I bought my '03 F350 with 3.73's, kind of a mistake, but it was the one on the lot, and I wanted it RIGHT NOW!!! lol, oh well!

I have since lifted it 8", and have set of 37" MTR's on it. I was debating between the 4.30's and 4.56's at first. However, after talking to several local shops, and friends, I decided to go with 4.88's.

Apparently there are no 4.56 ring and pinions made for the sterling 10.5 diff. The 4.56 is only made for the 10.25, which you can install into the 10.5, but you have to buy the install kit for approx. $150 more. That's not a big deal if you have higher milage on your truck, but I only have 10K, so I don't need to replace all the bearings, and would prefer to keep the 10.5" ring gear. I'm getting Superior Gear 4.88s installed for a total of $1238.00 (after tax).

The RPM difference between the 4.56 and 4.88 gears at highway speeds is minimal compared to the performance gained. Not to mention the reduction in wear of the transmission when driving around town, (and supposed gas milage increase in stop and go conditions).

The differences are:
@70 MPH
stock tires & 3.73s = 1914 RPM
37's and 3.73s = 1707 RPM (bad)
37's and 4.56s = 2087 RPM
37's and 4.88s = 2234 RPM

@75 MPH
stock tires & 3.73s = 2051 RPM
37's and 3.73s = 1829 RPM (bad)
37's and 4.56s = 2236 RPM
37's and 4.88s = 2393 RPM

I don't know if this will help anyone, but thought I would throw it out there. A small RPM difference seems well worth it to have the power available to me, and to save wear on the tranny, etc.

Just my .02!

 

If you are changing gears, you're going to lose your existing ring gear anyways, as the new ratio will have different ring and pinion gears. My Reider Racing catalog lists a 4.56 ratio gearset for the 10.50" axle. There is no carrier break on the 10.25"/10.50" axles.

I have 4.56 Precision Gears in my 10.25". I'm running them with 33" tires (originally had 3.55 gears and they were way too high for a truck this heavy with a 351, even with stock tires). If you have a gas engine, 4.88's will be good with 37's. If you have the diesel you can get away with 4.56's. Your plan of going low on the ratio is a good one, can never have too much power, and since you have overdrive, you're good to go.

That's a descent price on the gear change, my gear change was $1650 + tax for both axles, with a Powertrax LockRight for the rear accounting for $325 of that. I used Dana Spicer gears in the front and Precision Gears in the rear. The Precisions were about $85 more than the Superiors.

Have fun with the new gears, you're going to love the difference in power! If you don't already have a locker or limited slip, now is a great time to put one in. I like my LockRight alot.

 

I got 4.56's for my 10.5 from Precison Gear...i dont know if id trust a shop that said any differnt.. i run 36"s with 4.56s with V10... if i had it to do over id go 4.88s.. with 37s youll be perfect... unless you have a diesel... than that might be too much gear....there redline is low..

 

If you have a psd I would do the 4:56's. LOTS of compnaies make them. Reider Racing, Randys, U.S. Gear. Those 4:88s may be too much, especially if you have any power mods.

 

I'm going to have to do a little more research. The guy I talked to said that the 4.56's fit, but that it's actually a 10.25 ring gear, I dunno. Either way, I still plan on going with the 4.88's since I do have the V10, without any mods (so far).

As far as the shop's reputation is concerned, it's Drivetrain Direct in Corona, CA. So far I've never heard anything bad about their work, just positive things. So unless I hear something bad in the next day or so, I'm prob going to keep the appointment. Luckily the salesman on the phone isn't the one doing the install!! lol

Thanks for the input guys, always appreciated. Helped me decide what lift to buy, gears to go with, etc.

 

What are you going to pay?

 

$1238 after tax. Everyone else in the area wanted $1400 + tax.

 

That's a good price.

 

Yeah, I was kinda suprised when he told me the price. Everyone I asked about that place said they were good, but a little high on the prices. Turns out that they must have heard that rumor, and lowered the prices!

CWB...what gears do you run in yours?

 

Anyone have any input on the quality of Superior Gears?

 

I have Yukon's from Randy's ring and pinion. I think I paid about that but a buddy did it. Plus I put in two arb's so that raised the price a little.

 

CWB..what ratio and tire size do you have?

 

4.56's with 40"s.Wish I had 4.88's.

 

After much research, I have heard only good things about Precision, Yukon, Richmond and Superior Gears. I am sure there are others also.

 

I ran Superior 4.56's with my 36" PJ's and had no problems. Needed to go lower when I went to 39" Mickey's so I went with 5.13 gears... also Superiors.
They seem perfect for the 39's!