Question regarding gear swaps - Yukon 4.88 gears?

[JBrown]

I have quite a bit of gear experience currently running 35’s and 3.73’s on my old pickup... has not problem cruising the freeways and spinning the wheels at any time. It’s not a complicated. It all depends if you daily driving hwy or not. I don’t like spinning 3000 rpm at 70mph. It’s not worth it.

In a kinda nicer way to put it the transmission gearing is important as well. As well as engine power and where the torque curve actually is. With a Pentastar engine that really doesn't have it in the low end and a transmission with very wide gear spacing it makes a hell of a lot of sense to get aggressive with gearing to me. Especially if you have a sport that only has a 2.72 transfer case and don't plan on forking out for a rubi take out or an atlas. If you were to go one gear set deeper than you need at the moment you'd end up with a short 1st instead of a useless 6th

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[Krondor]

I'm still in break in period, but I'm already glad I got the 4.88's on my 2 door manual with 35's.

It feels right. :dunno:

Enjoy the build, whichever way you go.

 

[CarbonSteel]

In a kinda nicer way to put it the transmission gearing is important as well. As well as engine power and where the torque curve actually is. With a Pentastar engine that really doesn't have it in the low end and a transmission with very wide gear spacing it makes a hell of a lot of sense to get aggressive with gearing to me. Especially if you have a sport that only has a 2.72 transfer case and don't plan on forking out for a rubi take out or an atlas. If you were to go one gear set deeper than you need at the moment you'd end up with a short 1st instead of a useless 6th

This all day! I can't wait to re-gear my Rubicon.

 

[Krondor]

This all day! I can't wait to re-gear my Rubicon.

 

[TxJeepers]

man yall dont know sluggish until you try driving rubi 33's with sport 3.45 gears and the 6 speed. Just installed rubi axles with 4.10 my god what a difference. ill be adding 35's in the next year or so when my tires wear out. but will not re-gear. I wouldnt recommend 4.88 with 35's and the 6 speed. with 37's and 4:88's rolling on flat in 6th gear at 2400 rpm your looking closer to 2700 @70 with 35's real world. 4.56 is the number for 35's IMO

https://www.jlwranglerforums.com/fo...3-tires-in-6th-gear-72mph.58253/#post-1257240

wouldn’t listen to guy just throwing numbers and hasn’t regeared.

@Bekser

I just put in 4.88's on my 2 door Jeep with 6 speed. I also have a 2.5" lift and 35's.

I'm still driving nicely with no off-roading until I change the gear oil. Trail Jeeps recommended 1000 miles and so that's what I'll do.

Still, I'm already well pleased at the difference. The gears finally "feel right." I have even held steady mph going up hill in 6th. Not a steep hill, but still one I've done many times before and 5th would start to lose speed. WTF??

No heavy acceleration yet, but it's like the Jeep got an extra 50hp and moves much more easily. Not going to do highway speeds until after the gear oil change, but I expect a bit higher rpm's. Not too concerned as it doesn't feel drastic.

HIGHLY recommended IMHO.

(Can't wait to hit the trail or drive up to Eisenhower Tunnel to really get a feel for the changes.)

Yes, listen to guy who has actually done it and provides actual experience

I don’t have a manual but absolutely love running 5.13s in my 19 Rubi 3.6/auto/37’s.

 

[CarbonSteel]

Happening in the next few weeks!

 

[Krondor]

Happening in the next few weeks!

Already a favorite upgrade.

Up there with the Bestop Sunrider for hardtop.

You will not be disappointed.

 

[track.n.trail]

I’d go straight to 5.13s with a manual trans.

 

[Krondor]

I’d go straight to 5.13s with a manual trans.

I'd agree with that for a four door or if you are going to 37's. I intend to stick with 35's and not as heavy as a four door.

It's enough for me.

 

[dangerous dave]

Hopefully folks are still reading this thread. I have a 2019 Rubi Unlimited with the 6-speed. I thought I would like it, but after actually researching the ratios of the transmission (yeah, I know I should have done that before buying it), I realize why I don't. The thing I hate most is the wide spread between 1st and 2nd on this trans. You can't start out in 2nd and I have to run it to 4k+ in first. And to those who said Rubi's should have 4.56 from the factory.... truer words have not been spoken.

The local 4x4 shop I talked to says even with the stock tires I should go with 5.13's, buy once and be ready for 35's and bigger.

What I would like to know is this: of the people here on this thread that have gone to 4.88 and 5.13, are you able to start out in 2nd? I ran the numbers and compared to a JK Sport with the 3.21 rear, the second gear of the JL with a 5.13 rear isn't that much higher than the JK first gear, and the final drive with the JL trans isn't much different than a JK Rubicon with 4.10's. Long story short, I would like to see if re-gearing to the 5.13 is going to make it so I just use 2-6 in normal everyday driving with 33's or 35's.

 

[Krondor]

Long story short, I would like to see if re-gearing to the 5.13 is going to make it so I just use 2-6 in normal everyday driving with 33's or 35's.

I went with 4.88’s and 315/70-17’s.

I like it much much better than stock. I can start in second on flat ground but habit has me nudge forward with first still and then spin second to get to third. My least favorite jump is that second to third. Why?

Anyway, you would be able to skip first with 5.13 especially with 33’s. I’m not worried about a couple hundred rpms more at highway speeds. Still very reasonable. Not much more with the 5.13’s but on 33’s I’d not want to be on long highway drives.

Good luck with your choice either way.

 

[dangerous dave]

Thanks, that's what I was looking for. Nice color BTW I got Punk'n since it's Oregon State orange lol

 

[Krondor]

Thanks, that's what I was looking for. Nice color BTW I got Punk'n since it's Oregon State orange lol

So after your question I made it a point to try the 2nd start more often.

With 4.88's I think the gearing is still too tall to do so comfortably. You may have better luck with 5.13's.

I myself am loving the current setup as I do spend a majority of my time on the road.

Now that break in has been completed, I've loved the extra grunt off the line and she moves quite well. I'll be testing on the trails this weekend. Looking forward to seeing how 4 low has changed.

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