Gearing advice???

[Gsx31337]

I have a 01 TJ Sahara edition, with a 3 inch teraflx short arm lift on it running 32x11.5 Goodyear MTR's .. I do a fare amount of off roading with it but also a lot of highway driving with the 70MPH speed limits... if there is any head wind at all I cant get it to break 75 unless i shift the auto transmission into second gear. at 70MPH im only running about 2100-2200 rpms.. I cant say for sure but im guessing im running 3.73's I instaled a K&N cold air intake, helps with get up a bit but cant tell much difference with the top end. I got an extra 200lbs or so with a warn front bumper and 9000lb warn wench which I doubt makes much difference. I have a 30 in the front and a 35 in the back and am looking at regearing, with my next tire change Ill pry just throw on 33's.
Will I notice much difference with 4.10's or should I go for 4.56's ? or will that be running my RPM's to high around 80 mph?

 

[Bounty__Hunter]

Sounds like you may have 3.07 gears, I'd check the digits on each diff cover tag to be sure. If you have 3.07, regear to 4.11. If you have 3.73, I'd recommend regearing to at least 4.56.

Correct me if I'm wrong, but isn't the '01 TJ auto transmission still a non-overdrive 3spd transmission?

 

[Gsx31337]

Im not sure but, I wouldnt think they would put 3.07's in a sahara with an Auto transmision. ? I'm out of town now for a bit but ill look that up when i get back.

 

[TwistedCU]

The 4 speed auto trannies are packaged with 3.73 gears (barring the Rubicon pkg but they didn't come out until '03).

I would verify that before buying anything.

If you do in fact have 3.73, which I am pretty sure you do, there would be very little difference with 4.10 gears. Go with at least 4.56 as your overdrive transmission will need the low gears to turn those 33's at highway speeds.

 

[Bounty__Hunter]

He has an '01, what year did the TJ go from a 3spd auto to the 4spd auto with OD?

I plugged his known specs into a gear calculator, 32" tires, guessing 3.07 axle gears with a transmission ratio of 1:1 gives 2256.5 rpm at 70mph.

Switching to an overdrive transmission, guessing a .78:1 transmission ratio with 3.73 gears, gives a 70mph rpm of 2138.4.

Both scenarios are close to what he's experiencing while driving so I guess a lot depends on if this transmission is OD or not.

 

[TwistedCU]

He has an '01, what year did the TJ go from a 3spd auto to the 4spd auto with OD?

Not 100% certain, but I think it was 2000.

 

[Gsx31337]

I got a 3 speed in mine, Um I think they did the 4 speed change in 2003...

 

[Utah_jeepster]

DC doesnt offer a 4 speed in any TJ...only the Rubicons in 2003 and later had them.
The LJ's and JK will have them as well

 

[Bounty__Hunter]

The Rubi is a TJ, and I thought they switched the entire Wrangler line over to a 4spd beginning a certain model year 2001 or later.

 

[currupt4130]

http://www.grimmjeeper.com/gears.html

 

[TwistedCU]

Yeah, they did switch to the overdrive 4 speed in '03. I think it is the same AW4 that I had in my 2000 XJ.

Wow, that's a nice calculator Currupt!!!

 

[currupt4130]

Yea, he just updated it. He's got all sorts of tricks worked into it, its pretty cool.

 

[Bounty__Hunter]

I plugged his known specs into a gear calculator, 32" tires, guessing 3.07 axle gears with a transmission ratio of 1:1 gives 2256.5 rpm at 70mph.

With 3.07, I'd recommend regearing to 4.11 with 32" or 33" tires to get your performance back.