Topic: ReGearing for your 4banger v1.02

[Jeffy]

The previous list was set up using older information and not taking into account what some of the more minority Jeeper might have.  Below are optimal gearing to bring it back to stock like performance.  As always, if you want a little more torque you can go with one gear set lower.  On the other hand, if you cruise more, you can always go with one gear set higher.  You will want to double check anything listed below with something like the Gear and Tire applet at www.jeeptech.com.  ( http://www.jeeptech.com/javaAps/gta.html )  You will need to know each gear ratio for the transmission, transfer case and rear axle.  Once that's plugged in, it will chart out the RPM's for any given speed.  For most you'll want to look around 3000 rpm for optimal power.

Here's the breakdown.

Engine     Transmission     Gears
(YJ Wrangler, TJ Wrangler, XJ Cherokee and MJ Comanche)

2.5L | Manual |  4.10/4.11:1
2.5L | Automatic | 3.73:1

Optimal Gearing:

Manual  |   Automatic   |  Tires
4.56 | 4.11 | 31 inch
4.88 | 4:56 | 32 inch
5.13 | 4.88 | 33 inch
5.38 | 5.13 | 35 inch
5.89 | 5.38 | 37 inch

Now there is a slight problem with the 2.4L's.  Early on they used an NV1500 5-speed transmission with the same gears as the 2.5L.  The automatic was a 4 speed with OD.  Then later they came out with a 6-speed manual from the Mercedes.  The stock gearing on the newest 2.4L's with the 6-speed is now 4.56.

Engine     Transmission     Gears
(TJ Wrangler, KJ Liberty)

2.4L | 5-speed Manual |  4.10/4.11:1*
2.4L | 3-Speed Auto | 3.73:1*
2.4L | 4-speed Auto | 3.73:1**
2.4L | 4-speed Auto | 4.56:1
2.4L | 6-speed Auto | 3.73:1**

(*use 2.5L Chart above.)

Optimal Gearing:

Manual  |   Automatic   |  Tires
4.88 | 4.88 | 31 inch
5.13 | 5.13 | 32 inch
5.38 | 5.38 | 33 inch
5.89 | 5.89 | 35 inch
*** | *** | 37 inch

** Optimal Gearing:

Manual  |   Automatic   |  Tires
4.10 | 4.88 | 31 inch
4.56 |        | 32 inch
4.88 |        | 33 inch
5.13 |        | 35 inch
5.38 |        | 37 inch