Looking at 2 identical trucks. 3.08 vs. 3.42 axle

[itguy08]

Originally Posted By: BobsArmory

14.5 MPG for the 6 liter vs. 22 MPG for the new 5.3 liter. I drive at least 50 miles per day plus I get a GM Employees Discount but I am still plugging those numbers in to see what the difference would be.


So are you basing the new truck off the EPA sticker or real world? Cause I've found with me at least I'm in the middle of the average for most vehicles not at the highway #.

Here are some #'s, assuming $3.50 for gas and 50 mile commute.
14 MPG = 3.57 gallons of gas used or $12.53 per day in fuel costs
22 MPG = 2.27 gallons of gas used or $7.98 per day in fuel costs.

Assuming you commute 365 days a year (just for the sake of weekend errands, etc), that's:
14 MPG = $4,573.45
22 MPG = $2,912.70
or a savings of $1,660.75 per year.

I dono, if the truck is paid off, it doesn't make much financial sense for the fuel savings..

As for the gears, go for the 3.42. You won't miss the economy and will enjoy the feeling of more power.

 

[The_Eric]

Originally Posted By: supton

I'd vote for the 3.42, if not keeping a known good truck and buying an econobox .



I agree on both points.

Lower cost on a car, better mileage, cheaper licensing, cheaper maintenance- it's a win/win situation, unless of course you use your truck to haul stuff for work.

 

[Brian Barnhart]

I have an '06 4X4 with the 5.3 and 3.42. Wish it was a 3.73 or 4.10. About 1500 RPM @ 55 MPH. Doesn't take much of a grade to cause a downshift. Towing a heavy load is like pulling stumps. I'd be surprised if the difference between 3.08 and 3.42 would make even 1 MPG difference. It will make a huge difference in drivability and especially launch from a stop.

 

[mrsilv04]

Originally Posted By: Brian Barnhart
I have an '06 4X4 with the 5.3 and 3.42. Wish it was a 3.73 or 4.10. About 1500 RPM @ 55 MPH. Doesn't take much of a grade to cause a downshift. Towing a heavy load is like pulling stumps. I'd be surprised if the difference between 3.08 and 3.42 would make even 1 MPG difference. It will make a huge difference in drivability and especially launch from a stop.


They're not 4 speed transmissions anymore...

 

[Nate1979]

Over on the GM forums there are a number of threads on towing. Quite a few people have commented their regret at getting the 3.08 rear axle. They say it is a dog and that GM only offers it to win the fuel economy wars.

 

[jmb3675]

Originally Posted By: The_Eric
Originally Posted By: supton

I'd vote for the 3.42, if not keeping a known good truck and buying an econobox .



I agree on both points.

Lower cost on a car, better mileage, cheaper licensing, cheaper maintenance- it's a win/win situation, unless of course you use your truck to haul stuff for work.


Actually you add the licensing and insurance cost of the car to the cost of the truck. For me the licensing and insurance together per month for my Focus is 28 bucks a month. But it saves me 120 a month in gas. So I actually only save 92 per month. But then adding what the car cost me, I will round up to 3000 bucks, divide that by the 92 bucks I save every month in gas, it will take 32.61 months to break even. Which is 2.72 years, or just under 2 years and 9 months. Not counting maintenance savings on the truck like more expensive tires and oil changes, etc. So my beater car has to make it about another year without a major repair to have a decent cost saving. Assuming my math is correct and logical anyway. But since I love my truck and want it to last a lifetime, and I enjoy the convenience of the car for daily driving, the cost saving isn't as big of a deal for me. But something to think about.

 

[morepwr]

3.42 is the way to go. The slight difference in MPG will be offset nicely when you use the truck as it is made to be used.

 

[Brian Barnhart]

Originally Posted By: mrsilv04
Originally Posted By: Brian Barnhart
I have an '06 4X4 with the 5.3 and 3.42. Wish it was a 3.73 or 4.10. About 1500 RPM @ 55 MPH. Doesn't take much of a grade to cause a downshift. Towing a heavy load is like pulling stumps. I'd be surprised if the difference between 3.08 and 3.42 would make even 1 MPG difference. It will make a huge difference in drivability and especially launch from a stop.


They're not 4 speed transmissions anymore...


That's true, a 6 speed will do a lot to offset the difference in axle ratios (so a 6 speed 3.08 will probably perform as well or better than the 3.42 4 speed. But since the OP was asking about towing, I would still go with the 3.42. Even if the 3.08/6spd is better than what I have, I would still consider it a marginal tow vehicle.

The difference in engine RPM between the two would be 11%, or about 200 RPM at 70 MPH.

Based on my experience with the 5.3, I wouldn't choose a 5.3 for towing regardless of the other particulars unless I was only going to tow 2000 lbs. or less on an occasional basis. It simply lacks the grunt of a good tow vehicle.

 

[Cujet]

Don't forget to account for the tire diameter.

My Ford F150 has 20 inch rims large diameter tires. The 3.55 differential results in 1600 RPM at 60MPH. I'm not at all sure the engine would be happy at lower RPM's at the same speed.

 

[SteveSRT8]

My favorite fleet truck is an 05 Silverado with the 3.73 locker rear end.

The gearing totally transforms the 5.3, turning a gutless wonder into a barnstormer. Gas mileage is BETTER in the city and the same on the highway.

The newer six speeds have simple programming changes available that REALLY light them up. Due to the trans having a very low first gear they can easily run taller gears for better economy yet still scamper pretty good...

 

[hattaresguy]

I'd get the 3.08's since your only towing a couple of light ATV's. 3.08's are good to 7k 3.42's to 10k, your probably at what 3k maybe?

GM gears down the transmissions, 2014 final drive with 3.08's is pretty much the same as 2013 with 4.10's.

I have towed double ATV trailers with E class and S class Mercedes and never had a problem. They are light.

Buy the truck for what 90% of its yearly mileage will be. In most cases that's lightly loaded with one or two people in the cab.

 

[kkreit01]

I would always pick the lowest gears -- even if not towing. When I bought my Ram, that was one criteria -- 3.92 gears. I never regretted that decision. MPG isn't going to be great anyway. I'd sacrifice another .5-1 mpg just for the drive-ability. 3.08 is aweful high.