Gear ratio for 37s? Front locker only?

[tom.mary.glad]

So, I'm going to regear for 37s. 3.6L, auto, Sport.

I don't wheel much yet, but who knows when last kiddo goes off to college...

First, what gear ratio do you recommend? 4.88 or 5.13? I'm in TX = flat. I don't drive aggressively. I don't tow and don't plan to.

Second, is a front locker only a good idea? I figure since the rear has limited slip or BLD or whatever Jeep calls it, maybe I can save some money and only add front??

Thanks!

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[Josh00333]

4.88 would be my recommendation, if your flat land and not towing. I would probably go 5.13 if I was doing 37's but I'm out west in the mountains.

Locker, they the installer is literally there when installing gears. Now would be the time to do it.

I just did gears in mine and added an e-locker while they were there.

 

[JT1]

Gear is more related to what your average speed on the autobahns down there is.. if you are running 80-85 for hours at a time, vs parking in the slow lane at 70-75..

I have a 6spd and 5.13s on 37s and 80 is a comfortable cruising speed and right on the edge of the second stage of the oil pump kicking in. With the auto, you are about 200 rpm below me at the same speed. 4.88s will drop you another 100ish rpm at any given road speed when you are in 8th gear.

You 100% don't NEED a locker, but if you play in the mud a bunch, you'll eventually want one.

 

[Jrgunn5150]

I've only ever regretted not running more gear, never less.

Mine will get 5.13's when it's regeared.

 

[bleda2002]

So, I'm going to regear for 37s. 3.6L, auto, Sport.

I don't wheel much yet, but who knows when last kiddo goes off to college...

First, what gear ratio do you recommend? 4.88 or 5.13? I'm in TX = flat. I don't drive aggressively. I don't tow and don't plan to.

Second, is a front locker only a good idea? I figure since the rear has limited slip or BLD or whatever Jeep calls it, maybe I can save some money and only add front??

Thanks!

Do you have a limited slip in the rear, or just the BLD. BLD is just an open diff where the electronics squeeze the brake on one side in an attempt to send torque to the other, it works ok(better than most but its still an open diff). Jeep also offers an actual LSD in the rear, it works well. If you have an actual LSD in the rear i think just putting a locker in the front makes sense. If you just have an open diff, then put the locker in the rear and leave the front if you dont want 2 lockers.

Ratio, is completely up to you. I was happy with 4.10s and light 37's in florida when i didnt tow. I went 5.13's and am very happy with them when i went to beadlocks and 39's and doubly so for towing. The shop in town that does literally hundreds of JL's/JT's a year recommended 5.13 over 4.88 and so 3 of us all went 5.13's and not a single one of us wishes we went to 4.88. As always ymmv but it seems few and far between to see complaints from people who are unhappy with 5.13s in the auto given the double over drive of 7 and 8.

 

[Billyj7175]

I went with 4:88's with 37's and wish now I'd gone 5:13. I'm in Oklahoma, but frequent NM, CO & Utah. It's fine now on 37" RidgeGrapplers, which on the truck measure 35-3/4". If I ever run a taller tire, and I probably will at some point, I'm gonna wish I'd gone 5:13's.

 

[Panthers65]

I've only ever regretted not running more gear, never less.

Mine will get 5.13's when it's regeared.

Agreed. At that point there is no balancing MPGs, Above 70 your Jeep is going to get crap gas mileage, doesn't matter what you do. You are driving a truck with the aerodynamics of a brick on wheels.

Might as well gear deep and enjoy the extra power.

And the front locker with rear l/s is a popular setup. Obviously way better than leaving the front open, and very close to locked front and rear.

 

[Jefe1018]

Torqmasters just came out with a lunchbox for the front. I've had good times with set-ups like this on the front with an LSD in the rear.

https://torqmasters.com/product/torq-locker-tl-21032-for-jeep-gladiator-wrangler-front-m210-axle/

 

[BFgoodrich10]

4.88 would be my recommendation, if your flat land and not towing. I would probably go 5.13 if I was doing 37's but I'm out west in the mountains.

Locker, they the installer is literally there when installing gears. Now would be the time to do it.

I just did gears in mine and added an e-locker while they were there.

How much did that all run you? The regear and adding the locker?

 

[tom.mary.glad]

Do you have a limited slip in the rear, or just the BLD. BLD is just an open diff where the electronics squeeze the brake on one side in an attempt to send torque to the other, it works ok(better than most but its still an open diff). Jeep also offers an actual LSD in the rear, it works well. If you have an actual LSD in the rear i think just putting a locker in the front makes sense. If you just have an open diff, then put the locker in the rear and leave the front if you dont want 2 lockers.

Ratio, is completely up to you. I was happy with 4.10s and light 37's in florida when i didnt tow. I went 5.13's and am very happy with them when i went to beadlocks and 39's and doubly so for towing. The shop in town that does literally hundreds of JL's/JT's a year recommended 5.13 over 4.88 and so 3 of us all went 5.13's and not a single one of us wishes we went to 4.88. As always ymmv but it seems few and far between to see complaints from people who are unhappy with 5.13s in the auto given the double over drive of 7 and 8.

My build sheet states Trak-Lok anti-spin diff. So, I think its better than the BLD, right?

 

[Sikjeep2]

I would 100% go with 4:88. I originally went 5:13s with 37s and regretted it. I recently upsized to 40s and think is better. Way to much RPM with the 37s and going into 8th gear too soon.

 

[Wheelin98TJ]

I would 100% go with 4:88. I originally went 5:13s with 37s and regretted it. I recently upsized to 40s and think is better. Way to much RPM with the 37s and going into 8th gear too soon.

I'm surprised you thought it was way too much RPM.

5.13 with 37s is about 2,300 RPM at 70 MPH. Seems perfect to me.

 

[JT1]

I'm surprised you thought it was way too much RPM.

5.13 with 37s is about 2,300 RPM at 70 MPH. Seems perfect to me.

Never driven in Michigan, but if you've never driven in Texas, some of the regular highways are 80mph, and running 80 you get stuck behind all the semis. When I drive through there, I set the cruise between 85-90 just to keep up with regular traffic, and you'll still get run over by a 1 ton dually hauling a cattle or horse trailer.

At 85 with 5.13s and 37s you are up around 2800 rpm and close to the second stage of the oil pump.

 

[Bonanza]

I'm on 37s, and regeared to 4.88s. It's OK. It was slow stock, it's slow now, and it would be slow with 5.13s. I easily could've done lockers as I did my regear myself, but decided against it. I have the LSD in the rear, and with the traction control, I have never left a trail wishing I had lockers.

Which is ironic bc on my 2017 JKUR I used lockers all the time. The 2013 2 door before it? Never needed lockers then. Each vehicle has been on the same extreme rock trails in SoCal. I can't explain it but that's what it is.

 

[bleda2002]

My build sheet states Trak-Lok anti-spin diff. So, I think its better than the BLD, right?

Yes, you have a real limited slip so personally I'd just go front locker and leave the rear as a limited slip

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