jackel18 Posted October 18, 2007 Share Posted October 18, 2007 i have a D44/3:55 that i am going to be putting in my truck soon. This is what i have now, 4.0/AX-15/D35/3:07, 235/75/15. i have Crappy acceleration with this set up. the truck is going to be getting 31x10.5's Will the 3:55's be a good combo with the AX-15, and 31's? not so much looking to go mach 1, i just want my truck to have some balls again. oh yea and possibly pull a small camping trailer comfortably thanks guys Rich Link to comment Share on other sites More sharing options...
UNL1MTD Posted October 18, 2007 Share Posted October 18, 2007 jeep gears the Tj with 3.73 with 30" tires and 4.10s with 31" tires. 3.55 will be better than 3.07s but with the manual I think you will be better suited with 4.10s. I run 4.0L, 4.10s with 31s and an AX5 and I think the gearing is perfect. Has normal acceleration and has plently of grunt to drive with a full bed. Not hateful on gas either. I am averaging 18 on my 2wd. Link to comment Share on other sites More sharing options...
sinnaevd Posted October 18, 2007 Share Posted October 18, 2007 I had 3.55's in mine with my AW4 and my 31's Mine had tons of power. wasn't too bad on fuel either towards the end when I babied it. Edit: 4.0L as well. Link to comment Share on other sites More sharing options...
carnuck Posted October 18, 2007 Share Posted October 18, 2007 I have 33/9.50/15s on stock rims with an SOA, BA 10/5 (still haven't got the tcase in yet) and 3.73 axles. It acts just like it did 100,000 miles ago with stock tires and 3.07 gears. Hauls @$$, gets nearly 20 mpg loaded (gets 20 mpg w/o the canopy) and I just used it to move my '70 IH 5 ton in the yard (clutch is nearly fried already so I didn't have much to lose. Pull started the big brute and my MJ is still drivable!) Link to comment Share on other sites More sharing options...
feerocknok Posted October 18, 2007 Share Posted October 18, 2007 I have 33/9.50/15s on stock rims with an SOA, BA 10/5 (still haven't got the tcase in yet) and 3.73 axles. It acts just like it did 100,000 miles ago with stock tires and 3.07 gears. Hauls @$$, gets nearly 20 mpg loaded (gets 20 mpg w/o the canopy) and I just used it to move my '70 IH 5 ton in the yard (clutch is nearly fried already so I didn't have much to lose. Pull started the big brute and my MJ is still drivable!) It'd do better with 4.10s or 4.56s. Link to comment Share on other sites More sharing options...
Eagle Posted October 19, 2007 Share Posted October 19, 2007 Will the 3:55's be a good combo with the AX-15, and 31's? not so much looking to go mach 1, i just want my truck to have some balls again. oh yea and possibly pull a small camping trailer comfortably Nope. Not horrible, but not good. I had bought a set of 3.73 gears with the intention of running them in my XJ with 30" tires. Things changed, and they ended up in an MJ running 31x10.50s. The true final drive ratio (as evidenced by RPMs at MPH) is exactly the same as a stock automatic with 3.54 gears and stock 225/75 tires. 3.54s with 31s won't even get you back to the equivalent of stock tires with the 3.07s/ 3.73s are a good choice with 30" tires. IMHO 4.10s are about optimum for 31s in a multi-use vehicle, and you can go to 4.56 if the vehicle doesn't see a lot of highway cruising. Link to comment Share on other sites More sharing options...
offroader461 Posted October 19, 2007 Share Posted October 19, 2007 i have two setups between my XJ and MJ: MJ is 32" with 4.10's (4.0L 5spd) great acceleration but could have a better top end...it will be better when i get my 6" kit and 33's on it XJ is 32" with 3.55 (4.0L Auto) great all around...good acceleration and highway speeds really i don't prefer one over the other but i did notice a HUGE difference in my MJ when i went from 3.07's to 4.10's...totally night and day Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 19, 2007 Share Posted October 19, 2007 Will the 3:55's be a good combo with the AX-15, and 31's? not so much looking to go mach 1, i just want my truck to have some balls again. oh yea and possibly pull a small camping trailer comfortably Nope. Not horrible, but not good. I had bought a set of 3.73 gears with the intention of running them in my XJ with 30" tires. Things changed, and they ended up in an MJ running 31x10.50s. The true final drive ratio (as evidenced by RPMs at MPH) is exactly the same as a stock automatic with 3.54 gears and stock 225/75 tires. 3.54s with 31s won't even get you back to the equivalent of stock tires with the 3.07s/ 3.73s are a good choice with 30" tires. IMHO 4.10s are about optimum for 31s in a multi-use vehicle, and you can go to 4.56 if the vehicle doesn't see a lot of highway cruising. Agree. I am running 4.10s (actually 4.11s from Yukon) w. 31" tires, and the ratio is perfect for me. I do 90% highway driving and my mileage actually went up about 2 MPG when changing from the stock 3.55 ratio. Acceleration is much better, and the approx. 250 higher RPM at highway cruising speed creates better economy. But I have the AW-4 with O/D, so that helps too.............. Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 19, 2007 Share Posted October 19, 2007 honestly, if you feel like your truck has no power and 'no balls' with 3.07s and 235s... there's something wrong with your 4.0 cause i've got the same setup and it hauls @$$. fun as hell to drive, and pretty quick... not to mention i have the BA10 which has a higher first gear than the AX15 Link to comment Share on other sites More sharing options...
