# Buying New Tv - How Important Is Axle Ratio?



## cerealcamper (May 25, 2009)

We are looking at buying a new pick-up as a daily driver, and for monthly summer camping trips. Our trips here in Michigan are usually less than a 4 hour drive and are relatively flat, pulling a 21RS. For multiple reasons, only looking at GM models. Probably not able to swing a Duramax at this point (maybe overkill for us at this point).

In the GMC Sierra 1/2 ton crew cab models we have looked at, they have a 5.3L engine with a 6 speed transmission - and here is the interesting part - have a 3.42 ratio axle. Seems low to me with my limited knowledge. According to the salesman, all the 6 speed transmission models have the lower ratio, and that "the transmission gearing makes up for the axle". The HP and torque of the motor look decent and the tow rating is still pretty acceptable. How big of a deal is the axle ratio in this situation? Any other factors I should be looking at to ensure I get a decent vehicle to handle my towing situation?

Thanks in advance for your perspectives!

Gary.


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## Ghosty (Jan 17, 2005)

i had a 2005 5.3L 1500 Silverado CC which pulled my 23RS absolutely NO problems... of course i did have 3.73 and not the 3.42 but the higher rear-end is only important if you are needing more "towing".. anyway...

The dealer is wrong -- you CAN get a 3.73 in any model since like 2000 ... he sounds like he is just trying to move inventory ... 3.42 good for driving and light hauling ... 4.10 great for towing .. 3.73 right in the middle

i am going to say that you need to stop for a second and actually look at the 2500HD 6.6L Diesels .... here is my reasoning...

1. Odds are one day you are going to get a bigger trailer -- and will need a bigger truck .. and the prices will NEVER be this low again .. so if you spend more NOW you will save MORE later

2. You are one day - probably soon - be pulling the trailer up a hil and turn to your wife and say "$%@#, I sure wish i had a bigger truck!!"

3. In my diesel I get 12 towing - 14 city - 20 Hwy (in my gas Silverado I got 8-9 towing, 14 city, 19 hwy) .. so i am actually helping the environment and saving money at the same time ....









4. You are going to get tired of hearing that GMC go from OD to 3 to OD to 3 to OD to 3 OD to 3 to OD to 3 to OD to 3 OD to 3 to OD to 3 to OD to 3 OD to 3 to OD to 3 to OD to 3 OD to 3 to OD to 3 to OD to 3 OD to 3 to OD to 3 to OD to 3 OD to 3 to OD to 3 to OD to 3 OD to 3 to OD to 3 to OD to 3 while towing.

5. Chicks dig diesel trucks.


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## Justman (Jul 22, 2006)

Howdy!

Believe the 3.42 gear ratios and the 6 speed transmission are meant to increase gas mileage---not towing capability. Great for a daily driver, but not as good as previous years for towing capability. I'd question the pitch about the transmission making up for the gear ratio. On my Silverado, the 6th gear is essentially an overdrive. From what I gather, GM added the 6th gear in 2006 to increase gas mileage while not towing. Believe they're doing the same on the newer trucks. Bottom line, I think the salesman is trying to sell you a truck. You may be fine if you tow in 4th or 5th, but with that gear ratio you're not going to want to tow in 6th.


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## RI-23rs (Jul 7, 2008)

I was looking at some GMC's this year and all the salesmen I spoke to recommended the 3.73 It has the towing capacity and will not break the bank in fuel. I presently have a Durango with 5.7lt and 3.55 rear and it pulls my 23rs great.


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## Duanesz (Jul 10, 2009)

Get more gear 3:42 seems a little low. You might get a bigger trailer one day and need the gear. You can buy alot of gas for what a diesel is going to cost you. But it sure is nice to be pulling a camper and pull up to a light and beat the rice rocket next to you when you have to merge ( I have towed mine with my dads 08 duramax wow does that thing drag good) Dont let the truck salesman sell you something off the lot make him find you a truck with the right gear ratio. Dealers have 90-100 day supply of trucks on hand they can find what you need.

