Regearing for towing (sometimes) and driving in Colorado: 4.88 vs 5.13 can you share experience?

[darkhorse13]

Sorry for the delayed response! Still waiting for my lift to arrive but I did get my regear done. Overall very pleased with the 5.13 gears. It has surprised me in that on a flat it is holding 8th gear at 45MPG, lol! I haven't taken it on any long trips yet but the throttle response is much better now and from what I can tell much less hunting for the right torque/gear combo. Going to take a longer trip to Durango in 2 weeks. Won't be able to tow with it until we get out camper next spring. Overall tho, I think 5.13 gears is a no-brainer for this truck anywhere in the US but particularly here in CO.

I'll report more in a few weeks when I get some more mileage under my belt...

How are them 5.13's still feeling in the mountains?

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[FR33DOM]

How are them 5.13's still feeling in the mountains?

I'm very pleased with them and super glad I didn't go with 4.88. FAR less shifting/hunting than before (even compared to 4.10 on 33" tires). Just took a trip to Durango and back and even though I think we had a hefty head wind both ways, we still easily saw a 1-2 mpg uptick from before (4.10 on 37").

THAT SAID, I do somewhat wonder if I should have gone even deeper to 5.38 as I do plan on pulling a trailer a lot next summer. I know it will be tow just fine on 5:13s but even as a daily driver I suspect 5.38 (just 5% more) would have few negative consequences as long as you are not constantly driving over 80mph lol. Maybe this is a minority opinion BUT I have yet to hear anyone say they regretted gearing too deep.

Bottom line: I have no hesitation in recommending 5.13 gears on a JT with 37" tires anywhere in the country: mountains or low elevation flat land.

 

[WK2JT]

Okay, so still in GA at the moment and just finished the 500 mile break-in. I went with 5.13. Definitely feels much better, runs through the gears quickly and will hit 8th around 43 MPH. 75 MPH spins about 2,450 RPM and feels strong. Definitely glad I went this deep for the mountains as I will rarely run it at 80 MPH. 5.38 might have been a little too deep for my liking, but it’s definitely doable I feel. However, I believe you lose another pinion tooth at that point. Hope this helps someone as I went back and forth about what ratio to get. Honestly, there isn’t a lot of difference, so anything would be better than stock.

 

[FR33DOM]

Okay, so still in GA at the moment and just finished the 500 mile break-in. I went with 5.13. Definitely feels much better, runs through the gears quickly and will hit 8th around 43 MPH. 75 MPH spins about 2,450 RPM and feels strong. Definitely glad I went this deep for the mountains as I will rarely run it at 80 MPH. 5.38 might have been a little too deep for my liking, but it’s definitely doable I feel. However, I believe you lose another pinion tooth at that point. Hope this helps someone as I went back and forth about what ratio to get. Honestly, there isn’t a lot of difference, so anything would be better than stock.

I share the same feelings @WK2JT -- Man, I'm starting to wish I'd gone to 5.38s lol!

I'll just add the more I research the more I think there is no valid fear in strength limitations of 5.13s or 5.38 especially on 37's. Found this video today to be helpful. According to this you do keep all 8 teeth on 5.38s as on 4.88s and 5.13:

 

[StingyJT]

I share the same feelings @WK2JT -- Man, I'm starting to wish I'd gone to 5.38s lol!

I'll just add the more I research the more I think there is no valid fear in strength limitations of 5.13s or 5.38 especially on 37's. Found this video today to be helpful. According to this you do keep all 8 teeth on 5.38s as on 4.88s and 5.13:

You just described my exact predicament of 4.88 and 5.13s with potential set of 35s for long trips/towing. I'm in Utah, so you're post is pushing me to 5.13s.

Any updates? Thanks!

 

[hjdca]

I have 1100 miles now with 5:13s with a manual JTR. I live in the mountains and have been driving up and down hills. It's like a different truck. Lots of torque now, really no lack of power now with 37s. Note: I have a light set of 37s - Goodyear MTRs with Method 703 bead grip.

 

[FR33DOM]

You just described my exact predicament of 4.88 and 5.13s with potential set of 35s for long trips/towing. I'm in Utah, so you're post is pushing me to 5.13s.

Any updates? Thanks!

Not really any updates and my feelings are the same as before. I am still very pleased that I chose 5.13 over 4.88 for daily driving and road trips. I still don’t yet have my trailer so haven’t towed any yet.

I will have to do some towing and / possibly borrow a set of 35” (to simulate 5.38 gears on 37”) to get any idea if 5.38 would have been better. I hope someone else gives them a try but my gut says 5.38 will run great on 37 too with little if any downside.

Bottom line: I still think 5.13 on 37’s is a no brainer choice for any JT auto and probably best fit for mileage and power. Jury is still out on towing.

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