I've read where some truck campers specify the ratio of gearing in the differential of their trucks used for truck camping. Would anyone out there be so kind so as to explain to me what the advantages/disadvantages are to these different configurations?Thanks in advance!

The higher the gear ratio numerically (3.55, 3.73, 4.10, 4.30, 4.44, 4.56) the more revolutions your driveshaft has to turn to make the tires go 1 Revolution. This increase in gear numerical gear ratio decrease effort required to turn the tires thus making it easier for a vehicle accelerate and pull a load. If you have a light vehicle that does not pull heavy loads you can use a numerically lower gear like 3.08 which decreases the rpm of an engine at speed and thereby increase fuel economy. On the other hand, if you have a heavy vehicle that frequently pulls heavy loads you’d want a higher numeric gear ratio to make it easier to accelerate and pull heavy loads.

Generally the modern 6 to 10 speed transmissions have made changing rear gears obsolete.Now if you have an old 3 or 4 speed and you feel like you are often in the wrong gear then consider a change.

time2roll wrote:Generally the modern 6 to 10 speed transmissions have made changing rear gears obsolete.Now if you have an old 3 or 4 speed and you feel like you are often in the wrong gear then consider a change.With 10 speeds perhaps but at least some 6 speeds aren’t that different than older 4 speeds when it comes to towing heavy. Our 6 speed Yukon will top 60 in 2nd gear so it would definitely need lower gears in the rear if I wanted to tow anything substantial with it. The 2 added gears allow for lower RPM when cruising in the 40-70mph range for better mileage.

Final gear ratio is always a balance between engine torque and differential gearing. For years I drive European vehicles, who I love for high differential ratio as they take most of the grades without downshifting. My family members on other hand drive Toyotas, who I get to drive occasionally. It gets really annoying when Toyota needs to downshift with each wind gust or freeway overpass. But then Toyotas get better mpg.Same with trucks, but here, on this forum you will find "conservative" members who drove trucks with high differential ratios for decades and can't comprehend changes combustion engines made in last years. Most of the members will advise you to get high differential ratio for camper. I educated myself and for my 440 HP dually - have chosen the lowest differential ratio Ford would install, yet still the truck takes all those 15-17 miles grades we have with 6000 lb camper never dropping from overdrive at 1600 rpm. Frankly I wish I could get even lower than 3.55 differential ratio for fuel economy. It doesn't make sense to gear truck for hauling 20,000lb rigs without downshifting.Transmissions have gears for a reason.

X2, Kayteg. My new Silverado with the eight speed transmission and 3.24 rear end pulls better than my 2015 Tahoe with the six speed and 3.42.

Rear end ratios | Good Sam Community

Buzzcut1
Nomad II
Dec 27, 2019
ticki2 wrote:
BradW wrote:
mbloof wrote:
BradW wrote:
All me knows is me loves the 4.10 gears in our 2018 PSD Superdutuy when hauling our camper and towing our jeep.

IMHO: not the best gears for fuel economy.

- Mark0.

I didn't buy the thing to cruise the mall or ride up and down the road doing 85 while towing nothing; I bought it to tow a load. I'm over 18k lbs 90% of the time and drive 65ish. I would be sick if I had gone with the 3.55 gears. I could have lived with 3.73 gears, but DA Ford no longer offers that ratio.

With what I haul/tow and how I drive, 3.55 gears would not have helped my mileage any.

brad
That's because you don't have the SUPER super duty that Kayteg has .

that and Brad is not a blowhard
ticki2
Explorer
Dec 27, 2019
BradW wrote:
mbloof wrote:
BradW wrote:
All me knows is me loves the 4.10 gears in our 2018 PSD Superdutuy when hauling our camper and towing our jeep.

IMHO: not the best gears for fuel economy.

- Mark0.

I didn't buy the thing to cruise the mall or ride up and down the road doing 85 while towing nothing; I bought it to tow a load. I'm over 18k lbs 90% of the time and drive 65ish. I would be sick if I had gone with the 3.55 gears. I could have lived with 3.73 gears, but DA Ford no longer offers that ratio.

