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-   -   4:56 or 4:88 ??? (http://www.wranglerforum.com/f282/4-56-or-4-88-a-231001.html)

Telarian 03-28-2013 02:48 PM

4:56 or 4:88 ???
 
This has probably been asked 1000 times but here goes again. I have the money saved to regear.

Its an 03 Rubicon 4.0 3sp +Od Auto trans. (42RLE I think) Stock gears 4:11'S:

33" cooper STT's

For around town and normal driving it's fine as is. But in OD on the hwy and in thick mud or deeper snow it's a dog.

As I figured it 4:56's should put me a bit better than stock. And would still make low range somewhat useful. This is WI so there is no rock climbing just mud and snow. Low range is too slow most times as is with the rubicon transfer case.

I think 4:88's would make low range useless here and maybe a bit too much for highway driving.

Anyone out there with one of these setups let me know your opinion's!!!

Thanks

Jerry Bransford 03-28-2013 02:52 PM

For your 4-speed 42RLE automatic transmission, 4.88 is the right ratio for 33" tires. For other transmission types, 4.10 and 4.56 are often appropriate but not for the 42RLE.

povchrisw 03-28-2013 02:53 PM

with od 4.88 puts od close to stock power, i cant speak for 4 low

OhSixTJ 03-28-2013 03:24 PM

Quote:

Originally Posted by Jerry Bransford (Post 3564410)
For your 4-speed 42RLE automatic transmission, 4.88 is the right ratio for 33" tires. For other transmission types, 4.10 and 4.56 are often appropriate but not for the 42RLE.

I have 4.56 with a 4 speed auto :/

Rubicon1968 03-28-2013 03:26 PM

I did 456 wish I would have done 488

Telarian 03-28-2013 03:33 PM

Thanks for the quick responses!!

Any ideas where the RPM's at 65 MPH would be for the 4:88"s vs the 4:56's??

According to some ratio calculators to put it back to stock would be around 4:37's if there was such a thing. But even at stock OD is doggy.

I'm just a bit leary of 4:88's being overkill,, I do respect your opinions though.

Telarian 03-28-2013 03:36 PM

Quote:

Originally Posted by Rubicon1968 (Post 3564541)
I did 456 wish I would have done 488


Do you have the 42RLE Auto OD tranny???

Liftkit55 03-28-2013 04:04 PM

I have '97 TJ with a 4 cyl 5 spd with stock gears. In town is ok but the freeway kills me with any strong wind or hills. Should I go with 4.88 or 4.56. 80% my driving is freeway. Oh and I have 31x10.5x15

Jerry Bransford 03-28-2013 04:10 PM

Quote:

Originally Posted by Liftkit55 (Post 3564659)
I have '97 TJ with a 4 cyl 5 spd with stock gears. In town is ok but the freeway kills me with any strong wind or hills. Should I go with 4.88 or 4.56. 80% my driving is freeway. Oh and I have 31x10.5x15

I would keep what you have until you decide to go to 33" tires where 4.88 is appropriate. Yes your TJ with its 2.5L will be a little gutless in those conditions but it's just not worth the $1300-1500 to regear yet with only 31" tires. At least not in my personal opinion. :)

Jmaddox22472 03-28-2013 04:27 PM

4.88 for sure!

OhSixTJ 03-28-2013 05:06 PM

Does engine size matter in regards to 4.56 vs 4.88 on a 4 speed? I have the 4.0

Jerry Bransford 03-28-2013 05:25 PM

Quote:

Originally Posted by OhSixTJ (Post 3564925)
Does engine size matter in regards to 4.56 vs 4.88 on a 4 speed? I have the 4.0

Yes engine size matters but the 4.88 recommendation we made for 33" tires and the 4-speed automatic assumed a 4.0L engine.

Coasttrash 03-28-2013 05:40 PM

so for 36s 5.13s using a 42rle

Jerry Bransford 03-28-2013 05:44 PM

Quote:

Originally Posted by Coasttrash (Post 3565069)
so for 36s 5.13s using a 42rle

I'd go 5.38 for 36". I wish I had 5.13 or 5.38 gears just with my 35" tires. I bought my replacement Jeep used & it came with only 4.88 for its 35" tires & the engine lugs all the time. My finger gets wore out constantly turning the Overdrive off when it starts lugging.

Telarian 03-28-2013 07:43 PM

After doing more RPM & Ratio calculators I have come to the conclusion You guys are right. 4:88's are the way to go. For sure.

The step from 4:11 to 4:56 is just not as big as it sounds!!

Should never doubt the experts!!! :redface:

Thanks for the input!!

Fullback40 03-28-2013 09:16 PM

I have 33's with 4\56 gears I'm pretty sure 35's would be great with the same set up. Pulls hard through all the gears.

OhSixTJ 03-28-2013 09:29 PM

Quote:

Originally Posted by Fullback40 (Post 3565965)
I have 33's with 4\56 gears I'm pretty sure 35's would be great with the same set up. Pulls hard through all the gears.

