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Re Gear 99 sahara 5 speed and 33's

3K views 36 replies 11 participants last post by  xxdabroxx 
#1 ·
Rear has a bearing going out so I am going to go ahead and re gear at this point and add an OX air locker in the rear D44. D30 front as well. Got a quote for 1300 before the locker. Question is what gearing do people recommend for this setup on 33x12.50x15's with the 5 speed and thinking about going to 35's later down the road?

I have been thinking 4.56's for years but talked to another gear guy and he said might go 4.88's.....

Already running 33's on what I think are 3.73 gear ratio....
 
#4 ·
I run 4.56/33 on a NV3550/4.0. It's barely getting by at 2250/65mph. I wish I had gone deeper, but that's for the next iteration.

If you have the D44 go deep if you want more umph sacrificing top-end speed. 4.0L's torque peak is 3000rpm, keeping rpms near makes work effortless. Revolution now makes a 5.13 for a D30 (pn D30S-513TJ or D30S-513TJ). Refer to attached charts.

4.88/35 for stock (3.73) feel.
5.13/35 for more power.

btw: punch your numbers in here http://calc.teammfactory.com/

35's on 5.13 / 4.88 / 4.56







33's on 5.13 / 4.88 / 4.56





 
#6 ·
I run 4.56/33 on a NV3550/4.0. It's barely getting by at 2250/65mph.
Something's not right with that low of an rpm, that combination should be generating closer to 2520 RPMs with the NV3550 at 65 mph. That 2250 rpm you described is more like what the 42RLE 4-speed automatic would generate with its .69 overdrive ratio.
 
#9 ·
I guess y'all are right maybe 4.88's are the way to go....

Might be setting these up on my own after doing a lot of reading last night and today. I have most of the tools and can rent the ones I don't have for free a dial indicator is 20 bucks a HF also...

I am more than likely going with an OX air locker too!

My first question with installation is since this project normally requires a carrier swap for the D44 will I still be able to use the same carrier bearings to make setup bearings?
 
#10 ·
That 9,000' elevation of Crested Butte was my sole reason for believing going one step deeper than the normal recommendation of 4.56 would be warranted.

Your existing bearings would make good setup bearings, use a brake cylinder hone to slightly enlarge the inner race.

Why Ox? Which method of actuation?
 
#11 ·
That 9,000' elevation of Crested Butte was my sole reason for believing going one step deeper than the normal recommendation of 4.56 would be warranted.

Your existing bearings would make good setup bearings, use a brake cylinder hone to slightly enlarge the inner race.

Why Ox? Which method of actuation?
Thanks Jerry!

I have been looking into OX for a while and like that the new air setup looks bombproof compared to ARB, Eaton etc. Just seems like a better product. I don't like the idea of o rings and lines getting messed up on the ARB and others seem about the same price but not the same quality build.
 
#16 ·
I think I found about the same deal on an ARB and OBA as for the OX so hope Jerry returns to sell me on the ARB.

I am also probably setting this up on my own after all the research I have done lately. I have a press and most of the tools required. Anyone got a link to that DIY regear guide?

Will I need new bearings to use as set up bearings or can i use the old ones as I am going from 3.54 or 3.73 to 4.88's not sure if the carrier break will have anything to do with the bearing size I am betting it will require a new set to make into setups though....
 
#17 ·
Im a happy air actuated OX locker customer. I run mine off a 20oz co2 tank. The likelihood of damaging the elbow that enters the stout differential cover is low to me. The push lock 1/4 hoses and fittings are really slick and they're commonly used on commercial trucks. The air switch I used is a Velvac switch with a peterbilt part number on it.
 

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#19 ·
I do some serious crawling out in CO during the warmer summer months although I have never needed to be locked before and have done some gnarlz I think it won't hurt anything and have had troubles in mud from time to time that would assist IMHO. It shouldn't hurt anything and I will keep the OX in mind. Did you install it or pay to have it done? I have that push fitting in my mind as the weak link is it all brass? What about a replacement fitting? Never hit my diff cover up there either though.....
 
