4:10 or 3:73

[icanfixall]

As some of you know about my rig. I tow lots. I run a set of stock 3:55 gears and the Gear Vendors Splitter., With my BTS E4OD that gives me 8 forward gears to choose from and I use them well. Its kinda exciting to shift 8 times when getting up to freeway speeds. I don't really need to use all those gears but its still fun... So I have been trying to make a gear change but don't know how far to go. I can pull well enough with the 3
;55 but it does put a strain on the truck too. The 4:10 gears will be almost too easy to use and I kinda like that. Clearly the finall gear ratio in double overdrive will drop useing any of the two choices I am looking at. So I'm asking what you guys would do with the gears. 4:10 or 3:73... I'm listening for reasons why you would choose either.. Thanks all...

 

[Dsl_Dog_Treat]

Gary, you'll miss the 3:55's for fuel sipping.
Mater my plow truck is running 3:73's with a T-19 and does everything I need but long highway runs.
Goldie's 4:10's and the heavy fiver I pull (11k empty) I feel is geared right for pulling and highway and isn't too shabby on the fuel.
would I put the 3:73's in Goldie as a heavy hauler. Prolly not. Just my humble opinion.

 

[justinray]

If it's possible with 3.55's, then I wouldn't want to go to 4.10's, too much gear for the application, if I was to get a gv unit, I would likely go to 3:55's. also, if I ran these numbers right, it looks like if you could get the truck to 230/450, running 3.55's would feel comparable to the 4.10's on a stock truck, you would be pushing the same power to the wheels, and getting better mileage. Add the GV and you have more pulling power than the stock truck with 4.10's.

 

[FORDF250HDXLT]

if i had a GV unit behind my E40D i would also have my cake and eat it too (the whole reason id install a GV)
id have 4.56-5.13's.keeping in mind,the fastest i drive is 45 mph.sometimes 55 mph.very rarely 65 mph interstate.-and that's just to open her up a bit for fun,for a mile or two.then i slow back to 55 out there again even.im very rarely out on the hwy with the truck anyway though.Maine hwy's are not dangerous like many others.we can go 45 mph in the right lane very safety (lowest allowed by law though) if we want all day long,issue free.
so what would be ideal for some,would be miserable for others.you just need to check out the online calculators and figure out the gearing/rpm charts and pick what would be ideal for your truck,for your personal uses.

 

[icanfixall]

At my current gearing and in double overdrive doing 85mph I'm turning 1800 rpm. I can do that all day long with the power in my engine. Ot untill I come to a grade.. Then the engine wakes from its sleep anmd starts working...

 

[redneckaggie]

All numbers are final drive gear with 235 tires and figuring the gv at .8 high range. first number is 1750 rpms, second is 2000 rpms

Gear 1750 2000
3.55 77 88
3.73 73 84
4.10 67 76

 

[RLDSL]

WELL, I've got a 4.10 rear in mine and I tow like a maniac and Ive got 15 gears to play with , with double OD and personally, when I'm towing, I feel like 4,10 is still too tall. 4.56 sounds a lot more workable really. Running around empty, Im in double over anyway so it would help with the fuel a bunch, granted it all depends on how heavy you get.

 

[dizdak]

if you are running larger than factory tire size by a few sizes i would think the 4.10s would be better choice... reduce the strain on things, get off the line a little easier..

 

[rockbender]

The problem is that going from 3.55 to 3.73 is such a small change, you'll likely only be jumping up 100 RPM at 85, and then another 200 between 3.73 and 4.10's. To me, the 5% change in gearing wouldn't be worth the trouble to go to 3.73's. I think you'll still have the best of both worlds by going to 4.10's. 2100 RPM at 85 shouldn't make a huge difference in economy based upon RPM's alone and should still be tolerable noise wise.

I'm basing my guestimations off of towing in the 65-70 MPH range and running empty in the 80 ish range.

I wish I was running 1800 RPM at 65!

 

[FORDF250HDXLT]

wow some of you guys sure are in an awful hurry.i dunno how you can afford it @ these fuel prices.
have a hatred against keeping some $ in the bank lol?
remember it's not only about rpms.it's the force of the air your cutting through.

 

[GOOSE]

After grossing only 15-16000lbs and traveling to the rally and back last year, I would like to have 4:56's with the GV double overdrive. Right now with 4:10's, I'm running about 2500rpm's@75mph. 3rd gear was common on the hills and one pass took me to 2nd gear. This is with the ZF 5 speed.

I get 14mpg around town all the time. around town in south jersey is doing 45-50mph and stopping every1/2-3miles. I actually got 3mpg better around town at the rally because the stops in Michigan were much farther apart than in NJ. I got over 17mpg over the course of the week, including the 3 dyno runs. I was quite happy with that. Towing average was 9.5-12.5 depending on the severity of the hills I was in.

I think it was Heath that suggested that I just keep the 4:10's and get a GV underdrive set up. That setup would probably suit me best. I know that keeping the rpm's down will help mileage but my truck is 7600lbs, thats a lot of weight to pull with gearing thats best suited for highway stints. There has to be a fine line where steeper gear is as much of a help towards mileage rather than a hindrance.

Gary, I would love to see your setup in a F150. The mileage would be inspiring I would presume. A one ton crew cab that tows frequently, I'd have to want 4:10's at a minimum, the GV would only add confidence to this statement. I hope my numbers and highway experiences may be of help to you. Good luck with your gearing quandary, I am very interested to see how it pans out and how the end result compares to what you have.

Food for thought: a used 4:10 rear would bolt in with only a few hours of wrenching, even if it was for testing purposes.

 

[rockbender]

wow some of you guys sure are in an awful hurry.i dunno how you can afford it @ these fuel prices.

Time is money, right?

In parts of the west coast, you get run over doing less than 65... sometimes more.

 

[SparkandFire]

The only way I would ever run 3.55 gears would be if a six cylinder cummins ever sneaks it's way under the hood of my truck...



I had 3.55 gears on my '87 truck, even with the C6 that thing was really a dog with any load on it.

4.10 gears and an overdrive transmission is the best setup I've found for the IDI truck. I get good fuel mileage, but then again I never, EVER go over 70 mph.

You might need to get a lighter boot for the right foot, Gary...

 

[towcat]

my double overdrive had a Zf in front and a GV behind it. imho, being in double OD at 65mph put the engine below it's powerband with 4.10 gears. I was seeing 1600rpms and any hint of a hill, the truck would bog down immediately. if I was at 2000rpm with double OD, the truck was running at 75-80 mph therefore turning me into ticket bait when towing a trailer. maybe in other states I can get away with that, but not in Kali. if you have something in tow, 55mph is the fastest you want to go or the ticket will be steep.

 

[idiabuse]

And Im complaining about the loss of one inch of tire diameter with my 3.55 geared truck.

will be towing in the morning around 8000lbs see how she handles it.

Never had double overdrive though! I sure dont want any electronics inside my slushbox either.


Javier