Duane


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## gonewild (Mar 13, 2009)

I have a 2005 Sierra with the gears you are referring to. I am currently in Yellowstone with my 210 RS which I towed from NY (great trip). The difference is that I have a 4 speed auto. I tow in 3rd with tow-haul on(won't stay in OD). It does well on flat, but the mountain passes <9,000ft (5 miles <6* of incline) are not fun. I am already looking for a 2500HD Diesel. As far as handling the weight the truck does well. I have upgraded the hitch, KYB shocks and Equalizer. If you don't plan on ever heading to the mountains you will be OK.

Good Luck with your decision.


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## muddy tires (Jun 22, 2007)

Duanesz said:


> Dealers have 90-100 day supply of trucks on hand they can find what you need.


Wow. Things are certainly different north of the 49th. Dealers here have a very hard time getting trucks, especially the 2500/3500 crew cabs. I was looking at one at the dealership that was brought in from Winnipeg for a customer (about 2200 km)!


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## Ghosty (Jan 17, 2005)

muddy tires said:


> Dealers have 90-100 day supply of trucks on hand they can find what you need.


Wow. Things are certainly different north of the 49th. Dealers here have a very hard time getting trucks, especially the 2500/3500 crew cabs. I was looking at one at the dealership that was brought in from Winnipeg for a customer (about 2200 km)!
[/quote]

YEP ... but it may be worth the trip to go below even the Mason-Dixon line ... Cavender Chevrolet in San Antonio has over 50 2008-2500HD/3500HD in stuck and about 60 2009 .....

Its a great time to buy a diesel ... yes they are more expensive but the savings right now will never be seen again -- the car companies have learned their lessons on over producing and expecitng folks to buy whatever they make....


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## KosinTrouble (Jul 18, 2005)

I bought my truck last year and it has the 4.1 gears. It is great towing my 26rs, I got the bigger gears because we are/were planning some cross Canada trips with the trailer. It has the "smart engine" which drops to 4 cylinders when not under stress. And for my commuting it is fantastic because 80% of my trip is in a 90km zone it is usually in the 4 cylinder mode and avg about 8L/100km. Now in your case I would definitly make sure the truck has 3.75 gears in case you move up in trailer size and when you hit the hills.

Kos


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## Scooter (May 9, 2005)

Tire size and terrain also plays an important role in Gear ratio 
When taller tires are installed on a truck but the axle ratios stay the same; the effective gear ratio is reduced. 
A 3:55 with smaller wheels is going to tow a lot different than a 3:55 with larger wheels for example.

I've towed with 3:42 and 3:55. 3:73
3.42 I wouldn't even consider for towing (good for fuel economy) Tried it a few times with a ford f-150 5.4l early on , *absolutely awful *
3:55 did fine for light towing but wasn't optimal in the mountainous area where I live.
3:73 seemed to work the best for me towing in the mountainous Terrain , keeping 
my truck optimal in powerband with engine, tires, transmission, and Axle ratio all working 
together *in combination* to provide best optimal towin performance-

my trade off is *slight *ding in fuel economy)

If I lived in FLA, for example and was only going to tow a few times a year I probably would use 3:55 , 
But in VT 3:73 seemed the best compromise.


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## PDX_Doug (Nov 16, 2004)

Gary,

As with most things, gearing is always going to be a compromise. Bigger numbers (lower gearing) such as a 4.10:1 rear end translate to added pulling power, acceleration and lousy fuel economy. Smaller numbers (higher gearing) such as a 3.42:1 equate to higher top speed and better fuel economy. The trick is to figure out what you need to get out of the gearing.

If you have a diesel with endless torque, that added pulling power is not needed as much, and you can get by with higher gearing. On the other hand if you have a small block gas engine, low gearing can go a long ways towards making up for the relative lack of torque the engine is producing.

