New Truck Order Questions (Rear Ratio) - Diesel Forum

Road Racer · 10-13-2001, 08:46 PM

I went to 3 dealers today with the intention of ordering a 2002 F-350 Super Duty, V-10, CC, SB, Auto, 3.73.

Only one dealer had a V-10 equipped truck (one dealer had 40 Power Strokes and not a single V-10) that I drove a few miles simply because I had never driven a V-10 powered Super Duty.

The truck I drove had the 3.73 rear. I drove it a couple of miles with the OD turned off as I am not sure if a 3.73 Auto V-10 will pull my enclosed trailer (7,000 lbs) in OD.

The revs at 65-70 MPH were not a big surprise but the V-10 sounded "busy". Two questions:

Do I need the 4.30 to tow my trailer?

If I order the 4.30 and find the ratio too short for non-towing what would be involved in changing tire sizes to adjust the actual rear ratio? Are "E" load rating tires available in a size that would change the ratio to something around 4.10? Would that change require the purchase of new wheels?

Thanks for any advice.

-rod

sloans4x4 · 10-13-2001, 10:08 PM

Get the 4:30s and I'll just swap you for my 4:10s!! [img]images/icons/laugh.gif[/img] [img]images/icons/wink.gif[/img]

Troutly · 10-14-2001, 01:53 AM

Order the 4.30's . I think you'll see the difference in towing, with little difference in fuel mileage.

I can't exactly answer the tire/gear ratio question, other than a larger diameter tire will get that ratio below 4.30 .

Don't be overly concerned with the "E" rating. Look at the actual tire load capacity. You will find some "D" range tires out there with capacity very close to our "E" range.

[img]graemlins/smokin.gif[/img] [img]graemlins/smokin.gif[/img]

dan4x4 · 10-14-2001, 10:49 AM

Get the 4.30s. I have the 3.73s and do not tow as much as you will, and I really wish I had the lower gears.

Dan

Mark Kovalsky · 10-14-2001, 06:29 PM

I have 3.73 V10 with a manual and tow 9,000 lbs in overdrive. My previous truck was an E350 V10 auto with 3.73 ratio and pulled the same trailer just fine in overdrive.

SpOOk · 10-14-2001, 07:14 PM

With the advice form several members here, I contacted my Dealer to "hopefully" change my original selection of the 3:73's to the 4:30's.

I already have the VIN number and he said that it would be a 50/50 shot to get them... I am hoping the change makes it through. [img]graemlins/shrug.gif[/img] [img]graemlins/vulnerable.gif[/img]

Road Racer · 11-02-2001, 11:25 AM

Thanks for the opinions. It may seem that I am taking the advice of the minority but I ordered the truck with the 3.73 LS. I was leaning toward the 4.30 but a friend/mechanic who owns a small garage insists that towing in O/D will shorten the life of the auto trans.

-rod

NoMo · 11-02-2001, 11:50 AM

It'll be OK- that's about what my 5th-wheel weighs. I just can't tow in OD a lot.