im going to look at a d30 out of a 89 yj. will this work for my sas on my truck? also, anything i should look for when im checkin this out? and the guy is 95% sure its got 4.10's in it, how do i tell if it doesnt have a tag?

 

A d30 should work but they can be very weak.
Pull the cover off and count the teeth on the ring gear and on the pinion gear and divide them. That should give you your gear ratio

 

which ones the ring teeth and which is the pinion?
and im just getting this to get the build started. ill either get crrmo shafts later or a 44

 

Ring gear is the large main gear. Pinion is the gear coming from the input of the drive shaft where the yoke is in the front of the diff

 

it seems like you cant get your hands back there to count lol

 

You can see it with the diff cover off... All you have to do is turn the yoke and count the teeth as they go by...

 

there is anther way and easier to check. make a mark on the pinion flange(were the drive shaft bolts up) and mark a stud on the hub(put it at the 12 o'clock position) then rotate the pinion and count the turns on the pinion to the 1 turn on the hub/stud. im gonna guess that they are probly 3.55's or 3.73s

 

Yes it would work but, it's Possible it's one of the vacuum actuated bastards. - never know if it's engaged or not. If you want to use it it's best to find one of the kits to make it a manual engage / disengage.
If it has a tag still write it down I still have axle codes for the jeeps on the computer.

 

how can i tell if its a vacuum actuated axle? or if its manual?
and how much are those kits?
thanks

 

There will be an out of place looking box on the pass side axle tube, you can't miss it. A pic...



There are cheap ways to do it w/o the kit, such as permanently locking it with a bolt, or getting a one piece shaft from an newer YJ. Look it up on the net, but if at all possible jsut avoid getting the dumb vacuum axle in the first place.


Some how tos.....

Dana 30 Vacuum Disconnect - Jp Magazine

 

hey thanks a lot for the info!

 

what exactly do those wires and hoses attach to?

 

no wires its all vacuum lines...

 

where do they all go?