identifying a locking diff

[call me jack]

is there any way you can identify a locking diff, just by looking at the case?

[Adrian_Visser]

If you clean the grease off the back right hand corner there should be a tag with a number on it, if there is an S before the number it is an LSD. i.e. a 3.73 lsd diff would read S3.73.

Otherwise if both the outputs or wheels if it's in the car stil spin the same direction when you spin the input or driveshaft it's lsd, if they spin opposite directions it's an open diff.

[call me jack]

thats while look at diff, still in the car, from behind?

[lateracer]

Regardless of whether it's in the car or out, with the brakes off and car in neutral with both wheels in the air, spin one wheel (or the side of the diff that wheel is/should be connected to). If both wheels spin in the same direction, it's an LSD. If they spin in opposite directions, it's an open diff. Ratio numbers should be on the back as mentioned earlier.

[gearheadE30]

A locking diff will also have a large s in a box stamped in white on the case