How can you tell for sure what gear ratio you have and if you have a limited slip rear end?

 

Lift 1 wheel, turn tire 1 revolution, count the drive shaft revolutions and divide by 2.

 

The easiest way is to go to a dealer and give them your vin and have them check it.(if they will and if you have a dealer you like and trust) That will tell you what your truck came with.
Jay

 

I'm with Billie. You never know what's been put in at the factory anyway.

As for limited slip... never did one with these trucks so I'm not sure if the old rule of lifting the rear and spinning the tires is true on these. You know one goes forward and one goes backward.....

So I'd jack up one wheel and put the truck in gear. If it moves forward off the block, you must have limited slip I suppose.

Or you could back onto your neighbor's driveway and light them up and see if you leave two smoking streaks or one...

 

You should find the gear ratio posted plainly on or in the truck. Like inside the glovebox or doorjam or underhood.

JMO

 

After the 04.5's they no longer put the gear ration in the glove box, it only came on the window sticker that I know of. Get your dealer to get you a copy of the build sheet and it should be there. Most auto's came with the 3.73's but if it was special ordered it may have the 4.11's. Also think many of the 4x4's came with limited slip differentials but again not all. So if you have an auto 4x4 odds are 3.73 with limited slip. If 2x4 don't know other than probably 3.73.