Gearing question

[DDAWG3953]

I'm considering getting my Jeep re-geared but I'm not sure what ratio I might need or what this will involve. I have a little 2.5 liter in a 95 YJ. I like the little guy but now that I've lifted it I don't think enough torque is being transfered to the wheels. I only lifted it two inches and put 31" on it. My current ratio is 3:73. Any advice is appreciated.

[02tj]

with a 4cyl and 31's Im assuming ya have a ax5 trans and a 231 x-case, I would gear her down th 4:56

[Wildman]

The first question you need to ask yourself when trying to decide gears is this; Are you going to go any bigger in tires size? If the answer is yes then gear for your planned size. Due to the cost to regear you only want to do it once.

If you have 3.73 gears you have an auto tranny?
If your staying at 31" tires then yes 4.56 gears are good.
If your going to go to 33" tires then regear to 4.88.
With your stock axles you can't go any lower than 4.88.
5.13 are good for 35" tires but really 5.38 is better. Now all this info is for a 4 cyl. For the 6cyl guys your gearing is different.

[TexCJ7]

here is a chart that should help you

http://www.4x4offroads.com/gear-ratio-chart.html

in the chart the green highlights are close to stock and the red is for power and performance

[korisu56]

Good pull on the chart.

X2 million on what wildman said. It's a costly PITA to do it, so do it once.

[ArmyFSJ]

I would go with the 5.13 or higher on anything with bigger than stock tires on it with 4 squirrels running it.

[TexCJ7]

as much sense as that makes there should be no reason to treat it any different that if it had the 4.0 in it because when they come from the factory they have the same gears no matter then engine

[korisu56]

But the differences in power will be amplified with the increased amount of stress on the motor. While you may only feel a slight difference with 29" AT's, the difference at 35" could be rediculous. I, as usual, have no way to back this up just a guess.

[treefrog]

as much sense as that makes there should be no reason to treat it any different that if it had the 4.0 in it because when they come from the factory they have the same gears no matter then engine

Not really. In YJs and TJs all 4 bangers with 5 speeds got 4.10s from the factory. I'm not sure on the autos though. 4.0s got either 3.07s or 3.73s depending on trannies. Only Rubicons got 4.10s with the 4.0.

[korisu56]

Is my post way off the mark?

[TexCJ7]

lets say you have a motor that makes 200hp at the rear wheel and one that makes 400hp at the rear wheel and they are both in the same "jeep" running 4.10 gears and you switch to say 5.13 the horse power difference should still be the same


the gears are not going to make the 4 banger more power just take the power and make it more useable

[treefrog]

Is my post way off the mark?

No, not at all. I have owned a 4 banger with 4.10s and 33s and my current ride has the 4.0 with 4.10s and 33s. There is no comparison. The 4 banger just doesn't have the torque that the 6 has. If I were regearing a Jeep with the 4 banger, I would go straight for the 4.88s if I were going to be running 33s. It will be a little buzzy at highway speeds, but if you want it to get out of it's on way, that's what it will take.
And remember, what I consider a "little buzzy" may not be what others would consider a "little buzzy".
And right now the Yuenglings are telling me that I am a little buzzy.:)

[trailsnail]

Thanks for the chart, good link. For some odd reason, I thought that I had 4.10 gears. Don't I feel dumb.

[DDAWG3953]

Ok, thanks for the chart and the advice. Now I guess I need to find out what parts will be required and/or are there parts kits available that have all the goodies needed

[korisu56]

If you get the gears and "master install kit" then you'll have everything needed part wise. Some can do it without the install kit if they have extra crush sleeves, but I dunno that much about it. When we re geared my 8.8, we used the kit and an extra crush sleeve.