Anybody gone to a we shall say 3.23 gear vs the 3.73's that are in your trucks? I was just wondering with as much tq as the truck has would it really have a harder time with the 3.23's I did a search but didn't come back with much so just curious. I tow only a few times a year really and loads stay under 14,000. With PCM re-cal for the gear change would anyone else see anything wrong with doing a more highway friendly gear?

Truck is completely stock and has 31,524 miles on it.

Thanks in advanced
Jason

I thought of doing the same thing for better highway millage. I thought my truck has 4.10 gears and want to go to 3.73. Has anybody know anything about this??????

Your truck should have 3.73's I think but yeah I would like to know if there is a different ratio other than up into the 4.xx range I wanna go the other way haha.

You can do that cheaply by adding taller tires. If you are worried about the power change and just want to see what it would be like, take a ride in a truck with taller tires. the 255/85/16's might be a good option if you are also worried about fuel mileage. If you aren't going to be doing the gear swap yourself, expect about $750 an axle. You'll have to save a bunch of gas to pay for that.

An axle gear change could also mess up the ABS system if the ratio is too far from stock.

You can do that cheaply by adding taller tires. If you are worried about the power change and just want to see what it would be like, take a ride in a truck with taller tires. the 255/85/16's might be a good option if you are also worried about fuel mileage. If you aren't going to be doing the gear swap yourself, expect about $750 an axle. You'll have to save a bunch of gas to pay for that.

I am not too worried about the cost of the work as a friend works at a diff shop and will do it for really cheap.


Can the abs not be re-calibrated with a Tech-2 or HP Tuners on these trucks sorry kind of a noob when it comes to trucks.

An axle gear change could also mess up the ABS system if the ratio is too far from stock.

Could someone explain how changing tires or gears will affect ABS. The only time ABS ever gets invoked is if the rearend is locked up and you are still moving forward. Gears or taller tires should make no difference.

For example you have 295R75-16. That tire is about 3 inches taller than stock. If you have 3.73 rear gears that tire will be the same as putting 3:43 gears in and keeping the tires stock.

Would the change of tires reduce the towing ability though or is D range for the load ok? For instance like in that tire size the BFG Grabber would that be a different load range than the stockers. Sorry for the Noob questions but since this would be my first D Max I have some questions.

As long as you don't exceed the load range of the tires or the truck you are ok.

As for gearing, I think the ABS is only a problem when your final ratio is above the stock setting by too much. For example, the 37's with 4.56's gives a final ratio of about ~3.76 which is borderline too much above the 3.73. If you gear lower then the ABS never thinks the wheels are spinning too fast because the wheels go around fewer times per revolution (i.e. slower for a given speed or rpm).

Could someone explain how changing tires or gears will affect ABS. The only time ABS ever gets invoked is if the rearend is locked up and you are still moving forward. Gears or taller tires should make no difference.

For example you have 295R75-16. That tire is about 3 inches taller than stock. If you have 3.73 rear gears that tire will be the same as putting 3:43 gears in and keeping the tires stock.

The ABS system works by comparing the speed that the various wheels are turning while the brakes are applied. The front wheels each have a sensor mounted in the hub. The rear wheels have no sensors, the speed for the rear axle comes from the speedometer pickup on the rear of the transfer case. With stock 3.73 gearing, under normal braking conditions in a straight line, the ABS computer would expect to see 3.73 revolutions of the rear output shaft for each revolution of the front wheels. There has to be a window around this number of course to compensate for braking while turning, which would have the front wheels traveling a further distance than the rears. If you change gear ratios in the axles, the normal 3.73:1 ratio is no longer valid. The further the new ratio is from stock the more likely it will cause an ABS issue. Changing tire sizes alone shouln't cause an issue with the ABS since the normal 3.73:1 ratio of rear to front speeds is still valid.

Good info thanks guys.

Have you found a 3.23 gear set for the AAM 11.5? I didn' know anyone made one? Lowest comercially available is the 3.73. I have seen that AAM makes a lower (numerically) gear ratio, but won't sell it to the general public.

You can get a 3.55 ratio now. I would like to see a 3.23 ratio.

After running stock gearing and 285's for a while now, it seems like I saw only about a 1mpg improvement when cruising unloaded on the highway. And I saw 2-2.5mpg hurt when towing heavy.

I don't know if the cost of regearing would ever be re-couped from any improved economy when unloaded.

I'm strongly considering returning to 265's for towing/working. THe problem is they look goofy on the truck with the green-key lift done to fit the 285's.

--Rob

I have not found a 3.23 gear yet :( I did see the 3.55 but I am holding out for a 3.23 or 3.42 maybe