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4.88 or 4.56?

Just go with the 4.88's. Unless your awfully liberal with the throttle you shouldn't ever have a problem. Stock rpm's mean nothing when you go from 28" tires to 33" or bigger then add lift to clear them. I don't have any personal experience with 4.88's yet, but there is a set on the bench waiting to be put in my dad's rig.

Here's another example. My buddy with the toy runs 5.71's, 38's to 44's, dual transfer cases. Final bottom low is a little of 200:1. Granted this is behind a 4 cyl but that is a bunch of gear reduction. The pinion on those gears is not much larger than a quarter and the 4.88's for a 30 look to be a least 20-30% larger. It's so small that his gear vendor (long time, but I think it was Richmond) at the time refused to sell them to him because there was no way they would last more than a week. About three years ago the rear end finally let go and that was 10 years after the original setup. The fronts have never been touched. That was ten years of daily driving and weekly wheeling.

He still get's the blunt of my blame for me buying 4.10's when I had 32's. He should have beat me with a stick to get his point accross. I was too busy thinking RPM's, stock, etc. :looser: That was long before NAXJA and 4.88's existed. I'm still thinking 5.38's and 35's are the ticket.

Lincoln
 
I have 35s and 4:56s (auto) in my daily driver. Everyday I drive it I kick myself in the a$$ for not going to 4:88s. Just do the 88s so you dont spend the money twice.
 
Beezil said:
"not enough tooth mesh".....

have you seen these two gearsets on a meshed on a table and compared the amount of surface area in the mesh?

its indistinguishable......
Click to expand...


Spoken with the voice of experience.....(I too run 4.88's.... Cry 'bu!!sh!t on the pinion issues)


Phil Weeks said:
BTT for this one. Who has personally broken 4.88s? Who is running, or has run, 4.88s in an HP D30?
Click to expand...

Running them with 35" MT/R's and 180K on the odometer. They are fine as far as an actual gearset (I think mine are Sierra brand if I remember correctly). The D30 is kind of a seperate issue (I'm on my second housing due to the first being bent)......... I searched as many boards as I possibly could to find any pinion issues when I bought my gears. I didn't find anything substantial enough NOT to buy the 4.88 over the 4.56. I like the 4.88 as my engine is TIRED. Let's me cruise at 70 or so even at 5400 ft. without a lot of RPM......(I'm still getting 16-17 mpg on the open road)
 
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.....Dr. DooBeezil? .....to back up Beezil?

OK, I'll be the 3rd. 'Mo out of the closet.........Beezil, you're so sexy!...There,...I said it...

anyone else? ;)
 
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Ok, I guess it's time to build a 44 rear and go for 4.88s. Oh darn.:D
Replacing the D30 with something better is not going to happen now, or I probably would go lower. Oh yeah, I've got 35" MT/Rs and I'm right around 165K on my odometer.
 
The 4.88's should work out ok of you have a O.D. trans..My trans has a 1:1 high gear...the motor turns about 3,500 at 70mph...
 
I had a manual HO YJ on 33's with 456's LOVED it....now i have a auto XJ on 35's with 456s and wouldn't change a thing...(except to a V8).... never had a problem...i'd say with an auto stick to the lower 456s...just to save wear on the engine and trany....488s is alot of gear with no overdrive....

Otherside of the coin....my buddy runs a TJ with 488s and 35s (manual) and say its great.....but i think he wishes he would have gone with 456s....because he was forced to move upto 35s just to lower the RPM...and get OK-esh mileage.....
 
Mrburns said:
I had a manual HO YJ on 33's with 456's LOVED it....now i have a auto XJ on 35's with 456s and wouldn't change a thing...(except to a V8).... never had a problem...i'd say with an auto stick to the lower 456s...just to save wear on the engine and trany....488s is alot of gear with no overdrive....

Otherside of the coin....my buddy runs a TJ with 488s and 35s (manual) and say its great.....but i think he wishes he would have gone with 456s....because he was forced to move upto 35s just to lower the RPM...and get OK-esh mileage.....
Click to expand...

