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Need advice on rear axle ratios.............

4K views 14 replies 7 participants last post by  Hikes run 
#1 ·
looking at 2 GMC sierras -one has a 3.08 rear axle ratio - the other 3.42....which would do better in the sand ? I know the 3.08 would give slightly better mpg's but I'm more worried about cooking the tranny or digging in the tires due to excess speed/torque? any help appreciated , thanks
 
G
#3 ·
Measure the diameter of the tires. The rule of thumb is that the optimum gear ratio ( theoretical - get as close as possible ) is Tire Diameter in inches X .12 = Axle Ratio. So, 33" tires would be 33 X .12 = 3.96 ( 3.73 or 4.11 ).
 
#5 ·
Either gear ratio would work fine on the beach.Towing is the difference.I have a 2014 Silverado with 3.42s and its good all around.Dont need to air down unless the beach is really chewed up.One note is that if its a newer truck then make sure you turn traction control off before going on beach or you wont be happy.
 
#10 ·
Very interesting read guys. I recently picked up a 2011 ram 1500 and it has the button you have to push to turn traction control off. I NEVER would have known to do that! Now if I can just figure out what rear end is in it I'll be good to go. Where can I find that information?
 
#12 ·
looking at 2 GMC sierras -one has a 3.08 rear axle ratio - the other 3.42....which would do better in the sand ? I know the 3.08 would give slightly better mpg's but I'm more worried about cooking the tranny or digging in the tires due to excess speed/torque? any help appreciated , thanks
Put the gear shift in 1 and you shouldn't overheat your transmission. It will keep the transmission from searching for the best gear to be in.
 
#13 ·
I agree with this, pull the gear selector down to L or 2.
If you had a manual transmission, you wouldn't get much out of second gear at the slow speeds we are supposed to drive.
These modern day automatics, in their quest for every inch of gas mileage, will always go up a gear or two, and lug along until the speed picks up. That leads, in the sand, to heat, and slippage in the viscous coupling, killing the box.
 
#15 ·
I did some searching and found where I could enter my VIN number and get the build sheet for my truck that shows all standard and optional equipment on it. Very cool for us used Dodge guys. It has a 3.55 rear end with 33's. From what I've read that's pretty much middle of the road kind of gears I guess. My previous truck was an 05 Ram 1500 with the smaller 4.7 liter engine and it did excellent in the sand. It did't get stuck in 5 years and sure pulled its share of folks out. I'm not sure what gears it had though and no way to find out now. Not sure how much difference tires make in sand but I was running on Cooper Discoverer A/T3's and I absolutely loved them, best tire I've run on by far. That's what's going on the new truck as well.

The new truck has a couple of nice options I would have otherwise not known it had without finding the build sheet though. Heavy duty engine cooling, Heavy duty transmission oil cooler and 5 additional gallons of gas on a 26 gallon tank!

Here's the link to get the build sheets if any of you Dodge guys are interested. It spits out a printable PDF in a few seconds but only works on 98 and newer. Enjoy!

- Go to this website --->
- Click on the link down the left side of the page that says "Equipment List"
- Enter your VIN in the smaller search bar and click search
 
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