Am I Getting Old? Gear Question

I bought a used '14 crew bighorn 4x4 with the 5.7.

Mopar connect says I have 3.21s but reading in here about the huge improvement of 3.92s over 3.21s etc makes me think I may have 3.92s. I have relatively beefy (stock size) BF Goodrich KO2s on her, but a little tap in the parking lot, or a good (not wot) acceleration, hell, even just a little throttle and I'm breaking the tires loose.

0-60 is quite impressive as well.

Is there a way to tell physically on the truck without opening anything up what gears my truck has in it?

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There will be a tag on your rear axle that says your gear ratio. Just hop under with a flashlight

Steveo8x8 said:

There will be a tag on your rear axle that says your gear ratio. Just hop under with a flashlight

Click to expand...

Lol. Well.....

I just went under my truck and the only part of the sticker left with the ratio is the '3'.


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I mean, I guess everything else on the build sheet is right.

If the 3.21s are truly the gears I have, my tire budget would have to get bigger with 3.92s.

My previous truck was a 2006 avalanche 5.3l.

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You can find your gear ratio easily with this method. All you need is a jack, some jackstands, and knowing how to count helps too.

You're going to have to put the truck in nuetral or out of gear, so safety first! Do this on level ground, and be sure and chock the front wheels so the car can't move. It helps to have someone there in the truck just in case...

First, do you have a posi or limited slip rear? If you're not sure, just jack up the rear so both tires are off the ground and put your jackstands under the axle. Now turn one of the tires. If the other tire turns the same way or doesn't turn at all, you should have a posi or limited slip. If the tire turns opposite of the way the first tire spins, then it's probably an open rear end.

If you have a truck with a posi or limited slip rear, jack up the car and get both rear tires off the ground. Now put your jackstands under the axle. Make a line on the pinion yoke and onto the rear end with chalk or a grease pencil. Do the same to the tire on the truck, so you can see when the tire has rotated exactly one turn.

Now count the number of turns of the driveshaft that it takes (use your chalk marks) to make the rear tire turn one complete rotation. (Transmission needs to be in neutral or out of gear.)

If your car has an open rear, jack up only one rear tire and leave the other on the ground. Now put a jackstand under the lifted side. Turn the tire and again count the number of turns of the driveshaft, but this time you must turn the tire two full rotations.

So:

Posi: Jack both wheels off the ground. Turn one wheel 1 complete turn.

- Count the turns on the drive shaft.

Non-posi: Jack one wheel off the ground. Turn the wheel 2 complete turns.

- Count the turns on the drive shaft.

you may well have 3:21 withe 8 speed trans. the 3:21 with the 8 speed will actually pull better than the 3:92 with the six speed due to the gear ration inside the trans.

Go 75, if you are at 2000 RPMs then it's 3.92s.
Simple


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You can also check out the Build Sheet at the link below. That will show what it has off the assembly line.

Ram Trucks - Contact Us

click "Equipment listing" in left hand column

enter VIN #

Done


Moses

LVT,

3.21 ratio with 8 spd, 90mph=2000 rpm

My truck with 3.21 is much snappier than my 2008 Silverado with 5.3, 3.73; I agree with your assessment.