Hey guys, I've got a question about my rear end and want to make sure I understand the issue fully before I raise an issue with the dealer.

I just bought a 2016 2.7 XLT Crew last night with 302A equipment group and a number of other options. Among those options was an upgrade to 3.73 gears according to the window sticker. I was going over some things tonight and noticed my axle code lists "27", which appears to be a 3.31 gear.

Would a 3.73 have come in a 9.75" and a 3.31 in an 8.8"? I have an 8.8 in my truck plain as day, the housing is a rectangular shape and has definition around the ring gear.

I'm not quite sure what's going on here. Thanks for your help.

 

Hey guys, I found another sticker and wanted to add that information here. The sticker on the axle tube itself is still legible and reads 3E73, which matches the window sticker so that is accurate.

I expected to see a 9.75" under the truck based on the ratio, not an 8.8 although the 8.8 should serve me just fine.

 

Your axle code on the door jamb reads 27? if so, your truck has 3.31 gears. I believe the 3.73 should have the 9.75 diff and 3.31 and 3.55 have the super 8 diff.

 

Do the math to confirm it. Figure out what your RPMs are at a given speed (ideally, use Forscan/Torque/etc. or the cluster test mode for a bit more accuracy) and, using the trans ratio for whatever gear you're in and the tire revs/mile, you can figure out what the actual ratio is.

 

The engine and payload package determines the axle you get, not the ratio. My truck has the 9.75 axle with 3.31 gears.

 

Here's what I've got. Door label says 27, window sticker says 3.73 with a trailer tow package, rear end itself is an 8.8 with a sticker that says 3E73.

What do you guys think?

 

Id go off the axle tag. You have an 8.8 with 3.73 gears.

 

For what reason is the door label showing a different code? Was the gear changed after it was initially built but before delivery?

 

It may be a bit of a pain, but you can block the front tires, jack up the back and put it in neutral. Count the revolutions of the drive shaft as the tire rotates one revolution. That will give you the ratio.

 

Thanks, I'll probably do that tonight to satisfy my curiosity.