3.31 gears at 40,000 lbs gross.
Just to give a bit of a feel for how different gear ratios would behave while towing I locked out 10 then 10th and 9th then added them back again while travelling on a straight stretch of road w...
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4x4ord wrote:Grit dog wrote:RoyJ wrote:
Let's be fair to Ford and look at what Ram uses (I'm a big Mopar fan just to be clear):
3.75:1 Aisin 1st speed ratio, 4.10 axle ratio, 37,100 lbs tow rating. Works out to be 15.375 total ratio, or "2413 lbs per total gear ratio"
Ford: 4.615:1 1st gear, 3.55 axle ratio, 35,000 lbs towing. 16.383 total ratio, or 2136 lbs per gear ratio
So starting out in 1st gear, the 3.55 Ford has a 12% gearing advantage over an Aisin Ram running 4.10.
Never heard "lbs per gear ratio" unit of measure, but I'm tracking and your assumption is solid.
What you're confused about is the argument was never, is the trans (OD clutches, whatever) being overstressed. But rather higher final ratios put "more" stress on the trans, (OD clutches, driveline, whatever) and the answer is still resoundingly yes.
Oh, and I'm a Dodge guy too and they're again (sorry, still...) s ucking hind teat in the transmission department!
When a 4.30 vs a 3.31 are towing down the highway in 10th gear you’re right .... the 3.31 is putting little torque through the overdrive clutches and the 4.30 truck is putting even less torque through the OD clutches. Come to a hill and the 4.30 puts nearly peak engine torque through the OD clutches and the 3.31 equipped truck puts no torque through the OD clutches. Also if the same driver accelerates towing a trailer with a 3.31 equipped truck followed by a 4.30 equipped truck and the torque were measured on the driveline in each gear it is very likely that the torque measured would be close to identical. Torque on the axle would be higher with the 4.30 equipped truck. The thing is the 4.30 would jump up a gear and the 3.31 would now be putting higher torque to the axle until it also makes the shift.
Edit: (to bring a little more clarity) By the time the 3.31 truck is up to 65 mph in 7th or 8th gear the 4.30 truck is doing 65 mph and is in 10th. So, the driver of the 3.31 truck backs off on the accelerator and the transmission will make 2 or 3 more shifts under low torque.
You just stated exactly why lower gears are better than higher gears, even when towing marginally heavy.
Sheesh, this thread is longer winded than trying to tow a trailer with 3.30 gearing!
