Question:
I'm looking for some imput on my gear change for my new 35" tires. I have a 2003 TJ with 4.0 and 5 speed trans. I don't care about fuel milage because I don't drive it to work.

Choices:
4.56
4.88

 

If you don't care about fuel milage or higher RPM's on the highway then go with 4.88's.

I think those 4.88 wood rock

since you have the 5sp is why I say the 4.88

i have 35's' and 4.56's and love em

I would use 4.56 w/auto & 4.88 w/5 speed.

4 88 all the way works awesome with the 5 to 1 t case

Anybody know the RPM difference between the 2 on the highway

I run 4.56s w/ 36"swampers and I can start out in 2nd gear with little bog. The gears have a nice wide range of operation, and cruising at 70mph isn't sending my tach much over the 2000 rpm range

quote:

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Originally posted by SprungTJ:
Anybody know the RPM difference between the 2 on the highway

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At 65 mph in 4th gear (1:1) w/ Manual - all numbers are approximate:

35 w/ 4.88's: 3045 rpm
35 w/ 4.56's: 2845

Stock TJ w/ 3.07's: ~2420

Stock TJ w/ 30" wheel & tire package & 3.73's: 2715

Rubicon (~31's & 4.10's): 2896

And of course keep in mind that you have an overdrive so in theory you should be fine with either choice. The 4.88's will work better off-road... but you should also keep in mind (depending on your driving style) that the pinion gear gets awfully small w/ 4.88's.. not that I have seen more broken 4.88's then 4.56's but it is just more data to collect.

Don't know much about 4.56s but I went from 3.07 to 4.88 and love em. As for fuel mileage who knows since my new speedo gear crapped out.

with the dana 30 i wouldn't go any lower than 4.56. if i had a 44 in the front then i would go with 4.88. i wouldn't trust myself with 4.88 and a dana 30 but that is just me.

I looked into the 4.88vs 4.56, and a local shop agrees with the pinion gear bein really small in a dana30 with 4.88's. Just go to keep the skinny pedal tame.

Well the 4.88 are going in next week. I look at it this way if I break it I will fix it once if it doesn't take out the Arb. If it takes out the Arb than I replace it with a Dana 44. I talked to wife and she's ok with that. This is the last thing I'm going to do to the Dana 30. An Atlas is next maybe this gear change will make me happy for some time.

good luck... be ready to shift like crazy, assuming its a stick.

even though it's an old thread ..... I'm happy with my 4.56's (4.0, 5spd, 35" MT/R's), but I wish I would've gone for the 4.88's

And the whole thing about 4.88's being that much smaller than the 4.56's and thus being more prone to failure is just an internet tale

I think I may be spending too much time deciding which lift/tires/rims to go with. After reading through a lot of boards, I'm now considering 35" rubber. I have a 2003 Rubicon, stock. DD and WW so I need to keep a reasonable ride on the road, and decent mileage. I did the math and it looks like if I changed to 4.56 gears, my RPM's would be the about same with the 35's as with the stock 31's. If I have alloy wheels, and 35" MT/R's, a 4.5" RE lift, and I'll cut to fit any more clearance I need. Can someone give me an idea how my ride would be on the road, and what the effect would be on my fuel mileage by going with the 35's instead of 33's? Anything else I should be considering? I don't want to dump all this money into my rig and regret not getting something different.

i have 35's and have had them for so long that i cant really remember how it drove before. keep em aired to about 30pounds and dont run to stiff of a shock and you'll be fine.. if you dont like em just remember that in 6 months they'll be worn down to a 33 regardless..

YOu wont need to cut to fit 35s with a 4.5 rubicon.

If it's a D35 rear, I'd go with 4.56's and reduce the gears in the tcase. That way you can retain some sort of r&p strength and get your gearing reduction.