bighouts5591

I've heard it mentioned that if you have oversized tires and stock gearing its better to drive in 3 on the highway over D because it will put you in the right range to lock the torque converter and you will get much better gas mileage. I'm running 33s on stock 3.55s, any thoughts on this?

kennzz05

pretty sure the torque converter wont lock in 3rd what are your rpms like at 70 in D and 3RD

bighouts5591

I know in D at about 60-65 they're around 1800. I'll have to check on what they are in 3. I never go over 65 in it to be honest, she's a trail rig and the only time it sees the highway is to get to places to wheel

kennzz05

1800 is pretty low u might do better in 3rd id think 18 would be pretty much bogging it down

bighouts5591

I'll have to try it, only problem is my speedo is off so I can't track my mileage anyways. I'm probably just going to start trailering it anywhere over like 30 miles

Lowrange2

Sooo, why don't you regear and put the right speedo gear in it?

I would suggest that you not drive it like that. You'll be replacing transmissions if you drive it often.


Que "I drive on 2.73s with 40's all the time." statements.

bighouts5591

I don't see any point in regearing it at this point. I still have plenty of torque and power and I don't plan on going any bigger tire-wise. I'd rather spend my money on something more useful like lockers or armor. And as for the speedo gear its only 5 MPH off I just can't accurately gauge my mileage, which I don't care about, because my mileage is exempt on my title and I know how often to change my oil.

Lowrange2

Ok.

I hope you never tow anything.

holycaveman

Its pretty simple really. If its constantly kicking into passing gear to keep your speed, then just run it in third. Rpms do NOT hurt the motor. But constantly kicking in and out of gear is hard on your converter and transmission.

With my 32's I do this. Pick a normal cruizing speed during normal conditions in od. Holding at that speed manually shift it down to third. If you go faster by shifting it down then you're straining the od. If you stay the same or slow down then overdrive is fine.

bighouts5591

No sir, that would be what the truck in my signature is for. The XJ doesn't tow that well stock, I wouldn't be dumb enough to tow with oversized tires.

Gee oh Dee

The torque converter locks in 3rd and 4th iirc....


So you'll send cash on lockers but your not gonna regear? Seems backwards...but to each his own. If you want to ignore the advice of the experienced, intelligent folks out there go right ahead.

zimdogg

What's wrong with towing and having oversized tires? I tow my boat regularly on 32's. My Jeep has 170,xxx miles on it. My Jeep didn't even come with the tow package, and I was even lucky enough to get stuck with the D35. I still have stock gears in, and have not had a single issue yet, even while towing when ambient temps are in the triple digits during this heat wave we've had in the midwest.

Granted, since I know I don't have a tranny cooler, I don't even run the Jeep in Drive as an effort to keep the TC from burning the transmission out. It's not a rocket going uphill by any means, but it gets the job done.

zimdogg

TC does not lock up while in 3.

xj_maniac_newb

if your on 33's you should be more than 5mph off.. On 31s im goin 60 when the speedo reads 55..

You should be somewhere in the range of 9-10mph off. So when your speedo reads 55 you should be going 64.8 if my redneck math is right.

zimdogg

It's just a percentage. The speedo will be off x% through the entire RPM range. It's not a constant MPH that the speedo is off.