Hey guys,

Love my '11 f250 SD 4WD CC SB. 6.2 with 3.73 e-locker. I've got 5 Star tunes in it, and the truck is a joy to drive empty, and tows my current 7k camper fine, though on steep inclines I wish I had the 4:30 gears.

Well, we just bought a bigger trailer, dry weight is an addtl 2400+ at 9400, so I'll need to do something.

I don't want a different truck, don't want (another trouble-prone) diesel. I think with 4:30s and the tune, I should be fine towing that trailer (with gear and passengers, probably 11-11.5k loaded). Not doing mountains here, just Michigan hills.

What's the best way to "do" a gear swap? I know if I buy a set of gears and a shop screws Em up, it's gonna whine/hum and still cost 2k to do (truck is 4wd)
I'm up in the boonies and finding a shop to swap the gears will be a problem. Getting Em done right will be even MORE trouble.


Can I just find 4:30 axles ans have them swapped (anything in t-case or sensors need to be touched?). I don't care if I lose the e-locker, I never use it.

Thanks for insight!

 

Any idea where I can FIND 4:30 axles at a decent price would be appreciated, too.

 

Do you need lower than your current 1st gear with your 3.73 rear?

If the issue is not taking off from a stop, the 4.30 rear is no difference then running on one gear lower with a 3.73.

i.e. ...you might climb a step grade in 3rd with a 4.30 and with a 3.73 you would be in 2nd. etc.. In the end its overall gearing.

Now! from a dead stop I know it is different. But after 1st gear its not much, if any, difference.

I see you have 9400lb trailer, I really don't think you will see any difference.

 

You won't notice a difference from the weight. The bigger issue is aero drag and that won't change much, weight (within reason) is not that big of a deal. I wouldn't change axles personally, I've done it that way before and the cost of putting all new brakes and such on, plus the cost of the axles, would have paid for the gears a couple of times over. Plus axles are coming out of a truck for a reason, mostly that the truck is trash because it's done a million miles or got totalled - both reasons to stay away.

 

Excellent info, thanks guys!

The off the line power is really lacking with the new trailer. Once up to speed, it's not as bad. Aero drag is huge right now, perhaps a deflector would help a bit. And, I could jump back to a 93 tune for towing and see if the extra 15ish hp/tq helps.

 

you would love the 430 gears,it makes it easier on the truck. 373 is a good all around gear, my 1998 v 10 had it.
but if i was you i would get rid of tuner, i tried one of thoseand it messed up my transmission one of my trucks. what happened it messed up shifting solinoids and i had to have new solinoid pack installed which cost $600.00. the tech told me those tuners will mess up a factory system over time. i never modify anything just do main and drive normal and the rest will take care. ring and pinion swap for 430 will cost about 2k, make sure u get somebody that is well know for ring and pinion sawp

 

Over all you maybe just as well to leave well enough alone. The cost to convert, then toss in a slight lowering of everyday MPG vs. the frustration of not reaching the top of the hill a little quicker may not be worth it in the long haul.

Your RVing, your supposed to slow down and enjoy the journey as well as the camping.

 

X2. I would stick with the 3.73 and just downshift going up the hills.

 

^^THIS

I've never understood the need to be the first guy to the top of the hill. It's supposed to be a vacation, not a race.

FWIW, my vote would be to leave the gears alone. I think you'll end up really ticked off after you spend all that money, time and effort swapping gears and see almost no improvement at all.

Just my 2 cents worth, and you'll have over paid at that. Bottom line is it's your truck, and you're the one that needs to be happy with it. So do what makes you happy.

 

I have the same set up as you, but with out the 5 star tuner. Last February I pulled my 6 ton flatbed trailer with my JEEP and my Polaris Ranger on it, which was pretty close to your 9000 lb weight, west on I-90 to Butte, MT; then south on I-15 to Las Vegas area and returned two weeks later with the same load and my 6.2 with the 3.73 gears had absolutely no trouble pulling any of the passes or hills on that route. For 2 of the driving days, I was also pushing 35 to 45 MPH head winds!! I just had to switch the instant fuel mileage indicator to some other gauge because I couldn't stand to watch it!! Haha!
But still the overall average fuel mileage for the trip ( Just short of 3000 mi.)
was right at 9.0 MPG by the lie-o-meter. Which I didn't think was too bad!
Good luck. And from gear changes I have done in other vehicles, I don't think going from 3.73 to 4.30 is going to make enough difference to warrant the work involved. On my JEEP, I went from 4.10's to 5.38's and was kind of disappointed at how little difference it made.
Good luck.

 

Except that when you shift to the next gear it will be "closer". I.e going from top of first to second gear wit 4.3 the rpm wont drop as low as with 3.73. With his gvw may not matter but that is the big advantage of kower gears. Alot of situations where you are stuc in 1st becuase it bogs in 2nd a lower ratio will let you get in 2nd and keep accelrating

 

3/73 to 4.30 swap has no effect on MPG, on my 2004 F350 when i did this swap i lost nothing in MPG but gained daily driving and towing ability. Go to the 6.2 section and see ALL the MPG threads between 3.73 and 4.30 there is ZERO difference. The 4.30 gears will build rpm quicker for towing them loads and have th ability to hold a gear better because of the added ratio on long uphills. And when it shifts up gears the added ratio from 4.30 will keep the rpm higher though the shift AGAIN not lugging the motor. Doing the 4.30 swap on my older 2valve 54 was hands down the one ad only hing that helped period, i actually wished i installed 4.56 gears with the 285/75r16 tires i run to get more grunt and pulling power,and highway rpm would only be 300rpm more. So instead of 2000rpm at 70mph it would be 2300rpm at 70mph unloaded towing, no way you should be going over the speed limit with 9 plus thousand pounds behind you

 

here is the youtube video of a member on here with his 2011 F350 with 6.2/4.30 geared truck AND running 35" tires....... no 3.73 geared 6.2 would pull like this!

 

That particular run was when the truck was bone stock (no tuner, stock tires).

The latest Ohio meet was the first time I'd pulled at that event with the 35" tires (running a 93 5 star tune). Trailer was just over 15k the last time around (15,100) and about 200lbs lighter (15,300) than the video SDS posted above.

 

The 5 Star custom tune will not destroy your transmission. You will love your 4.30 gears, towing or not.

Randy's Ring and Pinion is a good source for parts, if you are doing the swap yourself. If you need a recommendation of a local shop for the work, stop and talk to your local 4x4 shop. They will know where you should take your truck.