What Rear End Ratio Do I Have?

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Delano1981

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Hello Everyone,

I am trying to figure out the tow capacity of my 2007 Ram 1500 QC Hemi 4X4 truck. I have already done a lot of searching and I am still not sure what my gear ratio is. I already looked in the glove compartment and there is no sticker in it. The equipment list for my truck says 3.55 for the standard axle ratio. However, I have the tow package and 20" wheel package. The towing spec PDF for this truck only shows a 3.92 ratio for the QC Hemi with 20" wheel package. The rear axle is a corporate 9.25 LD. I am assuming it has the 3.92 because the tow specs only show that ratio with the 20" wheels. Is there another way to find out?

Thanks
 
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Delano1981

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I did get the build sheet based on the VIN #. The only thing it lists is a 3.55 ratio as standard equipment. It also says I have Customer preferred packages 26G & 2TG. The actual truck has the factory 20" rims & tires which is not listed in the build sheet unless it is part of the preferred packages. The towing specs sheet only lists a 3.92 ratio for the 20" tires. I forget to mention it is the SLT model truck.
 

ST-8

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Look under the truck at axel itself. Should be a tag near the passengers side axel
 
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Delano1981

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Thanks for the replies everyone. I finally figured out my gear ratio by lifting the tire off the ground and spinning it 10 turns and counting the drive shaft revolutions. Drive shaft turned 17.75 times per 10 turns of the wheel. 17.75 X 2 = 35.5 / 10 gives me 3.55.
 

sean_wilbur

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Where is this support home page? I'm trying to figure out the same thing about my gear ratio
 

MADDOG

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I did get the build sheet based on the VIN #. The only thing it lists is a 3.55 ratio as standard equipment. It also says I have Customer preferred packages 26G & 2TG. The actual truck has the factory 20" rims & tires which is not listed in the build sheet unless it is part of the preferred packages. The towing specs sheet only lists a 3.92 ratio for the 20" tires. I forget to mention it is the SLT model truck.

Did you buy the truck used? If so, some previous owner may have updated the wheels & tires with OEM take offs.
 

Redtruck-VA

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Agreed, 20" rims usually have a 3:92 gear, however there are a lot of folks who put the 20's on their trucks with the 3:55 gear. 07 is close to 10 years old and if bought used there could be a lot that has been done to the truck.
 
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