That's what I was thinking as I was driving right now. It's actually a pretty quick jeep considering the tires it has to roll. And it can burn them at a light if I want it to.

CGipson 03-28-2013 10:17 PM

I have the same question what gears should I use? I have a 98 TJ 4.0 3speed auto with 33/12.50
tires and stock 3.07 gears for now.

strictly420 03-28-2013 10:39 PM

not to sure about 4.88's with a auto trans but on my last TJ I was using 4.88's with a 5 speed manual and felt it was over kill while running 33's, great on the trails but screamed on the highways.

UnlimitedLJ04 03-28-2013 10:47 PM

The general rule of thumb:

For 4.0L autos:
32RH (3-speed 97-02)
33s = 4.10s
35s = 4.56s
----
42RLE (4-speed 03-06)
33s = 4.88s
35s = 5.13s if you want to keep stock Rubi locker, 5.38s if you can.

For 4.0L manual =
5-speeds (AX15/NV3550)
33s = 4.56s
35s = 4.88s
----
6-speed (NSG370)
33s = 4.10s (4.56s will work for towing/mountains)
35s = 4.56s (4.88s for towing/mountains)

schnutzy 03-28-2013 10:48 PM

Quote:

Originally Posted by CGipson
I have the same question what gears should I use? I have a 98 TJ 4.0 3speed auto with 33/12.50
tires and stock 3.07 gears for now.

4.10 would be the way to go with the the speed auto and 33s

Quote:

Originally Posted by strictly420
not to sure about 4.88's with a auto trans but on my last TJ I was using 4.88's with a 5 speed manual and felt it was over kill while running 33's, great on the trails but screamed on the highways.

The 4 speed auto had a very tall overdrive gear, which is why it requires such low gears in the diffs

Telarian 05-04-2013 07:48 AM

Just thought I'd update.

03 Rubicon 42rle tranny and stock 4:11 gears ,, 33" tires

After the comments I received on here,,, and doing more research I decided the 4:88's where the way to go.

I wanted to get Nitro gears so I found JTs just differentials. Called them,, and talked at length with a salesman named Mike. They were out of 4:88's for the Rubicon at the time but they had 5:13's. He said, If I have heavy aftermarket bumpers, winch, and pull at all I would love the 5:13's. I do pull a boat and have the heavy stuff,,, so I agreed to the 5:13's (was a bit nervous about this choice).

To shorten this some. The 5:13's are great I love them. rpms at 65 mph ( GPS mph) are 2300 and no need to use the overdrive off button anymore. And I could go to 35's down the road if I want.

Anyone with the same 42rle tranny thinking to regear,, I would recommend at least the 4:88's or even go to the 5:13's. 4:56 is right out. The jump in gears sounds much bigger than it really is.

Thanks everyone for the advice above...

Border Dave 05-04-2013 08:04 PM

Quote:

Originally Posted by UnlimitedLJ04 (Post 3566348)
The general rule of thumb:

For 4.0L autos:
32RH (3-speed 97-02)
33s = 4.10s
35s = 4.56s
----
42RLE (4-speed 03-06)
33s = 4.88s
35s = 5.13s if you want to keep stock Rubi locker, 5.38s if you can.

For 4.0L manual =
5-speeds (AX15/NV3550)
33s = 4.56s
35s = 4.88s
----
6-speed (NSG370)
33s = 4.10s (4.56s will work for towing/mountains)
35s = 4.56s (4.88s for towing/mountains)

4.0 with AW4 (Cherokee transplant)
33s = 4.56s
35s = 4.88s

dezertdirt 05-04-2013 08:29 PM

I have an 05 rubicon, the 42rle, 33's and 4.88 gears. On the road its great, a little higher revs than stock for a given highway speed. Great around town. Off road, 4wd hi is great, 4 wheel low is really, really low. There are times I wish I could skip 1st altogether in 4lo because its so low. If I could make the choice knowing what I know now, would I do it again?...yep.

To answer an earlier question,I went from stock 245-16s (30") and 4.10 gears to 285-16s (33") and 4.88 gears and my rpms at 70mph went from 2200 stock to 2400 now

UnlimitedRubicon 05-05-2013 12:09 AM

Quote:

Originally Posted by Telarian (Post 3718090)
To shorten this some. The 5:13's are great I love them. rpms at 65 mph ( GPS mph) are 2300 and no need to use the overdrive off button anymore. And I could go to 35's down the road if I want.


Nice. :thumb: I'd rather have too much gear than not enough gear.

OhSixTJ 05-05-2013 01:05 AM

Quote:

Originally Posted by dezertdirt (Post 3719908)
There are times I wish I could skip 1st altogether in 4lo because its so low.

You can. Instead of puttiing it in "D", put it in "2". Simple.

Telarian 05-05-2013 04:36 PM

I agree with the 4 lo being really slow,,,It would be great for the rock climbers and that kind of work. But here in central WI I never use 4 Lo. We have the thick sticky clay mud and lots of snow so all I ever use is 4 Hi. A little speed and momentum is my friend!!


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