AW4s have an overdrive that's the same or slightly taller than an AX15, AX5, or BA10.


Jes
 
I have seen that randy's is carrying 5:38's for the D 30. Has anyone heard anything about these? I had planned on regearing a long time ago but it didn't work out. This rig sees very little freeway time, and may even be retired to a trail rig soon. I have the aw-4 so I have the o/d and I plan to stay with at least 35's. Any thoughts? TIA Neil
 
wow....thats some low gears....

Let me know how they workout....like maybe a 2wk and 6month review...??
 
Neil said:
I have seen that randy's is carrying 5:38's for the D 30. Has anyone heard anything about these? I had planned on regearing a long time ago but it didn't work out. This rig sees very little freeway time, and may even be retired to a trail rig soon. I have the aw-4 so I have the o/d and I plan to stay with at least 35's. Any thoughts? TIA Neil
Click to expand...

Beware, that is for a standard cut D30 and will not fit a HP D30.

I ran 4.56 and 35s for over 2 years as a DD and wished i had lower gears. On the other side i broke 2 sets of gears while wheeling with my 38.5 SXs. Now i have 5.86 with 37s and they're great.
 
Randy's specifies standard and reverse cut for the 5:38's
 
Phil - There's a guy in Vacaville that has two 44's. One from a MJ and one from a XJ. Think he was asking $450. Each had LS and about 150K miles. search the forsale forum.
 
basalt51 said:
Phil - There's a guy in Vacaville that has two 44's. One from a MJ and one from a XJ. Think he was asking $450. Each had LS and about 150K miles. search the forsale forum.
Click to expand...
I saw it the other day, I think I was just hoping for something a little bit cheaper. I don't think the LS really matters for me, don't I need a low gear carrier? I think when I do it I'll go full case locker, I think Detroit. MJ axle would be nice though, no cutting off mounts and perches, just weld on the new. Jeez, I think to much. I need to just do.

Sounds like 4.88s in a D30 aren't really a problem after all? Aside from it being a D30.
 
I'm gunna go with 4.56s with 29inch tires. I hated losing just the tiny amount of torque when I went to 235s and running 3.55s.
 
I'm moving up to 33" MT/Rs so I'm following this discussion pretty closely. What is the general consensus for 33s? I doubt that I'll ever move up to 35s as I'm in a wheelchair and there's a limit somewhere to what I can climb into.

On a related note try this link.

http://www.ring-pinion.com/calculators/calculatorsind.html

The calculator doesn't work out quite correctly to real world, but at least you can compare what you've got to what you'll have when you're through.
 
XJWheelie said:
I'm moving up to 33" MT/Rs so I'm following this discussion pretty closely. What is the general consensus for 33s? I doubt that I'll ever move up to 35s as I'm in a wheelchair and there's a limit somewhere to what I can climb into.

On a related note try this link.

http://www.ring-pinion.com/calculators/calculatorsind.html

The calculator doesn't work out quite correctly to real world, but at least you can compare what you've got to what you'll have when you're through.
Click to expand...

I run 4.56's w. 33's w. the AW4 and think it works great, but I'd also seriously consider 4.88's. Depends on what you want, more bottom end/trail or top end/hwy. If you do alot of road trips and especially if your t-case is geared lower than stock, go 4.56, if low end is more important go 4.88, some might say go even lower...here...check this out.... http://www.quadratec.com/cgi-bin/sg...h_corner/gear_ratio.html&UID=2003080806361105 Hope it helps!!
 
Well, when talking gearing, all anyone ever talks about is tire size and gear ratio. Well, you also need to take into account tire type and engine output. My non-ho 4.0 with 32" Swampers and 4.10's is a dog. Mostly because Swampers are heavy and drag horribly. Can't wait to go up in tire size, as I will loose 4th gear again.
If it was me, I wouldn't even think about 4.56's for 35's. But, I would be running Bias Swampers. With the extra height, weight, and drag, I would go 4.88.
This is merely my opinion, so take it or leave it.
 
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