I have a few questions about regearing and would like to see if ya'll could answer them. I've been searching for a while both online and talking to people who own a shop. I have a Chrysler 8.25 rear axle and a dana 30 front. I'm currently at 3.55s. I'm running 31s now but I can definitely see going to 33s after these wear out. I pull a trailer often and I do go on the highway quite a bit.

Here's the questions:
If I went to 4.56 with 31s how bad would it suck at highway speeds? Obviously I would have a pretty good bit of torque which would be nice. And how would mileage be? Worse than now or better? Just guesses or personal experience won't hold anyone to any answers.

Does anyone know a shop around Greenville, SC that wouldn't charge an arm and a leg to regear, or someone willing to help out a fellow jeeper. I don't mind getting my hands dirty just heard this is a big task that should be done by a pro.

Also, I only need gears for the rear but need gears and a carrier for the front correct? And where should I get them from?

I think that is all the questions. Thanks in advance for any replies!

 

4.56 with 31s at 65 is about 2400 rpm.

http://go.jeep-xj.info/HowtoSpeedoGears.htm

It's broken down pretty well towards the end.

 

If that is how it is used and what you have planned the 4.56's will be a perfect fit for you. I have ran 4.56's them with 31, 33, 35's and even with the 35's they work OK. With your current 31's you will notice a lot more power when pulling a trailer or on any hills and the trans should not be overheating either or up/down shifting a lot if running an AW4.

 

how were the 31's on the on the highway with 4.56? That's the main thing I'm concerned about. I don't want to go too deep. And how much did you pay to regear?

 

I don't remember the exact RPM's now with the 31" tires been a while but not all that high. Remember 4.10's with 31's are the same as a stock gear and tire are. One thing for sure it will not be a slug as if running 3.55.


The cost of the gears for both the D30/Chy 8.25 was under $500 for the 4.56's including quality master install sets also from Rustys. My local Jeep shop installed my gears and lockers for $200 per differential and did my SYE at the same time all in the XJ.

 

so it would be almost like if I had factory 3.73s having the 4.56 on 31s? That's a good price. Wish I could find that around here. Thanks for the replies!

 

Buy and install the gears, List your 31's on craigslist, Have the buyer meet you at the tire shop, buy and install the 33's so you minimal time with the gear spread is reduced and hand over the 31's upon dismount.

 

Knowing I was going to 35s in the future I regeared to 4.88s with 31s. I drove it almost 2 years with 4.88s and as long as I kept it below 3000 rpms I got 17mpg. Along with the gears I bored my throttle body to 60mm and was fortunate enough to get a spectre cowl intake before they stopped making them. The torque was incredible and a fully packed jeep pulling a 12' popup rarely needed to downshift in the hills of missouri. Now that I'm on 35s I miss the torque.

 

well there's more to be done before I can get 33s. I mean you never know might really like 31s and 4.56s.

 

No closer to a 3.90 gear is what it would be instead of a 3.73. The costs are lower in my area than a lot of places and this shop has been around a very long time he has a custom built Crawler and a Cummins diesel 99 XJ of his own along with a half dozen others all very nice. I have him do about all my work on the XJ and our diesel trucks.

 

Anything is better than 31s and 3.55s.

 

Been trying to find shops around here that do gears. The two lowest prices I've gotten are $1600 from a shop an hour away, and $1500 from a shop 30 minutes away. The $1600 offer was very vague and didn't really explain much or seem to tell anything. The $1500 guy said timken bearings Yukon gears 1 year warranty master install kit. And he'd do outer bearings and seals on the rear axle for $25 extra a side. So basically $1550 for a complete rebuilt rear axle and front axle (minus front hubs but I just did those not long ago).

 

That's about $650 more than I paid for everything you know what the gears and install kit will run they are under $500 from Rustys so over a grand for labor. That is high in any area ask him how much for labor if you buy the gears and install kits. That is what I do on most of my parts I have installed.

 

he said he doesn't typically do it that way because people have brought him bad kits that weren't complete then he had to go find parts. If I found a kit I knew was 100% complete I'd ask him that way.

 

28/31 x 4.56 = 4.11
28/33 x 4.56 = 3.86

You can run the 4.56:1 with 31" tires, your rig will feel and act like it has 4.11's in the rear meaning your cruising RPM's will be higher but its bearable until you swap to 33" tires.
With the 33" tires and 4.56:1 gears, your rig will act and feel like it has 3.86:1 gearing (like a ZJ with 3.73:1 gears does)