate
Post Fiend
Joined: Mar 2002
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From: Bonita Springs FL
also why are the lower gears rated less for towing with the 4.9
Work = force * distance
It's the same reason that a vehicle will accelerate much faster in lower gears than in higher ones. A lower (numerically higher) gear ratio gives you more usable torque at the wheels.
More torque = more towing capacity.
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Doesn't matter as much because your gear ratio is relative to the torque output at the wheels. Once you get into the higher gears, your ratio transmit less torque.
FTE Legend
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From: Ottawa, Ontario
As the gear ratio gets higher(numerically lower) the pinion gear gets progressively smaller compared to the ring gear and smaller pieces can't handle as much TQ as bigger pieces so the load rating of those parts will be lower.
Regardless of the engine it's attached to and the operating rpm at any given speed, lower axle gear ratios(3.55s or 4.10s) put more torque to the ground(higher mechanical advantage) so towing performance and unloaded acceleration improves.
Regardless of the engine it's attached to and the operating rpm at any given speed, lower axle gear ratios(3.55s or 4.10s) put more torque to the ground(higher mechanical advantage) so towing performance and unloaded acceleration improves.
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Posting Guru
Joined: Jul 2008
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This. Autos also multiply torque because of the torque converter which helps improve towing for the otherwise same truck.
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Post Fiend
Joined: Mar 2002
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From: Bonita Springs FL
No. Gears multiply torque. If the motor makes 200 lb-ft of torque, a set of 3.08 gears will deliver 616 lb-ft to the wheels, assuming a 1:1 transmission ratio and no parasitic driveline losses. A set of 4.10 gears will deliver 820 lb-ft of torque.
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