What's my gear ratio??

[LeafspringMARINE]

The million dollar question....

How do I find out what my gear ratio is so I can get the correct rear end from the junkyard? I even called the Jeep dealer & the service guy said he "didnt know". WTF??

[BucketOKarma]

What are the drivetrain specs of your jeep (engine size, auto trans, or std?) and has it been geared before? You're looking for axle gearing, not the ratio, that's a tranny/transfer case thing ( I think, but I'm not quite certain, so I might have made a fool of myself).

Look at the rear axle, next to or on the rear diff, should be a metal tag. Your gearing will be on that tag if it's still there and readable. If not, check your front diff for the same tag, and read that, again, if it's still there and readable. If your jeep has been geared before, the tags might have been removed.


I really hate to say it, but you might want to check the Jeepforum tech area, find your jeep in the stock specs section, and figure it out there if you can't find what you're looking for here.

[airforce26yrs]

This article might help.

http://www.jedi.com/obiwan/jeep/misc/gearratio.html

[Doppler]

Intead of dropping the drive shaft you can also tape a piece of string, 18 to 24 inches long, to the bottom center of the drive shaft, then turn the tire the necessary revolutions depending on differential type, and then count the wraps of the string. 3.5 wraps is 3.55:1; 3.75 wraps is 3.73:1 and so on. Good luck!

[BomberJeep]

Your rear diff should have a tag on it saying what gearing is in there. If not you could get a build sheet from your local stealership for free just give them your vin

[jackhammer]

manual yj 4cyl is 410
auto yj 4cyl is 373
Its only when you get into the 6cyl that its a game.

[MJMPC]

With all the mods people do it is hard to tell. Best thing is to pop the diff cover and look at the numbers on the ring gear.

[jackhammer]

The numbers on the ring gear need to be divided on the dana 30. Not sure on the 35. If I remember correctly theres 2 sets of numbers and if you divide them by each other you get the ratio. My 8.8 just had the ratio marked on the ring gear

[Grevus]

I used to know a formula that would take your tranny low gear, transfer case low gear and your ring and pinon gear ratio and tell you the over all gear ratio.. I think it's just adding them together but I don't remember..

[highlandercj-7]

The front diff usually has a tag on it that is most legiable. Most common in a YJ are 410's, 355's and 307's.