I just bought a 2003 wrangler with a 4" lift and 35 x 12.5 M tires.

Question

the power loss is significant. what can be done to restore power to the vehicle? I believe the gear ratio is 3.07. It was suggested that I change this to 4.56. is this reasonable? what else should I consider for options?

Answer 1

4:56 will do the trick. Is it mannual or auto?

Answer 2

4:56 gears are the way to go. 4:88 will not let you cruise over 60 on the freeway. The stock gear ratio should be 3:55 or 3:73 if it is an inline 6. 4:11 if it is a 4 banger. I have been regearing Jeeps for over 10 years and I always recomend 4:56 with 35" tires. I also own many of my own Jeeps.

Answer 3

If stock gear is 3.07 and stock tires are 30's then 4.30's will be close to stock ratio, BUT I think the 4.56 may be the way to go, a lil extra torque is great! Only a 4'' lift? Off road you must have a good bit of rubbing unless you shaved your flares a good bit (or maybe a 2'' body). Anyway, if you have a 35'' tire on the back and on the stock tire carrier, change it before it messes up your back gate(too heavy).

Answer 4

you change the gears you'll lose top end and gas mileage.  I'd look at a V6 engine swap, maybe with a supercharger or turbo?  The lil freshen ups are helpful as well, or maybe, just maybe, you can have the engine in it rebuilt?  Put into it a can of "Restore" to just get even cylinder pressure.  Besides that, check a local speed shop about a rebuild on the engine for some more power.

Answer 5

Your power loss is due to the 3.07 gearing and the 35"tires. You should regear to 4.88 to get your power and MPGs back. btw, you'll need to get a new speedo gear so that your speedo and tach will read correctly.

4.56 gears would work for 33" tires and would be borderline for 35" tires.

Happy Trails!