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Axle gear ratio?

musikman43155

NAXJA Forum User
Location
Hocking Co., OH
I have a 1992 Jeep Cherokee w/ an AX-15. I tried looking @ the rear axle for a tag, but, cannot locate how the axle is geared.

I'm considering buying a Chrysler 8.25" axle to replace mine. His is also a 2 door 5 speed, but, a 1997.

I may also end up buying his front axle, but, I don't think there's any reason to, besides mine being rusty. It's still a Dana 30, right.

I am a complete amateur & have had my XJ for a short time. I appreciate any help.
 
96 or 98 and up is a L/P
you have a H/P front 30
but if you have a 5speed with the 4.0 it should have 3.07's

if he has a H/P front and a 8.25 rear out of a A/T 4.0 it has 3.55's
good and a little lower but you need both to keep you gears wright
 
- low pinion means the pinion is lower then the center line of the ring gear. (look at your rear axle where the drive shaft goes into the axle.)
- high pinion mean the pinion is higher then the center line of the ring gear. (look at your front axle where the drive shaft goes into the axle.)

Your pinion is internal to the axles differential. It is attached to the yoke, which is bolted to your driveshaft. Drive shaft spins, which spins the yoke, which is connected to your pinion, which turns the ring gear, which turns the "spidergears" (also called pinion gears.....lol im not trying to confuse you) which are connected to your axle shafts, which are bolted to your wheel , which is attached to your tire. There is a brief explnation of how your axles work lol.

Generally speaking, a high pinion(hp) front axle will be Stronger then it's low pinion(lp) counter part. This is because of how the ring and pinion gears (also refered to as R&P) are meshed together and how they transfer torque. Quoted from Wikipedia "Torque, also called moment or moment of force (see the terminology below), is the tendency of a force to rotate an object about an axis,[1] fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist."

a far as I know low pinion(lp) dana 30's came in 00-01xjs
all zjs and wj (grand cherokees)
all tj wanglers

a/t= automatic transmission
m/t= manual transmission
 
Engine size info on each Jeep would be helpful as well as knowing whether or not the spare on each was a full size from the factory.

As a general rule:
4.0L W/5spd used a 3.07 ratio
2.5L W/5spd used a 4.10 ratio

IIRC, Dana 35 was used on most applications until the Corporate 8.25 became standard in about 97' though instances of Dana 44s and Corporate 8.25 with 27 spline axles also occurred in some towing packages.

Front axles in both applications would be Dana 30 with a high pinion. The pinion orientation is important to people who desire the extra ground clearance offered by having the front u-joint on the top of the case instead of the bottom.

Brakes on the 98 are better than the 92 with larger pads and shoes being used.

A full sized spare was used on vehicles with a Trac-Loc differential to prevent failure caused by putting on one significantly smaller compact tire.
 
95+ has the dual diaphragm brake booster.

AX-15 would be a 4.0 engine and 3.07 from the factory.

If the 97 has a 2.5 cylinder engine it would be an AX-5 with 4.10s; if it is a 4.0 it would be an AX-15 with 3.07s.

As said, low pinion D30s introduced to the XJ in 2000.

Chrysler 8.25 introduced to the XJ 91+; 91-96 are 27 spline, 97-01 29 spline.

Always double check change years, they can be like a box of chocolates--you never know what is inside.
 
96 or 98 and up is a L/P
you have a H/P front 30
but if you have a 5speed with the 4.0 it should have 3.07's

if he has a H/P front and a 8.25 rear out of a A/T 4.0 it has 3.55's
good and a little lower but you need both to keep you gears wright
nope... 00 up is LP.

- low pinion means the pinion is lower then the center line of the ring gear. (look at your rear axle where the drive shaft goes into the axle.)
- high pinion mean the pinion is higher then the center line of the ring gear. (look at your front axle where the drive shaft goes into the axle.)

Your pinion is internal to the axles differential. It is attached to the yoke, which is bolted to your driveshaft. Drive shaft spins, which spins the yoke, which is connected to your pinion, which turns the ring gear, which turns the "spidergears" (also called pinion gears.....lol im not trying to confuse you) which are connected to your axle shafts, which are bolted to your wheel , which is attached to your tire. There is a brief explnation of how your axles work lol.

Generally speaking, a high pinion(hp) front axle will be Stronger then it's low pinion(lp) counter part. This is because of how the ring and pinion gears (also refered to as R&P) are meshed together and how they transfer torque. Quoted from Wikipedia "Torque, also called moment or moment of force (see the terminology below), is the tendency of a force to rotate an object about an axis,[1] fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist."

a far as I know low pinion(lp) dana 30's came in 00-01xjs
all zjs and wj (grand cherokees)
all tj wanglers

a/t= automatic transmission
m/t= manual transmission
fairly certain most ZJs (at least till the mid to late years) are HP, I'll have to take a look at my friend's 97 sometime. Not sure about WJs but they don't swap over to XJs anyways, different width and coil/link mounts and in some cases a different pinion yoke since they used those wonky CV front shafts on some years.

Engine size info on each Jeep would be helpful as well as knowing whether or not the spare on each was a full size from the factory.

