3:55 or 4:10
I wander what better to have on the truck rear axle 3:55 or 4:10 to pull a 15000 lb FW.What the mile difference driving solo?
Forum Discussion
add that is my thinking for now on my GMT400 7.4L Suburban with 4.1's
By installing a gear splitter function my 4 speed 4L80E will then
have 8 forward gears...AKA close ratio like the current gen of higher
number of gears.
Double OD too and noodling whether 0.5 or 0.75 on the Gear Vendors. OEM
4L80E is 0.75, IIRC, to provide a @ the drive shaft ratio of approx 0.56
in 2nd OD
Change both diff's to something like 4.54 ratio or even higher numerically
and the why of the decision whether 4.54's or 5.x's...but then the
pinion might be too small and have to change the OEM carrier for the reach...
Above applies to any vehicle and the available ratios will be specific to that
OEM and aftermarket offerings...
A cam to bring my OEM 7.4L's 410 ft/lbs at ~1,400 RPM up to +500 ft/lbs
but decision whether to bump the red line above the OEM set 4.8K RPMs
as I drive TVs to torque and my cars to HP...ever since the divorce,
no one demanding luxury & +30 footer stuff...toy hauler in the 28'
range will be fine for me and whomever
So that rat big block looking likely with a red line around 6K RPMs...
By installing a gear splitter function my 4 speed 4L80E will then
have 8 forward gears...AKA close ratio like the current gen of higher
number of gears.
Double OD too and noodling whether 0.5 or 0.75 on the Gear Vendors. OEM
4L80E is 0.75, IIRC, to provide a @ the drive shaft ratio of approx 0.56
in 2nd OD
Change both diff's to something like 4.54 ratio or even higher numerically
and the why of the decision whether 4.54's or 5.x's...but then the
pinion might be too small and have to change the OEM carrier for the reach...
Above applies to any vehicle and the available ratios will be specific to that
OEM and aftermarket offerings...
A cam to bring my OEM 7.4L's 410 ft/lbs at ~1,400 RPM up to +500 ft/lbs
but decision whether to bump the red line above the OEM set 4.8K RPMs
as I drive TVs to torque and my cars to HP...ever since the divorce,
no one demanding luxury & +30 footer stuff...toy hauler in the 28'
range will be fine for me and whomever
So that rat big block looking likely with a red line around 6K RPMs...
rjstractor wrote:Chuck_thehammer wrote:
that over/under drives the transmission. been available for many years..
I am talking about a 2 speed rear end... like a 3:73 and a 4:30.
they are NOT the same thing.
But the net effect is the same. That's why OTR trucks have transmissions with 9 to 18 speeds and typically have single speed rear axles. Modern six speed transmissions have made split rear ends unnecessary, especially with the abundance of power available.
