Re-gearing for 33" tires

[Chris.817]

Hi folks. This is a 2004 TJ, I6 5sp currently running 3.07 gears. I am trying to make the decision between 4.11 and 4.56 gears for 33" tires (more like 32.5" as they sit with 1000 miles or so on them). I really need to optimize more toward highway versus offroading. In the current situation, the wife thinks it's "broke" because she can't use 5th gear and will probably complain that it's too load if she's running around at 3200rpm at 75mph.

And... I need to drive 200 highway miles to go offroading.

Most of what I read here, and using the various calculators and tables suggest 4.56. Will I be disappointed at spending all the time and money to do 4.11? I will be doing the labor myself.

Thanks in advance.

 

[Feralkid]

if you're gonna regear do at least 4.88

 

[TripMcneely]

I run 4.11s with 33's and average around 15mpg. Couple mornings of 70+, couple mornings puttin around town most weeks. I have no complaints or feel the need to go higher but I'm fairly new to all of this.

 

[Jerry Bransford]

4.11 is slightly undergeared for 33's (which are all slightly smaller than 33"). I made the mistake of only regearing to 4.11 for my 33's against the advice of my more experienced Jeep buddies and the shop that installed them. Within 3-4 days after the regear to 4.11 I realized I had screwed up by not having gone to 4.56 which is the optimal ratio for the highway which of course works great offroad too.

And know too that just having slightly lower rpms like with 4.11 vs. the slightly higher rpms of 4.56 does not usually mean better mpg. In fact, on my current TJ which came geared with 4.88 for 35's with the 4-speed automatic which produces too low of a highway rpm, it was lugging on the highway and never got above 11 mpg. I regeared it to 5.38 which instantly gave better highway drivability plus my mpg went from 11 to 14.6.

Go for 4.56, you won't regret it.

 

[Jerry Bransford]

if you're gonna regear do at least 4.88

I would not regear to 4.88 for 33's with a 5-speed and 4.0 engine since he lives at a low altitude, Virginia. I'd only go 4.88 for 33's and 5-speed if I lived in the mountains like in Denver.

 

[Chris.817]

Thanks so much! 4.56 it is! I guess my next post will be "How is this paint pattern?" I do have all the tools, a lift, and plenty of time.

 

[jjvw]

4.88. I don't care where you live.

 

[Jerry Bransford]

Thanks so much! 4.56 it is! I guess my next post will be "How is this paint pattern?" I do have all the tools, a lift, and plenty of time.

Good for you but that job calls for perfection... no rushing it. An imperfect setup will mean toasted new gears in short order. And make darned sure the gear lube you break the gears in with is a conventional, NOT a synthetic. New aftermarket gears run hot during the break-in process and it was found that synthetic gear lubes don't cool the gears as well as a conventional gear lube does. Which is why gear manufacturers like Revolution Gear (the best) and Yukon recommend a conventional gear lube. Same with axle manufacturers like Currie and Dynatrac.

 

[Chris.817]

Thanks Jerry. I do have experienced help. Would you buy from Morris?

Also... I will need new carriers going from 3.07 to 4.56 correct. And at 180k miles, new spider gears would be a good idea I assume.

 

[BlueC]

Also... I will need new carriers going from 3.07 to 4.56 correct. And at 180k miles, new spider gears would be a good idea I assume.

Yes, you'll need a new carrier to make that change. At 180K, IMO you basically need to overhaul the axles since you will be in there. So new bearings, seals and spider gears if staying open. If you are considering a limited slip unit, now is the time to do that. Something like a TrueTrac probably won't cost much more than new standard carrier and spider gears.

For what it's worth, I'm running 33" with 4.10 gears (4.0, 5 speed) in an area with only a few more hills than what you have and I wish I was geared 4.56. The 4.10s are fine, but what I consider to be the high side. Getting into the mountains or pulling a small load and 5th gear isn't very useful for me.

 

[Tob]

Just to add myself as a data point, 4.10 gears with 33s and the NV-3550 is just past the line between “barely tolerable” and “this sucks”.

And I live at sea level, with zero elevation changes except for bridges and interstate embankments.

 

[TheBoogieman]

since he lives at a low altitude, Virginia. if I lived in the mountains like in Denver.

Don't be fooled by the low altitude here. There's plenty of mountains at Va Beach. They have contests to show them off.

 

[Jodh]

What about 33s with a 6 speed 4.0, still 4.56?

 

[jjvw]

What about 33s with a 6 speed 4.0, still 4.56?

It's more appropriate than with the 5 speed. But 4.88 wouldn't be out of the question, either.

 

[Jerry Bransford]

What about 33s with a 6 speed 4.0, still 4.56?

Yep 6th gear . 83 gearing isn't that much different from the .78 5th gear ratio on the 5-speed.

 

[Chris.817]

Don't be fooled by the low altitude here. There's plenty of mountains at Va Beach. They have contests to show them off.


View attachment 400506

Gotta love ECSC!

 

[Chris.817]

Thanks BlueC. Just placed an order through East Coast Gear Supply. I have used them in the past for Toyota work. Great folks. They suggested and supplied new, pre-honed bearings for setup. New wheel bearings and seals for the rear. They also suggested there was no reason to replace the front spider gears.

I went with Yukon.

 

[MutantNinjaTJ]

What about 33s with a 6 speed 4.0, still 4.56?

yes.