4spd auto regear w/33's

FanAholic · 03-16-2008, 03:25 PM

What gears are you running with 33's for those of you who regeared and have the 4spd auto?

I was thinking about regearing and I have 33's but want to go to 35's eventually. Would 4.88's be to high for 33's?

**Jerry Bransford** · 03-16-2008, 04:07 PM

Go 4.88 for your 33" tires which will be ideal for that particular transmission that has a very deep overdrive gear ratio. Most with 35" tires report not even 4.88 is low enough for that transmission, they wish they could have gone with 5.13 but that is only possible with the Rubicon that has a Dana 44 up front.

By the way, in the world of gear ratios, a higher numerical number means a lower ratio. So 4.88 is actually a lower ratio than 4.56 is.

Sahara01 · 03-16-2008, 04:08 PM

I did 4.10's and 33's, a little sluggish in overdrive. 4.56 would be ideal. I have custom D60's under the jeep now and 5.13's for the 35's...

**Jerry Bransford** · 03-16-2008, 04:18 PM

Quote:

Originally Posted by Sahara01

I did 4.10's and 33's, a little sluggish in overdrive. 4.56 would be ideal. I have custom D60's under the jeep now and 5.13's for the 35's...

So you never drove 4.56 or 4.88 with 33" tires but you know 4.56 would be ideal and 4.88 wouldn't be? Certainly 4.88 isn't even low enough for 35" tires, just one step larger, but you went with 5.13 for those.

I'll stand by my 4.88 recommendation for 33" tires with the 4-speed automatic.

Sahara01 · 03-16-2008, 04:23 PM

Quote:

Originally Posted by Jerry Bransford

So you never drove 4.56 or 4.88 with 33" tires but you know 4.56 would be ideal and 4.88 wouldn't be? Certainly 4.88 isn't even low enough for 35" tires, just one step larger, but you went with 5.13 for those.

I'll stand by my 4.88 recommendation for 33" tires with the 4-speed automatic.

Yes I've driven a jeep with 4.56 and 33's. I didn't say 4.88 wouldn't be ok. I can tell you with the 35's and 5.13's I feel I could have gone to 5.38's...

Personal experiance on my jeep says 4.10's are definately NOT deep enough. 4.56 would have worked well on MY jeep.

ratster · 03-16-2008, 05:39 PM

4.88's are great on the trail but if it's mostly hwy driving I would do 4.56.
I lost about 1 1/2 to 2 miles per gallon when I went to 4.88's and I have the the same set up as you.But with that being said if you are gonna move up to 35's I would go with 4.88's.

04TJ Dogg · 03-16-2008, 07:27 PM

I've got a question regarding this topic. I have 33's with the aut with o/d amd run stock 3.73's and ya know that is not cutting it. Today I took a 1 hour trip to a cousins house for a b-day party. The drive varied speed from
50-80 mph. I drove there and back in drive and did not use o/d. It worked a whole lot better but at 80 I was turning about 3000-3200 rpms which I dont think is hurting anything. Anyways, I was jsut wondering if someone would give some input on the truth if that is hurting anything and what that gear ratio may actually be at. What rpms would I be running at 80 with 4.56's and 4.88's?

Thanks

Ron R · 03-16-2008, 11:35 PM

I have 4.56 in my 99 auto and 33's
Not bad, like 2900 rpm at 60 and enuff pep down low for some fun.
Not sure but I think mine is only a 3 speed auto?

**Jerry Bransford** · 03-16-2008, 11:37 PM

Quote:

Originally Posted by Ron R

I have 4.56 in my 99 auto and 33's
Not bad, like 2900 rpm at 60 and enuff pep down low for some fun.
Not sure but I think mine is only a 3 speed auto?

Like mine, yours is a 3-speed auto. The 4-speed auto came along in 2003.

04TJ Dogg · 03-17-2008, 07:00 PM

Well, if you're running 2900 rpms then I guess the 3000-3200 that I run shouldnt hurt anything, right?

Thanks

Xlr8n · 03-17-2008, 07:45 PM

fwiw- I have the factory 4.11's with 33's and the the 4 speed auto. While I had no issues with 32's, with the 33's I find I drive with the OD switched off most of the time except for long, flat interstate drives. At 55-60mphs I run at about 2800rpms with the OD off and about 1900-2000 rpms with it on. At lower speeds the gearing works out fine and shift points seem to be spot on. Not sure if the 1-3 gear ratios are the same as the older 3spd auto or not.

**robncar** · 03-17-2008, 10:16 PM

Do yourself a favor and listen to Jerry on this one. 4.88's with 33's and the 4-speed auto is the right combination.

I'm one of the guys Jerry's speaking about that has 4.88's with 35's and the 4-speed auto and wishes I could have gone with 5.13's but for the limit of the D30. I drive with the O/D off on the street.

As far as gearing nomenclature, one can speak of gearing in a couple of ways:

A 4.88 gear is said to be "lower" than a 4.56 but we know it's "numerically higher"; counterintuitive. So, when you said a gear is "too high" it could have been said "numerically too high" or just "too low".

I think I'm confused now...

That1guy · 03-18-2008, 01:39 AM

So what is the trans ratios for the 4spd? Not to high jack.

Roko · 03-18-2008, 02:13 AM

42RLE is: (On the JK at least, I don't think they would have changed the ratios between the TJ and JK?)

Gear Ratios 1st 2.84
Gear Ratios 2nd 1.57
Gear Ratios 3rd 1.0
Gear Ratios 4th 0.69
Gear Ratios Reverse 2.21

I too am looking to regear, I'm thinking 4.56 myself since I do long highway drives to get to any wheeling trails let alone other summer spots of interest. Right now 3.73 is killing me on gas mileage since it can't make up it's mind if it wants to stay in overdrive or not at highway speeds...

04TJ Dogg · 03-18-2008, 07:07 AM

Roko, i'm in the same situation you're in. I pretty much do the same kind of driving you do. I cant afford to regear right now (I have 3.73's also) so I turn the o/d of for now, at least that way its not lugging and trying to pour gas in the cylinders.