Anybody running with there overdrive off? With the new tires (33")I'm running1800 RPM @ 70 MPH. In North GA that dosent cut it. With OD off I'm running 2900 RPM, it's a little high but it dosent down shift every other minute. Will this be bad on the tranny untill I can get it regeared?

Been doing it for two years with 35's. Lots of people are doing this with out a problem

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ya but your mpg goes to shit

I run 3000rpms in OD with 35's and 5.13's @ 71mph.

You'll live.

programmer will help out alot...since your only running 33's id suggest that over re-gearing...it will put you speedometer back to where it needs to be as well as correct the shift points if your an auto..and make it much more pleasant to drive...if you plan on going 35's or bigger id get it re-geared

My mpg is better running with out OD on the highway. I assume it's because it doesnt rev to 5k rpm every other minute. (35's 3.73s)


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I've been doing it with 35s as well. Think it is easier on the trans to not constantly shift up and down

OD off is better for your trans and brakes...not so good for your wallet at the pump.

I run 35s and 3.73 17mpg with OD on, 14mpg with OD off.. and this is not flat ground, but not mountains like Colorado either. I suggest you run 1 tank of gas with OD off. then 1 tank with OD on. Do the calculations and see which works best for you in your area with your driving style. I think the issue may be if you're running OD off and your engine runs a constant 3000rpm you may very well overheat your transmission.

Tranny coolers really are not that expensive.... i dont have one.... yet and my fluid is still fine w/45k miles.
I turn od off only when pulling trailer/ up and down hills alot or long up hill to limit shifting.
I tried it off on one trip and noticed at least 3mpg diff. running 35 heavy ass toyos and 410gears also with procal recalibrated

I get 13 around town with it on and 14 on the highway lol. Heavy 15" mtr/k lol. The only time I turn it off is on the highway above 75.


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Thanks for the input. I'll look into a programer short term then think about gears next tire change. Next will be 35's

The high RPMs are not what generate heat in a transmission. Its the constant shifting and tranny running without the TC locked up.

If your tranny is hunting at freeway speeds, take it out of OD. If you keep it in D in an attempt to get better MPG, you will soon be spending those savings on a smoked tranny. It wont hurt the engine to run around 3000 rpm.

Re gear, add a cooler etc. During the summer, with an add on tranny cooler mine will still get up around 160 degrees running on the highway.

i run with od off. 35s and 3.73s also have a bm tranny cooler.

I run this way also only thing I can say to it is offroad sux...your gearing is all wrong when your trying to crawl..other than that it's more than manageable for me on hwy

i would go out and get you an aev procal to somewhat help with your shifting points. it's cosst effective and not as high as other programmers. i have been running with my od off for over a year with stock gears and my 35's, but once i hit the interstate at about 75 i will turn it on.

Yup Procal if it's a stick programmer if your an auto

Not always. High RPMs don't always equal bad MPGs. If you are constantly driving at 1800 RPMs then you will find youself on the gas pedal more often than you will at even 2800 RPMs. Before I got new tires after my regear I would see 23-24 on the highway doing 65 (though going much faster drove you insane with the engine drone). And yes, I did my own calculations for MPGs.

This is just a result of not constantly having your foot on the gas pedal.

Once the new tires came around I dropped back to reality with the added weight and lower RPMs.

I've ran 1200 miles to Moab twice with OD off running 3500-3800 rpms all the way on the interstate with no problems at all....Tranny fluid still looks good. I have 35" tires and 5.13 gears....This motor will take a beating and the tranny will run cooler not shifting in and out of OD...

I have been doing it for 60k of the 80k on my 2 door with 37s and 3.73s. Average about 16 to 16.5 mpg driving 75. Any faster and it drops to 12. Fluid still looks new.

Good to know it can be done. Thanks for all the input

Seems a little high to me, but hey it's your JK. I feel like I'm pushing it at 3k for extended periods.