Front diff help

[tireman74]

I decided to drain and clean the front diff out tonight and low and behold the plate was still there under an inch of an dirt and oil mix. Cleaned off to see the numbers but don't know what they mean. Can someone help?
Also what is the best way to clean the old gasket off the diff and cover?

 

[CJ007]

49 is number of the ring teeth and 18 the number on the pinion gear. 49/18=2.72 gear ratio. Not sure of the other. Maybe axle code/serial #.

 

[tireman74]

So there is 49 on the ring and 18 on the pinion? And the 2.72 is the ratio. I didn't realize that was a dot between the 2 and 72, just thought it was a spot of rust I didn't get cleaned off. Thanks for the help!!

 

[CJ007]

That's the base gearing for the years we have. Not sure how much you know but basically its 2.72 turns of the drive shaft to turn the tires once.

I off road a lot so I changed my gears to 4.56 to improve crawl ratio.