#22 ·
Its DONE OX on the way with OBA! Sweet! Now I gotta figure out if I am gonna pull the diffs off or do it on the rig.....

Where to folks buy gears and install kits? Heard Timken Bearings and races are the way to go! I need a new speedo gear for 33's too never bothered to do that quite yet....oh well...

Got a 1.25 JKS BL and JKS MML 1" in the mail today too going to do winch, tubes, rails, and rear bumper to finish this thing up. Its been a work in progress I still need a front track bar and new tie rod though so they will get to eventually....

99 Sahara
d30 d44 5speed manual
OME 2.5 HD kit w shocks
OME steering Stabilizer
JKS Quick Sway Bar Disconnects
Durango Steering Box Upgrade
33 x 12.50 x 15 TRXUS M/T's
Pro Comp Flat Black 6 shooters
Rusty's Pre Runner Front Bumper
Cree LED 12 inch light bar
 
#28 ·
Wow, and the D44 in the rear. It seems like you've got a great foundation there. Other than the OX, which wouldn't have been my choice--especially if you're going air actuated(!!) and looking past ARB.

You ever decide for sure which ratio to go for? 4.56 would work well, but while I wouldn't normally say it, 4.88 may not be a bad idea due to the occasional high altitude and low top speed (I think you said you'd never get past 65 or so). And you probably wouldn't need to regear again for 35's. The altitude never seemed to be be any problem for my 2006 4.0L, even at 12k+ feet in some of the passes in CO, I believe Stony Pass in particular. But maybe for others it might be?
 
#30 ·
Been doing it on 3.73 stock gears with heavy Trxus MT 33x12.50x15's on her so 4.56 oughta do it for me but as far as OX goes it seems strong especially with the diff cover and the drive away actuator for $25 but the quick fittings are not likely to hit anything. I used to live out of the back of my stock 97 sport 4.0 on pearl pass every night for 8 weeks in the summer had to wake up before dawn to crawl to town for work so it will get it done. Probably don't need it really but I have had instances were locking would have felt a bit less scary considering....only problems I have seen on the OX is the manual cable shifter which I am not dealing with here....
 
#29 ·
Deacon said:
Wow, and the D44 in the rear. It seems like you've got a great foundation there. Other than the OX, which wouldn't have been my choice--especially if you're going air actuated(!!) and looking past ARB. You ever decide for sure which ratio to go for? 4.56 would work well, but while I wouldn't normally say it, 4.88 may not be a bad idea due to the occasional high altitude and low top speed (I think you said you'd never get past 65 or so). And you probably wouldn't need to regear again for 35's. The altitude never seemed to be be any problem for my 2006 4.0L, even at 12k+ feet in some of the passes in CO, I believe Stony Pass in particular. But maybe for others it might be?
So what's your experience with air actuated OX that makes it not a solid choice?
 
#32 ·
LOL... I guess you don't read too good.

I've never owned OX. I've only been around those who have. When they work, great. When they don't, they don't. And it sucks to be held up on the trail because someone said screw the best, I'm going to be different. It's not a question of "strength" but of known, proven reliability, serviceability, customer service, and having been tortured by some of the harshest buggies and rock racers out there. Go see what percentage of KOH runners (much less Winner's) are running it, no matter where it claims to be made.

Here's my unbroken Eaton E-Locker equipped rig having conquered Billings Canyon outside Grand Junction, stacked up on a friend's rig with another broken MURICA OX in it that made life decidedly difficult.

 
#35 ·
On my '06 I noticed no difference at 12,500 feet elevation than at sea level. I don't like sitting in the 3200+ RPM range for cruising, would rather that be more like 2800 to 2900. So I would go with 4.56 because an extra couple hundred RPM aren't necessary and are not my personal preference. Now, if I were doing a lot of towing, of a jet ski or expedition trailer or something like that, I would probably approach it differently.
 
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