i have access to free parts from a 1998 jeep cherokee classic with the 4.0l . i currently have 2.45 gears in my 8 1/4 rear right now. i'd like to swap in the differential from another rear to get a little better ratio. will the diff work from this car if it has the 8 1/4 rear? and what ratio would i be looking at from a cherokee? thanks for your help.


casey

If I remember right there was spline change in the axle shafts in 1994/1995-ish... so you can't just drop the center section into your 8 1/4" and call it good... if it is an 8 1/4" you can pull the ring and pinion and have someone mate that to a 2.76:1+ ratio open center section or buy the appropriate sure grip unit...

You'll have buy a kit and run the pattern to get your 8 1/4" setup right as it's not as nice as setting up the 8 3/4"...

If you daily drive with an automatic and the Jeep has 3.55's/3.73/3.91 rear gearing you will have lots of 'pep' and lose lots of gas mileage...

I have one of those open center sections with a 2.71 ring mated to it (no pinion though)...would let it go for cheap if you pick up...

If I remember right there was spline change in the axle shafts in 1994/1995-ish... so you can't just drop the center section into your 8 1/4" and call it good... if it is an 8 1/4" you can pull the ring and pinion and have someone mate that to a 2.76:1+ ratio open center section or buy the appropriate sure grip unit...

You'll have buy a kit and run the pattern to get your 8 1/4" setup right as it's not as nice as setting up the 8 3/4"...

If you daily drive with an automatic and the Jeep has 3.55's/3.73/3.91 rear gearing you will have lots of 'pep' and lose lots of gas mileage...

I have one of those open center sections with a 2.71 ring mated to it (no pinion though)...would let it go for cheap if you pick up...


-D.Idiot

it's true the later model 8 1/4 had more splines, and also thicker c-clips. the MP kit for setting up a new ring and pinion is nice since there is a selection of shims to set the pinion depth, but only has one crush collar and no marking compund. be sure to buy a few extra collars (they're cheap) in case of a screwup. i'm also thinking the 2.45 gearset uses a special diff due to the ultra-tall gear, so a new diff will be be in order. time for a sure grip!

-james

_________________

If the Cherokee has rear disc brakes and the diff housing isn t bent,,,you might want to measure for a complete rear axle swap....weld some perches....change master cyl...

_________________
Yeah....Im the one who destroyed this rare, vintage automobile.....

so what is my best option for putting a little better gearing in my rear end? i'd like something like 3.21 gears. not too big, but enough to spice it up a little. so DI, what would the open center section with the 2.71 pinion mated to it do for me? thanks.


casey

It would allow you to use any 2.71+ ring in your current axle...


Option 1)
Measure the rear out of the cherokee, if it's close, put under car, reweld perches to match leaf springs, hook up brakes, may need prop valve to make it work properly with your current brake setup. Buy a new speedo gear for the tranny...

Option 2)
The current 2.45 carrier will only support gear ratios of the 2.24 and 2.45 'mileage' rings... to fit any 2.71+ ratio in your rear you have to have the carrier out of a 2.71+ pre-94 8.25 rear....
Once you pull the ring and pinion out of the cherokee, and lay your hands on a 2.71+ center section and a kit, a professional will be able to mate your ring to the carrier, install the pinion, set the depth, run the pattern, correct if necessary, and you are good to go...

8.25" is a nice one to get gears easy and sometimes junkyard sure grips (used in lots of trucks), but it isn't friendly like the 8 3/4" to just 'plug and play' a chunk...

weld and fool with it or pull two axle assemblies apart and get a new carrier to make one...

rock or a hard place...

-D.Idiot