I was debating on posting this in the Superduty section, but thought better about it. I'd like to get the opinion of the V10 guys. I have a 02 F350 with 4 inches of lift. I'm runnin 315/70/17 BFG's. (Basicly 35" tires) The 3.73 gears in my truck make's it feel like a slug, So i think i'm gonna bite the bullet and get some new gears but i'm so undecided on the ratio. I've read a bunch of posts and now i'm even more confused. (Yes I know how they work and why, I'm just scared of dropping a bunch of money and not being happy with it.) I was thinking of going to the 4.30 gears, then again why not the 4.56? Or even the 4.88's... I was thinking of getting some 37'' tires when these ones wear out. So I need some input! And does anyone know a good online site for gears? I'm more than capable of installing them myself. I tried a parts store up here in canada and they wanted 500 for the gears and a mini install kit. I thought that was kinda pricey!

 

4.88's especially if you're thinking of going 37's in the future.

www.ringpinion.com is one of the better known sites.

 

Ken is dead-on. Go w/ the 4.88's. You'll be happier in the long run. Heck, I've got 4.30's now w/ 285's and I'm thinkin about 4.88's. If I was running 37's, I'd probably look into 5.14's or 5.38's. Good luck.

Dave

 

Get what ever gear set that relates to the tire diameter you will end up with and puts your 70 MPH cruise speed in the 2000-2250 RPM range

There are tons of calculator out ther for this just use google

the OD final trans ratio is 0.71:1

 

This one has always been my favorite.
http://www.angelfire.com/space/slr/RPMCalculator.htm

4.88s and 35's would be similar (even a bit deeper) than stock tires with 4.30's...and you how everyone here raves about 4.30s!

 

Thanks Monsta, bet I loose this link too

one of the better ones cuze playing what if works instantly

70 MPH 37" with 4.88 and 0.71 final give 2204+- RPM right in the sweet spot

 

Thanks guys! 4.88's it is!!! My trucks now not only sweet, she's gonna be a damn race car! Well, not quite... but I love my truck anyways. lol

 

Let us know how the install turns out. I am curious how the 4.88's are.

 

I went from 4.30's to 5.13's after I bought a 34' toyhauler.I already had 38" tires,so I needed the 5.13's to get me in the torque sweet spot when towing.Especially pulling big grades.Hauls @ss without the trailer hooked up!

 

Hi - dmilkman (I like that name!)


Tell all the guys here how you get 16 MPG also


Read your PM before responding


OK OK just being a tad sarcastic folks don't have a cow

 

dmilkman,

That's what I'm talkin about!!! Guy's w/ 3.73's and BIG tires that don't understand why their V10's are sluggish???? Are you reading this???

 

Don't mean to hijack Bracen

I know I'm not gonna get great mileage out of a V10.Especially w/38's or pulling a trailer.I just gas up when needed,who cares We didn't buy these trucks for mpg,we bought them for power without the cost and upkeep of a diesel....Right guys

Fredvon4-
I imagine that I get around 9-11 mpg unhooked and 7-9 hooked up.I never got the speedo/odometer re-calibrated for the 38's so I can just estimate.

 

yikes. i'll bet that auto trans dosn't shift correctly.

 

Charlie

I helped a guy back a few years with a botched Fabtech 8" and traxus Mudders in the 38 x 16.5 range

On my recommendation he had 5:12s, air lockers, custom full articulating drive shafts, long (I mean real long) torque bars on the rear axle, basically a 4 link system designed by me, I did the install and tune for the Nos system. Frank has a lot of money and had a hard head with a very hot PSD to respond to.

During the testing, we ultimately broke the 4R100 and the transfer case.. but I have to say, before we broke it, the 4R100 (I drove it several times) behaved and shifted normally in spite of the added torque load... remember the lower gears and the higher diameter tires makes the engine RPM to speed (MPH) ratio about the same as stock... only real difference is the feedback torque load

This truck is the 01 I had the most experience with. Most of the mods are similar to what you went through with the 05 except the programers of the day were not as sophisticated as the one you got to play with.

It was a 2 door 01 F250 LB 4x4 ESOF. He ran it several times at Little River 1/8th and was busting into the 12s (corrected 1/4 mile) fairly consistently. For the drag races I convinced him to slap on Dick Cepec 32x13.5s and run 4x4High

I also helped with a very high lifted Excursion that was PSD into a 4R100 and it too (once bulletproofed by Brian) behaved surprisingly well for street driving.

I think dmilkman probably does not having any shift problems.... but I hope, if his 4R100 is stock, that he considers one of the re-builders out there that can "bulletproof" it. There are several areas with Ford original parts inside that are light weight crap and not very durable for high torque application

 

It shifts perfectly,no complaints.I've been driving/towing with it that way since 2002.I also installed a second larger tranny cooler in line in front of the radiator to help the stock tranny live as long as possible.