Is there any way I can find out my gear ratio? My front differential is leaking and ism trying to see which one I need to buy to replace it so I can rebuild this one.

 

I don't see the year of the truck in your post or sig. I believe pre 96 all have codes in the glove box. Not sure about 96-98. If your not sure the truck is all original or you can't read the codes you'll have to pull the cover off the rear diff and check the ring gear.

 

It's a 98. It has the sticker on the box. I just don't know the codes.

 

Last time I took the diff cover off I wasn't sure of the numbers on the rings. I'm also not sure if it's stock but I think the only thing done was a 6 inch lift.

 

The ring gear will be stamped with two numbers. Say 37 and 9. These are the number of teeth on the ring and pinion gears. 37 divided by 9=4.11 gears.

Rpo codes are available many places online. West coast diffs has a good list just for what your looking for. These are the ones I know by heart for rear ends.
Gu4=3:08
Gu5=3:23
Gu6=3:42
Gt5=3:73
Gt6=4:10

 

I was hoping I had 3.73 but I'm thinking they are 3.42 which means I'll be wanting to upgrade them. What would be the best suggested ratio?

 

Most k1500's are 3:42.

It depends on a lot of factors,
What size tires you want to run is most important. That way you know what gears will bring you back to stock "power" . Then go from there depending on what you want to do with the truck.

I'm assuming you are running large tires since you mentioned a lift.

 

It's a 4x4 so yes I'm running 35/12.50/16's. I had 36's and down sized. But of couse I want the power to pull and play pretty much.

 

 

4:56 would probably be the best choice. May want to do 4:10 if it's a daily driver that you want to cruise down the highway with.

You may have limited choices in a 8.25 front diff, but I would think 4:56 would be available.