With what I haul/tow and how I drive, 3.55 gears would not have helped my mileage any.

brad
That's because you don't have the SUPER super duty that Kayteg has .
Bedlam
Moderator
Dec 26, 2019
My GVW is close to 18k lbs when I have the trailer hanging off the rear and I am around 25K lbs GCW. I am very happy with my 4.44 gearing while at the 55-65 mph travel speeds in my area.
Kayteg1
Explorer II
Dec 26, 2019
When I was moving to different state, my combo was in the range of 18,000 lb as well. That was when I got pi** ed when I notice that my 3.55 differential allows the engine take 6% long grades without dropping from overdrive.
What's the purpose of automatic transmission, when you drive 300 miles on single gear?
BradW
Explorer II
Dec 26, 2019
mbloof wrote:
BradW wrote:
All me knows is me loves the 4.10 gears in our 2018 PSD Superdutuy when hauling our camper and towing our jeep.

IMHO: not the best gears for fuel economy.

- Mark0.

I didn't buy the thing to cruise the mall or ride up and down the road doing 85 while towing nothing; I bought it to tow a load. I'm over 18k lbs 90% of the time and drive 65ish. I would be sick if I had gone with the 3.55 gears. I could have lived with 3.73 gears, but DA Ford no longer offers that ratio.

With what I haul/tow and how I drive, 3.55 gears would not have helped my mileage any.

brad
jimh406
Explorer III
Dec 26, 2019
Top speed doesn’t come into play if we do 0-60 in any case. :D
Kayteg1
Explorer II
Dec 26, 2019
Correction. I don't dare to test governor with camper on, so last time I pushed it was over 2 years ago.
Memory played with me and I check my old notes to find my 2017 governor is 95 mph. Still barely past 1/2 on tachometer scale.
Eric_Lisa
Explorer II
Dec 26, 2019
Grit dog wrote:
Kayteg1 wrote:
Darn. Dodge seems better as my Ford has governor at 85 mph.
Doing the speed at 1/2 way to redline.

Thats strange. None of the older or newer Powerstroke pickups I've been in are limited to 85.

The factory speed limit is based off the speed rating of the stock (as-delivered) tires.

My experiences back in the day... Mid 1990's Chevy Caprice with the factory 5.7 "Vette motor". Stock tires were 110mph, computer slowed down at 108mph. Exact same car with a different trim package and Z-rated tires, sold as the "Impala SS" had a 143mph governor on the "149+" rated tires. That's also why the cop cars of the era had different wheels/tires (and computer programming) compared to their civilian counterparts.

-Eric
jaycocreek
Explorer II
Dec 25, 2019
To me it is dealer availability.

If you live in Nevada (7th largest state) you have 3 locations with GM dealers. Reno area. Or 300 miles east in Elko. Or 450 miles southeast in Las Vegas.

This was a GM corporate decision some years ago. The small town dealerships weren't doing enough volume for GM so they shut them down. I used to have a Chevy and a GMC dealer nearby in Winnemucca. GM shut both of them down. Fallon had a Chevy and GM dealer. GM shut both of them down.

So why would anyone in rural Nevada buy a GM product? Why should I drive 170 miles to the nearest GM dealer when there is a Ford/Dodge dealership in every little town?

Buying new yes..When I bought a new truck in 2008 in Boise Idaho,I didn't really think about a dealer near home,I should have!The only dealer here is GM and it's 80 miles to the nearest other dealer of any kind..So servicing my new Ford included groceries and fast food we don't have here either..
specta
Explorer
Dec 25, 2019
deserteagle56 wrote:

To me it is dealer availability.

There's one brand that I'll never consider. The second one has pretty well ruled itself out so to me I'd travel a bit to buy the one I wanted.

When you spend that kind of money I'm never settle for second choice.

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