I have with regrets now a 96 cherokee, 4.0, 5 speed, 8.25 chrysler, with the dreaded 3.07. The lock nut came off on the rear dif at about 50 mph. pulled over with out a problem. Tow trucked it home, driver busted a couple teeth when unloading. Need to replace R and P. Can't find any for less then $600 for just the R and P. $1200 +- for the whole axle. Can I just change out both the front and rear R and Ps and change the ratio? If so whats best for gas Milage?

 

I can tell you have never heard of a JY.

For less than $500 you could have "new" axles, front & rear with 3.55's or 4.10's.

 

Get both front and rear diffs out of a Cherokee with an auto trans. Get the speedo driven gear from the transfer case, too.

 

OK, so what is a JY?

 

Junk Yard

Used Parts Emporium

Wrecking Yard

Salvage Yard

Auto Wrecker

Pick A Part

 

Instant 355 ratio upgrade ....410s if ya find 4cyl

 

And what years Automatics?

 

Thanks guys. Still new at this. Glad I have masters like yous guys. Cant believe I thought JY was a jeep model. POM.

 

I knew that's what you were thinking!! LOL.

 

Most all inline 6 motors with auto will have 3.55's. Most all 6's with 5 speeds have 3.07. The 4 cylinder 5 speeds are 4.10 older ones possibly have 4.56.

You need to look for axles out of a 96+ for the non-disconnect front axle bigger U joints & a 8.25 with 29 spline shafts.

The non disc axle has a smooth tube on the passenger side. The 8.25 will have a "lip" built into the pumpkin (below the diff cover).

You are close. Jeep made a YJ, or square headlight Wrangler.

 

Here's the front axle with the vacuum motor which Big David is suggesting you avoid.

 

x2!

That CAD disco sucks. Dumbest thing ever slapped into the XJ. Mine failed during a snow storm while my wife was driving it when I was at work. Her grandpap luckily was following and pulled her up the hill into our old townhome. Had to replace in the freezing **** cold and snow and ice. SUCK. Almost as bad as drums (which I soon will be rid of!).

 

So as I was driving home last night, listen to the clackety clack noise my chero makes now, sounds like a train going down the tracks, I started pondering the ratio principle in my head. My 3.07 means my pinion turns 3.07 times for every 1 turn of the ring? So the larger the ratio such as the 3.55 my motor will "think" its going further than it realy is. I have been getting 20 miles to the gallon. And get this. With the AC on doing 85, I was getting 21 MPG. I figure its a computer thing. Anyway, I guess I will lose that mileage benifit. But in exchange I will get more torque? Your thoughts?

 

You're still driving it with a broken ring gear?!


From 3.07 to 3.55 I doubt you'll notice a difference in fuel economy. Not much anyway.

 

Makes a difference in driving at least on stock tires with a stick, 35 MPH in 4th will go from ~1250 RPM to ~1450 RPM.

Good time to get some larger tires