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Gears- Hp,Lp,reverse cut?? HELP!!

MG2000XJ

NAXJA Forum User
Ok so Im looking into regearing my axles and have no idea where to start... I think 4.56's is what I need with my 33's but not totally sure.I have a Lp dana 30 front axle and a 29 spline 8.25. I was looking for packages but didnt find anything. I found gears for the 29 spline and I found "reverse cut" gears for the dana 30. Is this what I need or no?
 
Yeah, that's right, but are you gonna install em yourself?

By your questions, I'd guess it may be over your head. Nothing personal, gears are tricky. I've done everything on my rig myself but balancing tires and setting up gears.

So if you're going to a shop for the work, they may prefer selling you the gears and install kit.

If you do want to buy em yourself, call Randy's. GREAT service...

Robert
 
Hey, I have a 2000 XJ also with the low pinion dana 30, I've got 32" tires and going to change to 4.56 gears. As far as I know the reverse cut gears are for the high pinion dana 30, not low. Yeah most websites I have visited also assume that the 2000 and 2001 have high pinion, which is why they offer the reverse cut gears. I think 2000 was the first year for the lp d30. I think they just took the front d30 off the Wranglers and stuck it under the XJ's.
 
Your low pinion D30 uses standard cut gears--not "reverse cut", which are for high pinion diffs.
 
Dynatrac said:
Perhaps the single most misunderstood axle term is reverse cut, often mistakenly referred to as reverse rotation. A reverse cut housing is not a standard cut housing turned upside down, it is a specially designed housing. The term "reverse cut" refers to the direction of the spiral cut in the ring gear, which is opposite that of a standard cut ring gear: Contrary to popular belief, it does not run backwards or in reverse. The principle behind a reverse cut is to strengthen the operation of the gear when it is used for a front driving axle application.

Hi-pinion or reverse-cut axles have also become very popular as rear driving axles in short wheelbase vehicles with suspension lifts because the higher pinion improves drive line angles so well. Dynatrac was among the first to pioneer this application and continues to offer the very best and strongest Hi-pinion axles available anywhere.

Standard-cut axles are often used as the front driving axles because of clearance issues, gear ratio availability, cost, or suspension considerations. However comparable reverse-cut axles have the distinct advantage of overall ring and pinion gear strength.

Reverse-cut axles should be used in the rear when higher ground clearance, reduced drive shaft angles or short wheelbase are desirable issues. Reverse-cut rear axles should be avoided for heavy GVW vehicles or heavy highway towing. Dynatrac has thoroughly tested Dana 44 reverse-cut, and Ford 8.8 reverse-cut, rear axles and found them to be weak and prone to failure in all but the very, very lightest duty applications. We can only recommend Dynatrac’s proven Dana 60 reverse-cut design as unquestionably dependable even under adverse situations.

The gear sets used in each type of axle are not interchangeable: Standard cut gears cannot be used in place of reverse cut, and vice versa. The housings, which have different lubrication passages, are also not interchangeable. However, differential cases (open, l/s, or locker) are compatible with both styles, as long as case spline count matches the axle shaft.

Taken from Dynatrac's website. Good basic info on the matter.
 
Robert 771 said:
Yeah, that's right...

Doh, they're right, I was wrong, read right past the "LP"

But I do think you should check with the shop about supplying your own gears. They normally make money on the parts, and shorting em on that, they may charge more for the install. They just might refuse the job altogether.

And who knows, they may get a better price than you can on your own...

Robert
 
Awesome, thanks for the tips and info! So am I right about going with 4.56's for 33's? Its my dd and light trail rig and I get real bad mpg's, I just want some gears that are somewhat even b/w trail and street.
 
MG2000XJ said:
Awesome, thanks for the tips and info! So am I right about going with 4.56's for 33's? Its my dd and light trail rig and I get real bad mpg's, I just want some gears that are somewhat even b/w trail and street.

You will be happy. Good setup for wheelin/pavement pounding.
 
Well, I'm "happy" with 456s and my 35s.

I'd be "thrilled" with a little more gear or less tire.

33s and 456s would be great.

Robert
 
Hey guys. I have a 98 with the 30 in the front and the 8.25 29 spline in the rear. It now has 3.55's I am wanting to go to 4.56's. I was told that unless my jeep came with 3.73's I would need a new carrier in order to change the ring pinion ratio's. Does anyone know if this is correct? If so why would they make a different style carrier just for one gear set that would not be compatible with any others? Any help is appreciated.Thankyou
 
your 8.25 carrier will be fine (same carrier all ratios - only difference is spline count 27 or 29), the D30 uses different carriers for higher or lower gear ratios - I believe the low ratio carrier is 3.73 and lower (higher number numerically)

Mike
 
So far youve got close,but bad info!The older jeeps use std LP gears,the 2000-01 XJ uses the newer "short pinion" TJ gear,which is completely different!
 
RCP Phx said:
So far youve got close,but bad info!The older jeeps use std LP gears,the 2000-01 XJ uses the newer "short pinion" TJ gear,which is completely different!


not trying to pick a fight, but could you clarify your answer??? because i think thing most everybody here will argue that the older jeeps (or XJ's specifically) use HP D30 gears. the LP D30 started being used around 00+.

or did i missunderstand what you said???
 
scorpio_vette said:
not trying to pick a fight, but could you clarify your answer??? because i think thing most everybody here will argue that the older jeeps (or XJ's specifically) use HP D30 gears. the LP D30 started being used around 00+.

or did i missunderstand what you said???
I was refering to like "CJ's".
 
Ok, the 8,25 will be good with the 4.56s, But my d30 will need to have a new carrier to go with 4.56s. because it currently has 3.55s. If that sounds, correct what is involved with getting the right carrier? Or what are my options on that and what do you guys recommend?

Thanks again.
Thomas
 
Whoever you get the gears from should be able to supply the carrier for the D30 - I believe it would be $75 or less new.

Mike
 
what about this???
fattmann1984 said:
im new to the site ,so hello ! i have a 2000 cherokee and i bought a set of 4.56 superior gear for it but im having trouble, with my d30 c8.25 combo. well frankly the gears are too tall and i cant get the spider pin back in ! rustys sold me a new carrier for the d30 and it is in even worse condition! the ring teeth are covering the spider pin hole in the carrier by 1/4 of an inch, has anyone else had this problem? any insight will help, tips or tricks getting the pin in place.:hang: :hang: :hang:

Others said grind the gears but whats up with that? Why buy a brand new set of gears and have to grind on them to get them to fit?
 
MG2000XJ said:
what about this???


Others said grind the gears but whats up with that? Why buy a brand new set of gears and have to grind on them to get them to fit?

For the front, install the cross pin, and then the ring gear.

For the C clip axles, you can buy an offset cross pin, or take a dremel tool, and grind down the one tooth that the cross pin will hit on. Its just they way it comes out. No loss in strength in grinding one tooth down for it to fit.
 
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