Diff gearing & factory LSD's

[rusty1007]

First Question: I know factory LSD's have been touched on extensively in past threads but I wanted to check any way. I got stuck in a thick pile of mud last summer and while spinning my tires I heard a ratcheting noise which from what I have heard indicates a factory LSD.....Correct????. When I jack it up and spin the tires it acts like an open diff and there are no LSD stickers in the glove compartment. I do a fair bit of 4x4ing and have neer heard this noise since??? any idea what it may have been if it wasn't a LSD. I will be opening it up next weekend just to check on things so I will know for sure then.
Second Question: How do I figure out my diff gearing?? can't seem to find anything written anywhere.

Thanks

 

[Yucca-Man]

Look at the ring gear when you open it up. Among other markings will be the tooth count for the ring and pinion; ring/pinion=ratio

No idea what the noise might be, but LSD (limited-slip differentials) are quiet operators. Detroit Lockers are sometimes noisy with ratcheting, but when you jacked up the rear and tried it out, a Detroit would have operated 'correctly' by turning both wheels the same direction.

 

[ChiXJeff]

The only time I'd expect a Trak-Lok to make a ratcheting noise would be when it's either low on oil, or it got filled up without friction modifier. Otherwise, they'll be completely silent.

 

[red87cherokee]

Second Question: How do I figure out my diff gearing??

Another way is to tape a string onto the driveshaft. Roll the Jeep forward exactly one tire rotation. Count how many times the string wrapped around the driveshaft.

3 wraps = 3.07
3.33 wraps = 3.31 (rare, but was an early option)
3.5 wraps = 3.55
3.75 wraps = 3.73
4 wraps = 4.10
4.5 wraps = 4.56
4.75 wraps = 4.88