Explain Gearing to Me

[Moose843]

24 Sport S with 4:10 gears. I installed 35x11.5s, steel bumpers, a winch, a tool box, and tools. So my weight increase is 500-600lbs. When I use the formula for gearing, I come up with 4:62. Should I go 4:56 or 4:88? I will be 90% daily driving on roads and highways, 5% on the interstate, and 5% trail riding/light rocks type trails. I will also be pulling my boat (1500-2000lbs) once a week. Furthest boat landing being 30 miles from home. And I want to see 8th gear when I’m on the interstate at 80 mph. Help please, I’m a complete dummy in most automotive stuff.

Sponsored

 

[Wheelin98TJ]

4.88.

A little extra torque multiplication over stock will be appreciated for the weight you added.

 

[BennieD]

4.88. Having mine done next week. Not much difference between 4.10 and 4.56. Juice not worth the squeeze on that

 

[Her mojave]

I have a Mojave 23 i run 37 12.50 mud tire ...and i live in the mountains ...I went Dana 4.88 and im very light nothing added and to be honest my jeep still wants to drop to 6th gear when I have the cruse on. But I do see 8th way more than I did with the 410 ...I dont haul with mine so cant give any advice there but if im dropping to 6th with the windows down you will still run high rpms and lower gears when u haul...maybe u should look into like 513 if you are heavy and hauling

 

[Josh00333]

4.63 from Nitro.

https://www.extremeterrain.com/nitr...-ring-pinion-463-gear-ratio-gpjl-463-rub.html

What I went with.

 

[Panthers65]

You'll hardly notice the step between 4.10's and 4.56s. I'm a big fan of overgearing Jeeps, I'd almost always go up a ratio.

4.88's is my vote. Especially with you stating your Interstate is so low. I'm running 5.13's on mine on 37's and love it. I'm on the interstate regularly, and can still easily run 75-80 without problems.

 

[Advntrbound]

I'm going with 5.13s next month. 35s no other added accessories other than a tonneau cover. But I do live in the hills and pull a 3500lb camper, oh yeah, I only have 6 gears

 

[Blade1668]

I'm with BennyD on this, going from 4:10 to 4:56 isn't worth the money and time (I might question even 4:88). My passed experience is my XJ it started with 3:54/55 gears (27-29" tires)and I re-geared to 4:56 (33-35" tires) according to the gear swap calculator I should have done 4:10 the 4:56 turned out way better and increased my fuel economy actually along with on and off-road performance.
My 05 Wrangler Unlimited has 3:73 gears stock (tires 29-30" now running heavy old 33" MT) only way I'd re-gear to 4:10 is if I got a screaming deal on complete axles with lockers. Not worth the money and time otherwise, maybe 4:56 and would install lockers.
The down side of lower gearing is axle temperature though, so a shorter gear oil life too. My XJ you could wrap up a burrito in foil tie to pumpkin drive at highway speed and cook it if driving a few hours.

 

[Moose843]

So I’m a YouTube addict. Simply, I watch YouTube to death about a subject. So here goes:
1) 4:88 vs 5:13. Nothing has changed from original post
2) fuel mileage difference between 4:10 and either of above
3) at what point will I need an aftermarket diff cover to hold more oil
4) will I also need a bigger diff cover for the front
5) my shop quoted me yukon gears- pros vs cons
6) is there a better gear? Should I go with Dana to match the axles?

 

[Her mojave]

This man is a genius and the reason I stay broke watch this

 

[Zachanadandy]

I'm with BennyD on this, going from 4:10 to 4:56 isn't worth the money and time (I might question even 4:88). My passed experience is my XJ it started with 3:54/55 gears (27-29" tires)and I re-geared to 4:56 (33-35" tires) according to the gear swap calculator I should have done 4:10 the 4:56 turned out way better and increased my fuel economy actually along with on and off-road performance.
My 05 Wrangler Unlimited has 3:73 gears stock (tires 29-30" now running heavy old 33" MT) only way I'd re-gear to 4:10 is if I got a screaming deal on complete axles with lockers. Not worth the money and time otherwise, maybe 4:56 and would install lockers.
The down side of lower gearing is axle temperature though, so a shorter gear oil life too. My XJ you could wrap up a burrito in foil tie to pumpkin drive at highway speed and cook it if driving a few hours.