As a general rule:
4.0L W/5spd used a 3.07 ratio
2.5L W/5spd used a 4.10 ratio

IIRC, Dana 35 was used on most applications until the Corporate 8.25 became standard in about 97' though instances of Dana 44s and Corporate 8.25 with 27 spline axles also occurred in some towing packages.

Front axles in both applications would be Dana 30 with a high pinion. The pinion orientation is important to people who desire the extra ground clearance offered by having the front u-joint on the top of the case instead of the bottom.

Brakes on the 98 are better than the 92 with larger pads and shoes being used.

A full sized spare was used on vehicles with a Trac-Loc differential to prevent failure caused by putting on one significantly smaller compact tire.
X2 except the 35 vs 8.25 info, at least in my area of the country, 8.25s are very very common even in the early years (well, early years for them - so 92 or 93 up) and I rarely see a 35 in an XJ unless it came with ABS.

Also, a full size spare does not automatically mean LSD is installed (I know you aren't saying this, just clarifying.) A donut spare from the factory would automatically mean LSD is NOT installed. However many vehicles came with fullsize spares and no LSD, and at this point the vehicle has probably had 2 or 3 owners and you have no idea how stupid/stingy they were, so I wouldn't be at all surprised to see a donut spare in a vehicle with an LSD because the owner wanted to spend 5 dollars for a new spare at the junkyard instead of 15.

Also there is NO crossover in years between the 44 and the 8.25... the 44 was available for sure in '87 and some people claim to have seen them in 88s, 89s, and 90s but 91 and up they are nonexistent (unless added aftermarket by a previous owner.) I'm not sure if the 8.25 was "standard" in 97 and up but would not be surprised, I know ABS implies a d35 in all years but like I said, I haven't seen enough non ABS d35 equipped vehicles in the yards here to form any sort of opinion that can be backed up with facts or statistics.
 
Engine size info on each Jeep would be helpful as well as knowing whether or not the spare on each was a full size from the factory.

As a general rule:
4.0L W/5spd used a 3.07 ratio
2.5L W/5spd used a 4.10 ratio

IIRC, Dana 35 was used on most applications until the Corporate 8.25 became standard in about 97' though instances of Dana 44s and Corporate 8.25 with 27 spline axles also occurred in some towing packages.



Brakes on the 98 are better than the 92 with larger pads and shoes being used.

Chrysler 8.25 started in the very early '90s. My '92 and '96 have them, but my son's '95 and '96 both have D35s, and they both have LSD (more initials!) Limited Slip Differential. The front brakes changed somewhere in the late '80s, not sure, but my '92 has the same ones they used until the end, as well as ZJs and TJs. There were some 10" rear drums early on, maybe with towing package, or possibly D44, but 9" is more common.
 
Chrysler 8.25 started in the very early '90s. My '92 and '96 have them, but my son's '95 and '96 both have D35s, and they both have LSD (more initials!) Limited Slip Differential. The front brakes changed somewhere in the late '80s, not sure, but my '92 has the same ones they used until the end, as well as ZJs and TJs. There were some 10" rear drums early on, maybe with towing package, or possibly D44, but 9" is more common.
Would your son's 95 and 96 have ABS? Personally, I haven't ran across an 8.25 with ABS yet, they've all been D35s.

The 10" brakes may have been part of a police package.
 
The only way you will ever find an 8.25 with ABS is on some Dodge vehicles (they use the single sensor mounted in the pumpkin though) or on Talyn's rig :thumbup:
 
Would your son's 95 and 96 have ABS? Personally, I haven't ran across an 8.25 with ABS yet, they've all been D35s.

The 10" brakes may have been part of a police package.

No, his '95 was a Park Ranger car from somewhere in north Jersey, and the only odd thing we've found on it was the wrong u-joints on the front axle. It has a D35 with Posi. His late '96 is a Classic, with Up Country package, and Towing Package, with a D35 Posi, but no ABS on either one. We're chasing an odd vibe in the '96, and according to a few threads, this was common, and there were TSBs about it, although not for '96, at least as far as AllData knows. I think we're going to end up putting an 8.25 in it.

All of the 10" deals I've seen are the Renix-era XJ Wagoneers and Limiteds, and those mostly came loaded up with options, including Towing, and probably D44s. Next time I see one, I'll have to take a closer look!
 
A full sized spare was used on vehicles with a Trac-Loc differential to prevent failure caused by putting on one significantly smaller compact tire.

A full size spare alone is not a good indicator- my 97, a friend's 96, and another's 95 all 3 had full size spares, and none had the TracLoc.
 
Why do you want to swap the rear? Just for the added strength? You might want to consider swapping in axles with different gearing if you plan on bigger tires in the future. For example the gearing in the 2.5l manuals was usually 4.11, and the autos 3.55 ratios. Definitely confirm what ration you have because mis-matching the front and rear will lead to breaking things. Also verify if its a straight swap or whether the mountings changed between those years.

The best advice I can give you is to figure out what you want to do with the Jeep, such as daily drivers or serious rock crawler. Then figure out your budget and what you will need. How high will you lift, tire sizes, etc. Start with the basics like solid recovery points front/rear.
 
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