But how much pulling power do you need? That depends on a lot of factors including elevation, terrain, wind and of course how big and heavy the trailer is you are trying to pull. If you stay in the flat lands and tow a smaller trailer in low head wind conditions, the 3.42:1 gearing you are talking about will probably get by okay. But start adding hills, head winds and weight to the equation and that 5.3 is going to run out of oomph in a hurry. And, at least personally, I like to have a little reserve in the bag. From a longevity perspective, the easier I make life on my drive train, the less likely it's going to be to ask for a trip to the dealer!

Bottom line... Take a good hard look at exactly what your towing expectations and desires are, and go from there.

Happy Trails,
Doug


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## nynethead (Sep 23, 2005)

I pulled by Outback 29BHS with an 05 chevy 5.3 and 3.42 gears. worked except when you came to a hill. traveling out to pa was white knuckle doing 50 in second gear pulling 4k to maintain the 50. used it for about 9 months and then bought a diesel.

It might work for the 21, but I do not think you will be happy towing.

gass mileage should be good, thou my diesel gets the same mileage around town.


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## Collinsfam_WY (Nov 9, 2006)

Axle ratio = very important. For new trucks...

Gassers: 4.10's or 4.30's
Diesels: 3.73's

-CC


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## cerealcamper (May 25, 2009)

Thanks everyone for the great feedback so far!

Based on all the comments - definitely need to think harder about the diesel option. Especially since I have now learned from Ghosty that "chicks dig diesel trucks"!

I have the GMC dealer now looking for other options outside his lot. One idea is apparently the "Tow Max" package which has a better axle, as well as the bigger 6.0L or 6.2L engine and a few other items. Haven't seen a vehicle with this package so far. Anyone have experience with that setup?


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## Collinsfam_WY (Nov 9, 2006)

You will be happier with the 6.0l or 6.2l motor than the 5.3l. Because the truck will be daily driver, you need to consider whether or not diesel is a viable option. Your daily driving needs might eliminate the diesel from being a possibility - or not. DPF's can be a pain.

-CC


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## bbwb (Apr 4, 2008)

As the others have stated go with the 6.0 or larger gasser or the diesel route. I pull our 23rs with a '06 5.3L (all aluminum) and 4.10 gears. It pulls the camper okay but will tend to run out of steam on steep grades. The truck originally came with the 3.42 ratio and struggled with this camper...loaded semi's passed me on the slightest of grades. With the 4.10's I get about 8 mpg pulling the trailer and 19 mpg unloaded at 60/65 mph.

bbwb


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## California Jim (Dec 11, 2003)

3:73's or bust.


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## KosinTrouble (Jul 18, 2005)

I really dont see the need for a 6.0L or diesel for a 21rs. It is not like it is the krs, where you are bringing bikes or quads.

The new Chev or ughh ford with the 5.4l engines with tow packages can easily handle a 21rs while getting way better gas milage for your daily commute. The Silverado will kick down to 4cylinders at cruising speeds, which helps with gas miliage as well. And it still allows you to upgrade your trailer later on unless you move past the 26ft range, in which case 3/4ton would be much better.

Kos


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## phxbrit (Jul 24, 2007)

I like the idea of going to the diesel, towmax or even the new Tundra. If you stick with Outback there isn't a whole lot of selection less than 26 feet for an upgrade down the road. We bought a 21rs because we had a 99 F150 (/c 3.55 axle) and when we ran the numbers, and with an 80% margin, we really didn't feel comfortable towing anything bigger than a 23rs. Even though we really wanted the 25rss at the time. It didn't take but a year of towing to move on to a diesel. It was painful towing up steep grades and forget about a headwind. A strong headwind on flat ground and the engine would be screaming just to hold 45 mph. Which is no fun when cars are flying around us at 75. We were a road hazard on the interstate.