Comparing pretty much any experience with any other transmission, especially an auto, is pointless. The 1st gear in the 8 speed is so low for auto it's like a while other planet. The 42RE in the TJs had a 2.84-1 1st gear. That's about half way between 2nd and 3rd in the 8 speed. To match the 1st gear ratio of a TJ with 4.56s we would need 2.75 axle gears. Conversely for the TJ to match our 1st gear final drive ratio they would need 6.78-1 axle gears. That's why you'll find half the people on the JT and JL forums running 37s with no regear and they are perfectly happy. We don't need any more crawl ratio than the ridiculous 19.27-1 1st or the absurd 77-1 crawl ratio in low range regardless of tire size. The double overdrive on the other end let's you overhear by a large margin without much loss either so then we get the "you need 5.13s with 35s" crowd. The 8 aired has such a massive gearing range that in reality it almost doesn't matter. I definitely wouldn't spend $2-3k to go from 4.10s to 4.56s. Of course I wouldn't regear for 35s. My mojave has been on 37s since 1100 miles and still on stock gears. 30k miles later and there's nothing I'd need it to do that it doesn't. Hold 85mph on the freeway for hours at a time? No problem. Break the tires loose from a stop if I hammer it? Yep. Tow an 8400lb trailer 600 miles including up a grade that covers 3500' of gain in 18 miles while having no problem maintaining 65mph? Yep. I don't see anything to be gained by regearing. We went 5.38s and 38s on our JLUR and lost mpgs vs the 4.10s. It was in 8th at any speed over 40mph. On the freeway you'd be looking for another upshift that never came.

 

[Blade1668]

Comparing pretty much any experience with any other transmission, especially an auto, is pointless. The 1st gear in the 8 speed is so low for auto it's like a while other planet. The 42RE in the TJs had a 2.84-1 1st gear. That's about half way between 2nd and 3rd in the 8 speed. To match the 1st gear ratio of a TJ with 4.56s we would need 2.75 axle gears. Conversely for the TJ to match our 1st gear final drive ratio they would need 6.78-1 axle gears. That's why you'll find half the people on the JT and JL forums running 37s with no regear and they are perfectly happy. We don't need any more crawl ratio than the ridiculous 19.27-1 1st or the absurd 77-1 crawl ratio in low range regardless of tire size. The double overdrive on the other end let's you overhear by a large margin without much loss either so then we get the "you need 5.13s with 35s" crowd. The 8 aired has such a massive gearing range that in reality it almost doesn't matter. I definitely wouldn't spend $2-3k to go from 4.10s to 4.56s. Of course I wouldn't regear for 35s. My mojave has been on 37s since 1100 miles and still on stock gears. 30k miles later and there's nothing I'd need it to do that it doesn't. Hold 85mph on the freeway for hours at a time? No problem. Break the tires loose from a stop if I hammer it? Yep. Tow an 8400lb trailer 600 miles including up a grade that covers 3500' of gain in 18 miles while having no problem maintaining 65mph? Yep. I don't see anything to be gained by regearing. We went 5.38s and 38s on our JLUR and lost mpgs vs the 4.10s. It was in 8th at any speed over 40mph. On the freeway you'd be looking for another upshift that never came.

Well my "TJ" is a Unlimited with the 6 speed M.T. and basically same one that in JK's and JL's first gear isn't really used unless tire size changed or some road conditions. Some of the "re-gear" crowd wants to get back some of the mpgs and why some change gears. I definitely noticed the change towing and just driving going with larger tire (more rolling mass and pounds) size. Close to 10 mpg less along with higher temperatures in oil, transmission and coolant when towing. Next the transmission down shifts to 4th at times a lot and fishing for a gear. (might be part of some cam shafts and lifter failures for some???) Along with deciding 7th gear is it's favorite more often. (No I don't plan on changing gears in mine 4:10 already. )
But it really depends on the person and their use of the vehicle.
FYI I wouldn't recommend regearing from 4:10 to 4:56 in any case where I was buying gears, install kits time etc. Unless I got a smoking hot deal on complete axles ready to bolt in with lockers. Hmm, I think I typed that out before recently.

Sponsored