Rear gearing ?

[manouso]

Well i've never owned a truck with an automatic or had a TJ.

I was talking to my girlfriend and she was wondering of ways to give her jeep(tj, with auto trans, 4.0L) more power. I am figuring that the most effective fix would be to regear the axles since she is running 33 inch tires, but i am not truely sure because i do not have a great understanding in how this works with a auto trans. If anyone could explain or give a sugestion, would be appreciated.

Thanks,

Manouso

 

[demon jeep]

what does she have for gears in the axles remember if you put lower gears in it will give more power to the ground but top speed will lower. I am going to run a 4.56 with 35" I will not go fast but I drive a jeep so no biggy

 

[Greg]

It won't give it more power, but it will feel like it has more power, since the engine can run in the RPM Range it's meant to, right off the line.

I would regear, and if you are going to spend the $$, don't throw 4.10's in. Go with 4.56's and call it good. No matter what you do to the engine, turning 33's on stock 3.73 or 3.55 gears is going to suck. Power and Gas mileage will improve w/ deeper gears. The Auto makes it easier to start out w/ 33's and crappy gears, but it probably takes longer for it to run thru the gears, ending in lower RPM's on the freeway.

 

[sukaB]

4:56's or 98 Vortech 350.......

 

[MR.CJ-7]

My cj is an auto I am running 33" tires, I opted for the 4.56's. It works well for my needs, 4.88's might have been better though, but mine is still an occasional daily driver.

 

[mbryson]

Originally posted by Greg
It won't give it more power, but it will feel like it has more power, since the engine can run in the RPM Range it's meant to, right off the line.

I would regear, and if you are going to spend the $$, don't throw 4.10's in. Go with 4.56's and call it good. No matter what you do to the engine, turning 33's on stock 3.73 or 3.55 gears is going to suck. Power and Gas mileage will improve w/ deeper gears. The Auto makes it easier to start out w/ 33's and crappy gears, but it probably takes longer for it to run thru the gears, ending in lower RPM's on the freeway.

What he said....I'm running 4.10's with 35" MT/R's and wish I'd never spent the time on the 4.10's. {of course it would help if my Jeep would run, right now}. I think you'll be OK with the 4.10 IF you stay at 33" tires. If there's even a possibility {and there is} of moving taller than that, go with a 4.56 or greater....

Originally posted by SukaB
4:56's or 98 Vortech 350.......

Absolutely NOTHING wrong with a Vortech (or L98 for that matter) AND 4.56 gears.

Speaking of that, anybody know local smog laws for engine transplants? (probably a whole other thread)

 

[mbryson]

I did just notice your 'Topic is ---REAR GEARING'.....

You're going to want to do both axles at the same time (you probably already know that, but if you didn't, another transfer case was saved......)