With my diesel I get 17.5 miles/gallon commuting, that's about 5 miles of street traffic and 10 miles of highway traffic each way. Towing from 1500 feet to 9400 feet, 230 miles and back I get about 12.8 miles/gallon. With my F150 I used to get about 8.5 mpg towing and 13 mpg commuting.

In the long run it will cost less in fuel to run a diesel engine. It may cost an extra $7000 to go diesel vs. gas in a 3/4 ton, but your resale value will be higher. Let's say your resale value will be $4500 more than an equivalent gas model after 5 years. The true cost will only be $2500 more for diesel vs. gas. It won't take that long to recoup your $2500 in fuel savings. Please, don't get too hung up on the added cost of going diesel. Other cost of ownership are hard to tell versus a gas engine. A lot has to do with the version of the engine and much of that is luck. There are many out there who have the problem versions of the engines and never had any issues.

The other thing about diesels. When you crank over the engine and listen to that clatter, you can turn to your wife, grin and sing "She thinks' my tractor's sexy..." The look when she rolls her eyes is worth the extra seven grand alone if you ask me.


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## shaela21 (Aug 16, 2005)

I have the 5.3L with 3.73 gear ratio, and I would never go below that for towing the 21RS, either engine or rear end. I wish I had the 4.01 ratio, but I have been happy with what I have. Go for the biggest engine you can get (minimum 5.3L), and the lower ration (3.73 or 4.01) and this will have a good tow vehicle. And good for you for choosing GMC.


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## Nathan (Jan 2, 2007)

phxbrit said:


> The other thing about diesels. When you crank over the engine and listen to that clatter, you can turn to your wife, grin and sing "She thinks' my tractor's sexy..." The look when she rolls her eyes is worth the extra seven grand alone if you ask me.


LOL, now That is funny!









As for cost, I love my diesel, but they are expensive to maintain. Oil changes are 4 times the cost (~$80-$100). Fuel filters need replacing every year. The charge for the dealer to do mine was ~$150

My F150 cost $50/year to maintain (2 oil changes at 7500 mile intervals). My Super Duty cost over $300 over the same period. 
Will I go back to gas with the next truck? NOT A CHANCE!!!


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## webeopelas (Mar 11, 2006)

That's why I change my own oil and fuel filters.

Oil change is as low as $40 if I use Rotella T.

Went up to $60 this time because I put Rotella Synthetic in.

Maybe the Ford filters are harder to get to, but mine is right on the firewall, turn a petcock to drain the fuel, unscrew the top, put in the new filter, button it back up, turn the key on and off a couple of times to ensure the pump has refilled the reservoir, and I am done. Can't see paying a dealer $150 to do that.

Takes me about 30 min to do. Local landfill will take the old oil, or most time Jiffy lube or others will take it as well. My 3 gallons is a drop in the bucket of what they get rid of. Some parts stores also have used oil collection centers.

My gassers were changed at 3000-4000 mi. My diesel is changed every 7500-10000 depending on how much I have towed. Which is in the "Heavy Use" range recommendation by Dodge.

So I change oil only half as many times in a year. So $60/2 = 30. Which you can't get a gasser oil change for anymore without a coupon or doing it yourself as well.

At a minimum, my maintanence costs are equal, at best less than a gas engine.


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## Tyvekcat (Aug 28, 2007)

yeah, What Webeopelas said. Diesels rule.









Maintenance, fuel filter, 3 gallons Valvoline Cummins approved engine oil, check the power steering fluid, change an air filter with a Fleetguard from Genos garage every now and then. Check the GO-5 coolant (Zerex), and change that ATF (if you have the slushbox) at about 40k, check the differential oils and grease the ball joints and carden joint on the front drive shaft @7500 mile, we're done.

I had the 3.55 in my previous Dodge. It was good for running up and down the interstate, unloaded. Here in the Hills of Virginia, I got tired of 3k rpm up Fancy Gap. I wouldn't trade my 4.10's for anything.
Same speed up the hill/mtn as on level ground. ( no level ground around here). LOL If the camper thing goes away, truck stays.


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