I'm going to gear the jeep in fall and was wondering what some people had for gears with the same set-up as mine. I have a 2001 tj 4.0, 3 speed auto, 33 12.5 dana 30 and 35. It's a daily driver with light offroading (no mud).
i have the stock 3.73s and with 31s i think its perfect, using that logic a 4.10 would land you in the same rpm ranges for offroad and highway use. If it sees less highway and more offroad you might be better of with a 4.56 but you would be screaming on the highway
Due to you not having an OD, 3.73 would really be best. 4.10 would work great but you'd be spinning higher RPM's on the highway. No big deal. Either way, try to find a set of axles from another TJ instead of paying for new gears.
Ghaniba is spot on. Go with a junk yard Ford 8.8 rear axle with 4.10 gears. I ran this set-up with 33s and it worked great. I would run about 2800 RPMs at about 60MPH with my 3spd auto. I just went to 35s with this set-up and I'm still happy with my acceleration.
I'm running 4.10's with that same trans/tire combo. It's great off road, and pretty decent on the highway. As stated about you'll run about 2800rpm at 60mph. Which puts you in a good place as far as the power band of the engine is concerned. Just expect to burn a little more fuel because of the higher rpms.
I'm running 4.10 gearing and I am happy with the performance both on and off the road.
1998 TJ Moss [COLOR=darkgreen][B][SIZE=3]Green[/SIZE][/B][/COLOR] Sahara w/ numerous scratches & dents whose playground is on a tropical island that's 33 miles long and 4-12 miles wide, in year-round 82 degree weather.
got a question about this too. Im going to school in upstate new york and the ride there is all up and down mountains. Im getting 33x12.50 dunlop muds and was wondering if 3.73 or 4.10 would be better for the mountains.
For the 3-speed automatic and 4.0L engine, 4.10 is appropriate for 33" tires and 4.56 is appropriate for 35" tires.
My TJ had 4.88 gearing and 35" tires when it had its OE 5-speed transmission. I converted it to the 3-speed automatic and its existing 4.88 gearing stayed. That ratio was too low for my 35" tires after installing the 3-speed automatic. I had to stay in the slow lanes because I had to slow down my highway speed to keep the engine rpms reasonable. 4.56 for my 35" tires would have been ideal but I wasn't going to pay again to regear it to 4.56. So 4.56 with 33" tires and the 3-speed automatic would be too low of an axle ratio, that combination would be just like my 4.88 with 35" tires.
Go with 4.10 for 33" tires and your 3-speed automatic, you won't be disappointed or have excessively high or low highway engine rpms.