Re-gear from 3.73 to 5.13

[Jeeper44mag]

Yeah right, somebody smoking weed.....My 392 Wrangler with 5.38 gearing won't run 11's so a stock 3.73 gear 3.6 V6 on 34's.......might run 18's.

1/8th mile? Damn sure isn't 1/4 mile. LOL

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[mtudb24]

Yeah right, somebody smoking weed.....My 392 Wrangler with 5.38 gearing won't run 11's so a stock 3.73 gear 3.6 V6 on 34's.......might run 18's.

Maybe he was talking about 11 parsecs like in the Millennium Falcon
Hell, my old 2007 awd trailblazer SS with a tune and other mods would barely hit low to mid 13's in the 1/4 mile

 

[Sweetums]

This. ^^^^ BFG "37's" are actually ~35.5"

I think Mickey Thompson is pretty close to the advertised size, but they are not cheap.

 

[slodsm]

5.13’s and the 3.6 go together perfectly. Smallest tire I’ve ran was a 37” Toyo open country, it’s heavy, spun about 2500 at 75 and got 16mpg. With 40’s I get 15.5 or so on the highway and 16+ in town. Best I had was 38” pats and it got 16.5 on the highway as they’re light as hell. I drive 600ish miles to work once a month so she gets a lot of interstate time

 

[Jrgunn5150]

No one ever regrets going lower, only higher.

I have 4.88's with stock 32's and it's barely adequate. But manages to not explode, kill my puppy, and transport us up and down the highway just fine.

 

[Wheelin98TJ]

No one ever regrets going lower, only higher.

I have 4.88's with stock 32's and it's barely adequate. But manages to not explode, kill my puppy, and transport us up and down the highway just fine.

Usually yes, but someone here will gladly argue this.

 

[slodsm]

Usually yes, but someone here will gladly argue this.

ALWAYS! 37’s and 3.73’s but it’s”ok because of the 8 speed, I barely notice”

 

[NC_Overland]

Usually yes, but someone here will gladly argue this.

I’ve had great results with 3.21s and 37s.

 

[guardrail]

new to the forum. new to the jeep community also. never owned a jeep until recently. purchased a 2025 gladiator in december bone stock from the dealer. went right to town with upgrades and did a 2.5 inch lift and paired it with 17inch black rhino arsenal wheels as well as 37 inch mickey thompson baja a/t tires. i had a reputable shop near me do all the work and i couldn’t be happier. they also did fox shocks with the lift and all new upgraded steering components.

i am currently lagging with the stock 3.73 gearing. the truck struggles to find 6/7/8th gears on the highway at mid speed. no power at all when trying to get around another vehicle. i absolutely have to drive the truck in manual mode to avoid the trans struggling to find what gear it should be in.

i ordered 5.13 gearing and i am awaiting the shops call to have it installed. i was borderline 4.88 gearing and i pulled the trigger on the 5.13 instead.

looking for any comment on someone who went from 3.73 to 5.13 and what you like/do not like about the gear change or if you regret not doing 4.88 instead.

purchase has been made so no going back at this point. i’m more or less looking for reassurance that i made the correct choice.

I’ve seen some videos on YouTube that indicate the 5.13 pinion in the stock axles are so small they’ve been known to break. I think Ozark Overland had this issue.

 

[Wheelin98TJ]

I’ve seen some videos on YouTube that indicate the 5.13 pinion in the stock axles are so small they’ve been known to break. I think Ozark Overland had this issue.

It's a somewhat common misconception that deeper gears have a weaker pinion, but it's not true.

 

[slodsm]

I’ve seen some videos on YouTube that indicate the 5.13 pinion in the stock axles are so small they’ve been known to break. I think Ozark Overland had this issue.

That’s the 5.38 and it’s an issue with bad wheel hop, it can happen to 4.10’s and 3.73’s as well. A poor install will just bite you faster with deeper gears due to higher ta multiplication and a smaller pinion which will really exacerbate the issue of excessive backlash.
.
The majority of guys with 37’s and bigger are running 5.13’s with no issues.

 

[Wheelin98TJ]

That’s the 5.38 and it’s an issue with bad wheel hop, it can happen to 4.10’s and 3.73’s as well. A poor install will just bite you faster with deeper gears due to higher ta multiplication and a smaller pinion which will really exacerbate the issue of excessive backlash.
.
The majority of guys with 37’s and bigger are running 5.13’s with no issues.

Dana says otherwise.

 

[ndesantis]

I’ve seen some videos on YouTube that indicate the 5.13 pinion in the stock axles are so small they’ve been known to break. I think Ozark Overland had this issue.

I think that video he referenced having 5.29 gears with the pinion issue. also possible he didn’t break them in properly or because he drove massive amounts right out of the gate they torched. who knows but I think after all the feedback and additional research I feel pretty confident in the 5.13 gears. My local shop had delayed shipping issues on the purchase so it set me back a few weeks on the install. Next week they go in and ai

 

[slodsm]

Dana says otherwise.

Ryan from engineering is assuming a proper .006-.010 backlash, proper pinion depth, and no abuse.

The people saying the pinion on the 5.38 can cause issues are expecting abuse.

Either way, if you aren’t on wet rock wheel hopping like hell as you try to climb something it doesn’t matter. From a metallurgical standpoint, there is zero difference in strength. From a usage standpoint, there is less room for error.

This is no different that a guy thinking a Dana 60 is bulletproof and then breaking it on 37’s with a motor making only 280 ftlbs of tq. A rated number it good for normal operations. Once you start binding/loading/wheel hopping etc, all bets are off.

 

[Jrgunn5150]

The wankers most concerned about that will never break a pinion in the REI parking lot trying to get up on the snowbank to park.

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