carnuck Posted October 19, 2007 Share Posted October 19, 2007 Mine won't do better than 20 mpg with 4.10s. The MPG dropped to 15 when I tried and the truck lost all bottom end power for takeoff. It felt like it couldn't get oit of it's own way! Remember mine is 3.07 originally, and with a quick check, 3.73 with 33" tires is the same equivalent ratio as stock tires with 3.07. Add some HO injectors and your rig will have some balls again! Link to comment Share on other sites More sharing options...
jackel18 Posted October 19, 2007 Author Share Posted October 19, 2007 honestly, if you feel like your truck has no power and 'no balls' with 3.07s and 235s... there's something wrong with your 4.0 cause i've got the same setup and it hauls @$$. fun as hell to drive, and pretty quick... not to mention i have the BA10 which has a higher first gear than the AX15 my truck is pretty quick, i want to be able to KNOW i can pass someone going up a hill and not THINK i can. get what i'm saying? Link to comment Share on other sites More sharing options...
Duner Posted October 19, 2007 Share Posted October 19, 2007 I think its time to look at your 4.0 and not your gears, does your engine feel lifeless below 2500-3000 rpm? If so you may want to change oxygen sensors, I did numerous things to my truck over the last two years but without a doubt the new o2 sensor did more for performance and mileage than anything else I have tried. (performance great, mileage is up +10% overall in fact highway mileage is about 18.5 again) The truck pulls harder now with the 33's, 3.55 gears, 4.0, ax-15 and 4wd than it ever did as 2wd with the 215 70 tires. I don't like to abuse the drivetrain but it can break the right rear tire loose if I want it too and my buddy with the 94 chev 5.7 litre 2wd is pissed because I can keep up with him dead even now. So I can't wait till I swap to 4.10's. Link to comment Share on other sites More sharing options...
jackel18 Posted October 19, 2007 Author Share Posted October 19, 2007 I think its time to look at your 4.0 and not your gears, does your engine feel lifeless below 2500-3000 rpm? If so you may want to change oxygen sensors, I did numerous things to my truck over the last two years but without a doubt the new o2 sensor did more for performance and mileage than anything else I have tried. (performance great, mileage is up +10% overall in fact highway mileage is about 18.5 again) The truck pulls harder now with the 33's, 3.55 gears, 4.0, ax-15 and 4wd than it ever did as 2wd with the 215 70 tires. I don't like to abuse the drivetrain but it can break the right rear tire loose if I want it too and my buddy with the 94 chev 5.7 litre 2wd is pissed because I can keep up with him dead even now. So I can't wait till I swap to 4.10's. i have a new o2 sensor and I don't belive there is anything wrong with my 4.0. it only has 102xxx on the clock, and last time i checked it helped out to re gear, so all i'm asking is who is running what setup and how they like it. Link to comment Share on other sites More sharing options...
Pete M Posted October 19, 2007 Share Posted October 19, 2007 My 90 has a 4.0/AX-15 with 31" tires and I had a 3.55 Dana 44 sitting in the garage so I found a matching 3.55 front and went with it. 3.55s should be close enough to work just fine. Truck still needs a floor so I haven't exactly done any road testing yet. :roll: But back in the day (when it was just a lowly 2wd) my 88 had 30s with 3.07s and it sucked, then I swapped in the 3.55 Dana 44 and the truck drove great. :D Link to comment Share on other sites More sharing options...
carnuck Posted October 19, 2007 Share Posted October 19, 2007 howzabout a clogged cat? Mine went from 70 to 15 mph when mine finally died. Link to comment Share on other sites More sharing options...
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