Made a call to Jeep today. Called the number on the original window sticker. I wanted to find out what type of axles it has and if it has Veri-Lok. You would think after 10 years I should know and that it has 3.55 gears. It does not have Veri-Lok so that was nice to finally know. Not knowing that shops claimed it required synthetic fluid (no towing here) and it doesn't.

The front axle is a Dana 30, Rear is a Dana 35C.

Why didn't Chrysler use a 3.27 gear set-up for better fuel economy?

I remember Mustang guys swapping 3.27s for 3.55s and I was like if your going through all that at least go 3.73s...just my 2 cents

 

A little clarification here. The build sheet of my '00 WJ also says Dana 35C although it has a D35 without the c-clips. The axle bearings are Timken cartridge bearings, not the flat rollers of the 35C. You can pull an axle without opening the diff.

You are forgetting that 4th gear is overdriven so the rpms are lower at speed so the mpg is comparable to using 3.27 gearing. The 3.55s give you grunt at lower speeds.

I'm using 75W-140 Syn in my open rear diff just because it's mainly used in 2WD and I want to make it last. It contains a friction modifier as well.

IDK about Mustangs, but my Camaro had 4.10s in the rear axle and in order to use them it had to have the 12-bolt axle in it.

 

Try this. They get back to you really fast. On weekdays. They tell you everything about your Jeep.http://www.jeep.com/webselfservice/j...ull&category=U

 

You can also check out wjjeeps.com for lots of info about your jeep. They even tell you how to change light bulbs!