Changing from 3.73 to 4.10 gears
Hello all, After towing our new Reflection 320MKS from Eastern Iowa to Estes Park Colorado and back, I need more power for the hills. I have a 2015 F-250 with the 6.2 Liter engine. I have 3.73 years...
Forum Discussion
Maybe this will help the OP and their question...
Yes, it will help and seems like most are in the weeds as to how much it will help, or not at all...
Hope this 60,000 foot view will help the OP decide
Any automotive transmission with more than one gear will have the lowest (highest numeric) ratio (ratio of the engine turns multiplied by that ratio...to get more rev's output from the tranny)
As you move up in gears from 1st to 2nd to 3rd...etc, etc, etc...to the old trannies with a 1:1 ratio (no multiplication) to today's with OD to even double OD (with a ratio of 0.75, 0.70, 0.65, etc that REDUCES the tranny output to less than one rpm going in...to less than one rpm going out)
Everyone knows that if you start the TV out in a higher gear, say 4th, it will buck and most likely kill the engine...or it will buck, shudder until there is enough engine RPMs to get into a bit more HP (HP = torque x RPM / 5252, so if the torque is constant and you provide more RPMs, there is more HP)
Simple as that and the why that all ICE transmissions have a high numeric 1st gear ratio and as it shifts to higher gears...it goes to lower number ratios
Now for the diff at the end of this rotational food chain...it is fixed (some big trucks have 2 speed diff's)...the differential, which is a single speed transmission
So if your transmission has lots more gears than older transmissions...it has the 'spread' of gear ratios to make up for that diff...but you have notice that the OEM's towing charts allow heavier trailers with higher numeric diff ratios
That is because of the torque multiplication of gear ratios. So going to higher numeric...it will have the drive shaft turn more times vs each (single) diff output shaft (axles).
Back to that image where the input shaft (smaller dia, pinion) gear drives the output shaft (larger dia, ring gear). Depending on their diameters, the input/output rev's will be determined (ratio of the gear set)
This is no different than the old lever arm lengths on both sides of a fulcrum....just round instead of a straight 2x4
So, say the input shaft (pinon gear) has 100 ft/lbs of torque...the output shaft (ring gear) will have more torque via the ratio
Meaning that if the diff ratio is 3.73, the 100 ft/lbs input/pinion will provide 374 ft/lbs of torque to the axles. A 4.1 ratio will provide 410 ft/lbs of torque to the axles. A 4.6 ratio will provide 460 ft/lbs to the axles....and so on
That then provides more HP via the formula HP = torque x RPM / 5252. So providing more RPMs to the axles (tires are connected to them), there is more HP delivered to the pavement
Of course there are other variables, but they would apply to any gear ratio and am only discussing the variables. That is where some comments are out in the weeds...IMHO...
Bottom line: higher numeric will increase the engine RPMs delivered to the diff input/pinion for every tire rotation. That will develop more HP...how much is dependent on your TV/engine/etc/etc attributes
Only you can decide how much you want or need. Trial and error will cost you, so folks with experiences can help with their stories...but...bottom line decision is yours, the OP...
Am noodling for my 1996 big block Suburban, which I ordered with 4.1's, a 5.1 or 5.88 (or whichever I can find) and stuff a GearVendors with a 0.5 OD behind the tranny and before the drive shaft. That will provide me with a double OD and 0.5 ratio between the 4L80E gears....that will give me an 8 speed automatic tranny and very large torque multiplication to the axle/wheels
oakmandan wrote:
Hello all,
After towing our new Reflection 320MKS from Eastern Iowa to Estes Park Colorado and back, I need more power for the hills. I have a 2015 F-250 with the 6.2 Liter engine. I have 3.73 years. Can they be swapped out for 4.10 gears, and will it help ?
Thanks
Yes, it will help and seems like most are in the weeds as to how much it will help, or not at all...
Hope this 60,000 foot view will help the OP decide
Any automotive transmission with more than one gear will have the lowest (highest numeric) ratio (ratio of the engine turns multiplied by that ratio...to get more rev's output from the tranny)
As you move up in gears from 1st to 2nd to 3rd...etc, etc, etc...to the old trannies with a 1:1 ratio (no multiplication) to today's with OD to even double OD (with a ratio of 0.75, 0.70, 0.65, etc that REDUCES the tranny output to less than one rpm going in...to less than one rpm going out)
Everyone knows that if you start the TV out in a higher gear, say 4th, it will buck and most likely kill the engine...or it will buck, shudder until there is enough engine RPMs to get into a bit more HP (HP = torque x RPM / 5252, so if the torque is constant and you provide more RPMs, there is more HP)
Simple as that and the why that all ICE transmissions have a high numeric 1st gear ratio and as it shifts to higher gears...it goes to lower number ratios
Now for the diff at the end of this rotational food chain...it is fixed (some big trucks have 2 speed diff's)...the differential, which is a single speed transmission
So if your transmission has lots more gears than older transmissions...it has the 'spread' of gear ratios to make up for that diff...but you have notice that the OEM's towing charts allow heavier trailers with higher numeric diff ratios
That is because of the torque multiplication of gear ratios. So going to higher numeric...it will have the drive shaft turn more times vs each (single) diff output shaft (axles).
Back to that image where the input shaft (smaller dia, pinion) gear drives the output shaft (larger dia, ring gear). Depending on their diameters, the input/output rev's will be determined (ratio of the gear set)
This is no different than the old lever arm lengths on both sides of a fulcrum....just round instead of a straight 2x4
So, say the input shaft (pinon gear) has 100 ft/lbs of torque...the output shaft (ring gear) will have more torque via the ratio
Meaning that if the diff ratio is 3.73, the 100 ft/lbs input/pinion will provide 374 ft/lbs of torque to the axles. A 4.1 ratio will provide 410 ft/lbs of torque to the axles. A 4.6 ratio will provide 460 ft/lbs to the axles....and so on
That then provides more HP via the formula HP = torque x RPM / 5252. So providing more RPMs to the axles (tires are connected to them), there is more HP delivered to the pavement
Of course there are other variables, but they would apply to any gear ratio and am only discussing the variables. That is where some comments are out in the weeds...IMHO...
Bottom line: higher numeric will increase the engine RPMs delivered to the diff input/pinion for every tire rotation. That will develop more HP...how much is dependent on your TV/engine/etc/etc attributes
Only you can decide how much you want or need. Trial and error will cost you, so folks with experiences can help with their stories...but...bottom line decision is yours, the OP...
Am noodling for my 1996 big block Suburban, which I ordered with 4.1's, a 5.1 or 5.88 (or whichever I can find) and stuff a GearVendors with a 0.5 OD behind the tranny and before the drive shaft. That will provide me with a double OD and 0.5 ratio between the 4L80E gears....that will give me an 8 speed automatic tranny and very large torque multiplication to the axle/wheels
