3:55 or 4:10s?

[89ford]

Ok well I have access to a set of 3:55s but my truck is currently running 4:10s I pull a trailer at least once a week it's a 18' car trailer but I am hoping to get my gooseneck ball hooked up I guess I'm asking what kind of mileage could I expect and could I still pull my trailers easily and do good pulling a pulling sled?

 

[damac]

I am no techie but it looks like I am regratting going from 3.55 to 4.10 on the truck in my sig.

One thing I must say is that I am a week or so away from installing new ip and injectors, I think my truck has the originals.

Since I installed these gears all I have noticed is like a 5mpg mileage loss, screaming at highway speeds with no trailer, and what I would call decreased power when towing especially up grades?

I can't explain any of it, same truck setup and same load, I just did it because I got a deal on parts and thought maybe it could help with the truck screaming in 1st gear on some moderate hills? We don't even tow heavy, just toys. Too bad I already threw away my other axles.

So I am not really of any help but I will be glade to chime in within a couple weeks of getting the truck going and will tow the same load and see if power, etc. improves and let you know.

 

[93f250idi]

Its according to how much towing and highway driving you do. I hardly ever do any highway driving so 4:10s were a plus for me. the first time i owned this truck it was running stock tires (265/75/16) and i could average about 17-18 mpg city if i babied it, that was with 3:55s. now with 4:10s and 35s i can average 15-16 mpg city prolly better if i babied it. i love the 4:10s especially with a load behind it!

 

[brdmh44]

If you pull frequently keep the 4:10's.... I have one truck that is a 6.9/C6/3:55 and another that is 7.3/E4OD/4:10 (neither trucks have turbos) and the 4:10's out pull the 3:55's any day of the week.

As for pulling a sled, the only way your gonna be competitive is by them allowing you to pull in the "stock" gas class.....most sleds run in too agressive for our low HP rigs

 

[89ford]

Well right now I pull in 8500lb class they limit you to 15 mph I do pretty decent at it getting a 196 on my last run

 

[david85]

Is your truck turbocharged? What transmission do you have? (overdrive?). 2wd or 4wd?

For 8500lbs I would be tempted to say keep the 4.10s, although if you do enough empty driving inbetween towing, you may be better served by the 3.55s. With a turbocharger, you will not suffer as much by going to taller gears.

 

[89ford]

Currently I do not have a turbo hopefully getting that within this week and my truck is a 4wd with the 7.3 zf5

 

[david85]

In that case, either setup will do.

With a 4wd, you have the option of using low range if you find yourself in a really steep incline and have that trailer behind you. With a turbocharger, you can probably cruise comfortably in 4th gear at highway speeds if you need to get the RPMs up, but 5th may be asking too much depending on the conditions. 4.10s will still be ideal if all you ever did was tow with the truck, but with a turbo, you'll do fine with the 3.55s.

I'd wait until the turbo is in and run it like that for a while since you're already going that route anyway.

 

[Rot Box]

If it were me and I had a C6 or T-19 I'd suffer with the 3.55's and run them.

If I had an overdrive I would go 4.10's and never look back

 

[Diesel_brad]

If it were me and I had a C6 or T-19 I'd suffer with the 3.55's and run them.

If I had an overdrive I would go 4.10's and never look back

What he said. If you go to 3:55s and have a load on a hill starting out, you will SMOKE the clutch trying to start out

 

[Simp5782]

I ran 3.55s in my 85 with a 6.9 NA and a 4spd and I do not notice any difference in towing after changing to 4.10s. you notice without a trailer but getting one moving im using 2L and shifting out and back to 1st once i get rolling. I am grossing 33 - 40k 130-160miles round trip 2 - 3 x a day. I get around 9 to 11 empty and loaded thru the day. Around 45gal of diesel. I think I was using around 47 or 48 gal a day with the 3.55s you wont notice that much of a difference. Weight is weight once you get it moving its gonna go. My biggest strain now is breaking u joints from time to time getting things moving. with the 3.55s I was getting around 13/14 with an empty GN that is around 9k on long hauls with the 3.55s and 4.10s. with no load i was getting 21/22 with 3.55s and 18/20 with 4.10s at 58-62mph range on hilly roads. In my opinion with a good tough driveline you can do almost anything with the 3.55s or swap in some 3.73s its a good mid range gear.