to use overdrive, or not too??

I have read alot of posts saying not to use overdrive and you will get better mileage. I have a 91' with the AW4 and its lifted with 33x12.5's and 4.56 gears. should i just be using 3rd all the time??? even on the highway?? cause i noticed that on the highway going 65 with these gears and tires iam revving around 2100rpm which seems a little low.:dunno:

I think most of those posts were for guys still running 3.55 stock gears with larger tires. 2100 in OD sounds good to me! Pretty close to stock rpm's IIRC. :cheers:

300$XJ said:

I think most of those posts were for guys still running 3.55 stock gears with larger tires. 2100 in OD sounds good to me! Pretty close to stock rpm's IIRC. :cheers:

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X2 I would drive in OD you are setup pretty good right now

what about an '89 with stock gears and a 3" lift with 31" tires?

Muddy Beast said:

what about an '89 with stock gears and a 3" lift with 31" tires?

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i keep mine in OD at all times when im running 31's

is your speedo correct? I run mine in 3rd at 3k and about 80??(about) thats with 3.55s and 33s

i thought i would get better gas mileage with these gears and tires!!! i'm getting like 14mpg..... maybe plugs, wires, a cap, rotor and oxygen sensor will help??? hopefully

If you change tires without changing the speedometer gear in the transfer case(tail shaft housing on a 2wd) your speedo. will be wrong. The dash instruments will show the same RPM at a given speed, but the speed will be wrong. Swapping gears (with the tires or later) will require another correction. Without correcting the speedometer, your odometer read will be wrong, highway speed wrong, MPG figures wrong

Just ran across this on another thread. It's a speedometer gear chart for R/P and tire swaps
http://www.rock-itman.com/custom/speedometer_gear_chart.html

Might help for those of you wanting to correct your speedo.

Do the mile marker check(drive 10 miles on the highway between mile markers, then compare it to how many miles your odometer registered) and you will have a "correction factor" to figure out how many mile the jeep is actually traveling, then you can at least figure out actual MPG.

i have an 00 cherokee 4.5'' lift and 31's in drive i was gettin close to 15 freeway, and i tried my same daily drive in 3rd and got close to 18
i still have more testing to do though

Best way to find out. Just try it both ways and see which one gives better mileage.

Cheers to the Genius!:sunshine: