Hey I'm pretty new to gearing for the drivetrain. I can't seem to find which diff I have so that I can upgrade to some Detroit lockers. Bottom line, which diff came in the 93 ZJ with the 318. Front and rear please.

Thanks in advance for any replies.

 

Your front is a dana 30 the rear might be a dana 35 https://www.cherokeeforum.com/f2/axle-info-148057/

 

Ok good deal. Do you think that the Eaton/Detroit Truetrac's are a quality replacement?

 

Yes they are one of the top of the line units.


As for gearing if the tag has been removed from the cover that shows the gear you can tell by jacking up the rear, placing in neutral and turn the tire one full revolution at the same time someone else watch the drive shaft close to see how many complete turns it makes and then try 1/4 of turns to get close. My guess if an auto 3.55 gear.

 

You can also see if the front diff has a tag. They are both the same ratio. Fred's right though. It's most likely a 3.55 unless it has the tow package, then it's probably a 3.73.

Counting the driveshaft turns doesn't always work because BOTH tires have to turn the same amount or you get involved with the spider gear reduction as well.

 

I belive it has the tow package. So 373 it is. What would be a good choice for axles, and ring and pinion set? Also would it be worth it to upgrade the transmission?

 

That rear Dana 35 is pretty weak, a locker will only add to the possibility of breaking an axle shaft. A swap to the 96 and latter D44a would be a bolt in and a bit stronger. If you can weld and you can swap in a Ford 8.8, it's stronger and has more aftermarket support than the D44a. You would have to purchase a bracket kit for the control arm and spring mounts. The front axle is a low pinion D30. It's an ok axle, but the high pinion D30 from a 96-99 XJ is about 30% stronger. The C's are the weakest link, but can be beefed up with gussets. The ball joints are pretty weak too.