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3.73 vs 4.10

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Can anyone shed some light on what you would expect the rpm increase would be at 65mph when swapping out 3.73's for some 4.10's. I've towed trailers over 10k on some decent hills with the 3.73's and it did well but I'm curious how much better 4.10's would do. Obviously there is some mechanical advantage in play but how much of a difference would I see.Thanks guys. Love this Forum

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169 RPM increase with those tires and 47RE in O.D.

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Wow, thanks. I didn't expect an exact number like that. So what will that do for towing. My wife and I are looking to purchase a travel trailer this September. Its roughly 11k. Is it going to help the truck noticeably or is it not worth the upgrade. I guess what I'm looking to do is add a little peace of mind knowing that I'm not killing my truck to bad when I hit the mountains. I came across the link below that shows a 2k# towing increase between the two gears. Does that sound right? http://dodgeram.info/2003/load-tow/2500.html

At any given speed the mechanical advantage is 10%, not to mention the hp increase from 10% higher rpms.

I think you would like it with those tires, but hard to say if you will like it enough to justify the cost.. Really unless your doing 70 in OD you don't have the rpm's with either gear set to pull too many hills with a locked tq converter, so 3rd is your hill pulling gear for anything big and in 3rd at 55 you should have the power with 3.73's, but 4.10's will be quite a bit more if you find you are lacking. I wouldn't spend money on it yet, tow first.

Some examples,

65mph, 4th gear with 3.73's is approx 1748 rpms.

65mph, 4th gear with 4.10's is approx 1922 rpms.

65mph, 3rd gear with 3.73's is approx 2534 rpms.

65mph, 3rd gear with 4.10's is approx 2785 rpms.

55 mph, 4th gear with 3.73's is approx 1479 rpms.

55 mph, 4th gear with 4.10's is approx 1626 rpms.

55 mph, 3rd gear with 3.73's is approx 2144 rpms.

55 mph, 3rd gear with 4.10's is approx 2356 rpms.

45 mph, 2nd gear with 3.73's is approx 2543 rpms.

45 mph, 2nd gear with 4.10's is approx 2796 rpms.

35 mph, 2nd gear with 3.73's is approx 1978 rpms.

35 mph, 2nd gear with 4.10's is approx 2174 rpms.

--- Update to the previous post...

You money would probably be better spent on a tq converter, valve body, and a Smarty Jr to make your truck a HO. And get rid of the K&N crap!

I have 4.10s but am only running stock rubber. The truck is not happy at highway speeds unless I tow in OD which is NOT recommended. I'm not about to change axles but if I was doing it again, I'd go for different ratio. I think you'll be happy towing with 3.73s without OD engaged.

I have pulled my 38 FT fifth wheel all over and I have NOT had any lack of power. You can see what I have by looking at the botton.

I would never switch to, or order with, or choose 4.10s with stock or mildly larger tires.If you're towing 20k, maybe.If you're going to be running 35"+ tires AND towing, yes.If you want to run 40" tires, sure.Otherwise no way, no how. I hate my 4.10s.

When towing in 6th I wish I had 4.10's, when in 5th I wish I had 3.42's.. guess 3.73's are good for me!It comes down to what speed and gear you plan to be in. If you want to pull 11K in OD, which is fine with a few trans upgrades, then 4.10's are better. If your just going to slow down and run 3rd then 3.73's are better, trans upgrades and hp upgrades are still good.

  • 2 weeks later...

I have been all over the west on some very steep pulls and have never had any trouble for power.The jake brake has saved my brakes. I would never owen a truck that did not have the JAKE or one close to it.33.000

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