3.73 or 4.10 gears?
- Thread starter 68lemans462
- Start date
I have the 6 speed with 4.56 gears and it runs at 75-80 mph down the flat interstate here at 2900 rpm. I've been to Moab and drove through SD and around the black hills without any issues. I have 35" tires, 3.5" lift, front and rear e-lockers, and a tummy tuck.
It works for me as a daily driver and is capable enough for what I do offroad.
It works for me as a daily driver and is capable enough for what I do offroad.
Summary in advance: 4.56
33s. 3" Teraflex lift.
Upgraded gears a few years ago: 4.56 from 3.73. Yukons + EATON 912A569 Trutrac limited slip diff in the rear.
The fun returned — a substantial performance boost for the dinky 2.4L.
I'm one gear higher throughout the range — highway: used to be at 2400+- RPMs in 5th @, say, 55-60mph — I'm now comfortably cruising in 6th, 2400+- RPMs @ 65+-mph.
33s. 3" Teraflex lift.
Upgraded gears a few years ago: 4.56 from 3.73. Yukons + EATON 912A569 Trutrac limited slip diff in the rear.
The fun returned — a substantial performance boost for the dinky 2.4L.
I'm one gear higher throughout the range — highway: used to be at 2400+- RPMs in 5th @, say, 55-60mph — I'm now comfortably cruising in 6th, 2400+- RPMs @ 65+-mph.
Your 6 speed is a different transmission with different ratios than the 5 speed being discussed.
FWIW, if you're keeping the Dana 30 up front (street vehicle so it's probably fine), look into automatic 2.4 TJ parts vehicles. There's likely hundreds on marketplace due to TJ rust. TJ's equipped with a 2.4 and an auto trans actually had 4.56's from the factory. That solves the front, and you only have to regear the rear.
Getting ready to regear a GM 10 bolt from 3.08 to 3.73 myself.
I know, I know…
Not a bolt in though. Different u joint at least, and I’m pretty curious at 230,000 miles how long I can drag the factory ones out.
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"Necessary" is really up to you to decide. I have a 98 Sahara 4.0L/AX-15 with 31's and 3.73 gears. I live in New England where there are a decent amount of hills, and for me this is fine, but I'm not at high elevation or towing/wheeling frequently. I wouldn't want larger tires than the 31s I have without regearing. I think 4.10s with 31s would be the sweet spot, but then again you are doubling the cost regearing both axles vs just the rear.
With aircraft it’s common to “turbonormalize.” That is where a turbo is used, but not for drastic horsepower improvements, rather to only maintain sea level density altitude when you are flying at higher altitude. This way, you are maintaining sea level performance without engine strain beyond what it was designed for.
I would expect some enterprising Rocky Mountain tinkerer to come up with a way to accomplish this with sal\vage yard parts. With most cars having been factory equipped with turbochargers in the last 10 or more years, it should be easy and cheap to accomplish this. Since you’re not looking for high boost, the turbo lag would be minimal.
In the case of the OP, since he’s currently geared 3.07, turbonormalization and say 3.73’s could make a very sweet rig for John Denver country,.
An enterprising person could find a common wrecking yard turbo and wastegate, build a few pipes/flanges/etc., and sell as a kit to normalize the 4.0 and sell them all over the Western US.
My $0.02
I would expect some enterprising Rocky Mountain tinkerer to come up with a way to accomplish this with sal\vage yard parts. With most cars having been factory equipped with turbochargers in the last 10 or more years, it should be easy and cheap to accomplish this. Since you’re not looking for high boost, the turbo lag would be minimal.
In the case of the OP, since he’s currently geared 3.07, turbonormalization and say 3.73’s could make a very sweet rig for John Denver country,.
An enterprising person could find a common wrecking yard turbo and wastegate, build a few pipes/flanges/etc., and sell as a kit to normalize the 4.0 and sell them all over the Western US.
My $0.02
What LSD are you using? A Torsen type such as the Eaton Truetrac will be more effective and long lasting. The clutch type last as little as 30,000 miles before they wear out at which time they become an open diff.
Some lunchbox lockers in the front can cause steering problems. I was told that the Spartan works better in the front. This is the combination now in my truck that only sees pavement or mud. Haven’t had the need to make it through mud yet so I am not ready to offer a thorough report.
I think your ratio choice is good. It’s far enough from a 3.07 to make real difference.
Some lunchbox lockers in the front can cause steering problems. I was told that the Spartan works better in the front. This is the combination now in my truck that only sees pavement or mud. Haven’t had the need to make it through mud yet so I am not ready to offer a thorough report.
I think your ratio choice is good. It’s far enough from a 3.07 to make real difference.
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