Gears
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Gears
I have a 17 250 SD XLT 4x4 Crew Long bed. Unfortunately it only has an open diff and 3.31's. I tow a 38' toy hauler/travel trailer and I have 37" MT's so I am planning to do a gear change to either 4.10's or 4.30's. I figure while I am at it I should spend the extra cash and install a LSD or locker in the rear. My wife and I love road trips and we go to the mountians and desert. We won't be doing any crazy off roading. Obvously this isn't the right truck for that being that it's a super heavy, long bed and it's my daily driver. Just some mild to medium trails and snowy mountians. I just don't ever want to get stuck. Last year in the snow I never got stuck with 4wd on but I couldn't pull out of a slushy parking lot in 2wd.
Should I go for a rear torsion LSD or spring for rear ARB air locker? Should I spend the extra cash for an ARB front locker? Obviously there is a big price difference between no locker and 2 air lockers. I do already have a compressor and 150psi air tank for my airbags. But the more I have to spend the longer I'll have to wait to do it.
Should I go for a rear torsion LSD or spring for rear ARB air locker? Should I spend the extra cash for an ARB front locker? Obviously there is a big price difference between no locker and 2 air lockers. I do already have a compressor and 150psi air tank for my airbags. But the more I have to spend the longer I'll have to wait to do it.
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From: Norco
I don’t know what OEM tire size you were running by my ‘17 F250 Lariat CCSB has 275/70/18 an approximate 33” tire...so I’ll use 33” as the tire size.
A 37” tire changed your 3:31s to a 2:ninty7 effective gear ratio. In order to get back to a stock effective ratio of a 3:31 you would need to run 3:69 gears which are not offered but 3:73s are. If you are looking for a bit more “grunt” you could go lower gears like a 4:10 or 4:30.
Going a lower gear would raise the rpms you see while driving on the fwy but may be more comfortable in slower stop and go traffic/city driving.
If I was going to go to a 37” tire I would opt for the 3:73 to get back close to stock and the 6.7 does not lack for power down low.
Now on to the locker(s)....My truck came stock with a rear lockable differential, Eaton Elocker I think. I have only used it and 4WD (4lo) backing a trailer uphill in the dirt when the rear tires started to slip a bit. If your diffs are open, as you describe, I would add a rear locker when you regear. No use in paying for labor a 2nd time if you regear first. Also, I guess you could also throw a front locker at it too. Your choice between an ARB or electronic locker. With an air source, your compressor, a ARB may end up being a little less than a E Locker.
If pulling the trailer down slippery or snow covered roads at anything above almost a crawl, I would opt for a LSD in the rear, it would be more driver friendly. I would just use the locker(s) as insurance if stuck. Also running open/open, in just plain 4x4 (4hi) would be just fine since driving locked at speeds with both axles locked takes some getting used to, especially pulling a trailer.
HTH,
Mike
A 37” tire changed your 3:31s to a 2:ninty7 effective gear ratio. In order to get back to a stock effective ratio of a 3:31 you would need to run 3:69 gears which are not offered but 3:73s are. If you are looking for a bit more “grunt” you could go lower gears like a 4:10 or 4:30.
Going a lower gear would raise the rpms you see while driving on the fwy but may be more comfortable in slower stop and go traffic/city driving.
If I was going to go to a 37” tire I would opt for the 3:73 to get back close to stock and the 6.7 does not lack for power down low.
Now on to the locker(s)....My truck came stock with a rear lockable differential, Eaton Elocker I think. I have only used it and 4WD (4lo) backing a trailer uphill in the dirt when the rear tires started to slip a bit. If your diffs are open, as you describe, I would add a rear locker when you regear. No use in paying for labor a 2nd time if you regear first. Also, I guess you could also throw a front locker at it too. Your choice between an ARB or electronic locker. With an air source, your compressor, a ARB may end up being a little less than a E Locker.
If pulling the trailer down slippery or snow covered roads at anything above almost a crawl, I would opt for a LSD in the rear, it would be more driver friendly. I would just use the locker(s) as insurance if stuck. Also running open/open, in just plain 4x4 (4hi) would be just fine since driving locked at speeds with both axles locked takes some getting used to, especially pulling a trailer.
HTH,
Mike
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I don’t know what OEM tire size you were running by my ‘17 F250 Lariat CCSB has 275/70/18 an approximate 33” tire...so I’ll use 33” as the tire size.
A 37” tire changed your 3:31s to a 2:ninty7 effective gear ratio. In order to get back to a stock effective ratio of a 3:31 you would need to run 3:69 gears which are not offered but 3:73s are. If you are looking for a bit more “grunt” you could go lower gears like a 4:10 or 4:30.
Going a lower gear would raise the rpms you see while driving on the fwy but may be more comfortable in slower stop and go traffic/city driving.
If I was going to go to a 37” tire I would opt for the 3:73 to get back close to stock and the 6.7 does not lack for power down low.
Now on to the locker(s)....My truck came stock with a rear lockable differential, Eaton Elocker I think. I have only used it and 4WD (4lo) backing a trailer uphill in the dirt when the rear tires started to slip a bit. If your diffs are open, as you describe, I would add a rear locker when you regear. No use in paying for labor a 2nd time if you regear first. Also, I guess you could also throw a front locker at it too. Your choice between an ARB or electronic locker. With an air source, your compressor, a ARB may end up being a little less than a E Locker.
If pulling the trailer down slippery or snow covered roads at anything above almost a crawl, I would opt for a LSD in the rear, it would be more driver friendly. I would just use the locker(s) as insurance if stuck. Also running open/open, in just plain 4x4 (4hi) would be just fine since driving locked at speeds with both axles locked takes some getting used to, especially pulling a trailer.
HTH,
Mike
A 37” tire changed your 3:31s to a 2:ninty7 effective gear ratio. In order to get back to a stock effective ratio of a 3:31 you would need to run 3:69 gears which are not offered but 3:73s are. If you are looking for a bit more “grunt” you could go lower gears like a 4:10 or 4:30.
Going a lower gear would raise the rpms you see while driving on the fwy but may be more comfortable in slower stop and go traffic/city driving.
If I was going to go to a 37” tire I would opt for the 3:73 to get back close to stock and the 6.7 does not lack for power down low.
Now on to the locker(s)....My truck came stock with a rear lockable differential, Eaton Elocker I think. I have only used it and 4WD (4lo) backing a trailer uphill in the dirt when the rear tires started to slip a bit. If your diffs are open, as you describe, I would add a rear locker when you regear. No use in paying for labor a 2nd time if you regear first. Also, I guess you could also throw a front locker at it too. Your choice between an ARB or electronic locker. With an air source, your compressor, a ARB may end up being a little less than a E Locker.
If pulling the trailer down slippery or snow covered roads at anything above almost a crawl, I would opt for a LSD in the rear, it would be more driver friendly. I would just use the locker(s) as insurance if stuck. Also running open/open, in just plain 4x4 (4hi) would be just fine since driving locked at speeds with both axles locked takes some getting used to, especially pulling a trailer.
HTH,
Mike
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