Chryco 8.25 Typical Ratio

[Zenobian_84]

As the title states, what was the usual gear ratio found in the HP 8.25s (97+ XJs)

 

Figured if I don't decide to add 4x4 to the old girl, I can at least upgrade the rear end to something respectable.

 

The 8.25, coupled with an AX-5 should be the very last upgrades I do to this truck; getting sort of tired of the 4-speed, TBH.

 

The reverse can also be said as well :yes:

[Biotex]

Chrysler 8.25 - 29 spline, 1.21" diameter shafts, 8.25" ring gear, 3" axle tube - used 97-01

 

3.07 - used with 4.0L engine / manual transmission

3.31 - only available on older (pre87?) 2 door XJs with "Fuel Economy" package

3.55 - used with 4.0L engine / automatic transmission

3.73 - found in some XJs with the towing package

4.10 - used with 2.5L engine usually, and older XJs with the "Off-Highway Vehicle" package.

4.56 - rare but can be found on some older (~ 89 ~) models with 2.5L engine and auto transmission

[Guest]

Thanks!

 

Any way to tell a "Towing Package" XJ from a regular one? Aside from the gear tag on the housing, that is.

 

Would love some 3.73's back there; I've given up on getting 4.10s.

[mvusse]

Chrysler 8.25 - 29 spline, 1.21" diameter shafts, 8.25" ring gear, 3" axle tube - used 97-01

 

3.07 - used with 4.0L engine / manual transmission

3.31 - only available on older (pre87?) 2 door XJs with "Fuel Economy" package

3.55 - used with 4.0L engine / automatic transmission

3.73 - found in some XJs with the towing package

4.10 - used with 2.5L engine usually, and older XJs with the "Off-Highway Vehicle" package.

4.56 - rare but can be found on some older (~ 89 ~) models with 2.5L engine and auto transmission

 

3.31 and 4.56 would not be found stock in an 8.25. 3.73 is also a common ratio for ZJs, but AFAIK they didn't get the 8.25.

 

90% or more 8.25 axles from under Cherokees will have 3.55 gears. 4 cylinder ones would most likely have 4.10 gears, there may be an oddball 3.07 8.25 here and there if you come across a stick shift 4.0.

 

29 spline shafts started late in the 96 model year, (same time they started using the 97 electrical harness, even though it was still the older body style?)

 

Gear sets for 4.56 and 4.88 are also available, but not found under a stock vehicle. Available gear ratios go as high as 2.76, although that ratio uses a carrier specific for just that ratio.

[Eagle]

Chrysler 8.25 - 29 spline, 1.21" diameter shafts, 8.25" ring gear, 3" axle tube - used 97-01

 

3.07 - used with 4.0L engine / manual transmission

3.31 - only available on older (pre87?) 2 door XJs with "Fuel Economy" package

3.55 - used with 4.0L engine / automatic transmission

3.73 - found in some XJs with the towing package

4.10 - used with 2.5L engine usually, and older XJs with the "Off-Highway Vehicle" package.

4.56 - rare but can be found on some older (~ 89 ~) models with 2.5L engine and auto transmission

 

Chrysler did not own Jeep until early 1988, and no Chrysler axles were used until 1990 or 1991. There were no XJs or MJs with a 3.31 ratio that used a Chrysler 8.25" axle, and I very much doubt there were any with the 3.73 ratio. All you're going to find is a few with 3.07 from 4.0L 5-speeds, a lot with 3.55 from the 4.0L automatics, and some 4.10s from the 4-banger.

[Geonovast]

I don't think there's an HP 8.25. I don't recall ever seeing an HP rear axle.

[Pete M]

I've given up on getting 4.10s.

 

car-part.com shows a couple 4.10 '97+ 8.25s for $200-250 in florida. :thumbsup: both within 2 hours of ya.

[Akula69]

:dunno:

 

The 99XJ that we bought for our 89MJ-99 conversion came with a 8.25 and the the factory towing package, and although I have not been in the pumpkin yet the tag says its a 3.73 (axle tube is bent on that one). The one we picked up a week ago at the yard came off a 96XJ 2 door with the factory towing package and it does have the 3.73 on the tag and inside.

[Eagle]

:dunno:

 

The 99XJ that we bought for our 89MJ-99 conversion came with a 8.25 and the the factory towing package, and although I have not been in the pumpkin yet the tag says its a 3.73 (axle tube is bent on that one). The one we picked up a week ago at the yard came off a 96XJ 2 door with the factory towing package and it does have the 3.73 on the tag and inside.

 

Interesting. My wife's 2000 XJ came from the factory with a tow package (I should know, I special ordered it) and the axle ratio is 3.54.

[jpnjim]

The only reference I've ever seen to 3.73 geared XJ's was a note in the 93-94ish Brochures.

 

This was during the time period that tow package 4.0L ZJ's used 3.73's.

 

 

Only problem is I never found any reference to 3.73 geared 1993/4 XJ's anywhere else (even in the parts books).

If they never made the parts, how could they get put in the Jeeps?

(ZJ's used low pinion D30's that wouldn't fit XJ hp30's)

I've always figured it was a misprint and doubted XJs got 3.73's in 93/4.

 

Akula,

the info below was pulled from every source I have,

and none of them showed 3.73s in 96 or 99;

 

 

 

^^^If you do have a 199X's XJ with factory 3.73's,

post up some pics and I'll change the chart.

[Pete M]

Good ol' Jeep. always keeping us on our toes. :rotf: