Have a 92 full size 4X4 blazer and need to know my gear-ratio, no markings on the axle. Need to replace the rear-end but cant till I know the ratio. Has to match with the front axle right?

 

You can pull the diff cover and either count the teeth or read the ratio off the ring gear.

11 41 == 3.73
10 41 == 4.10

Here's the ring gear stampings from my 14-bolt full floater:

And from my 3/4 ton donor 10-bolt front axle:

To give you some examples of what to look for.

 

Thanks for the info. This is a real help!