Differential ID?

[Buick Bruce]

I still can't figure out what diff is in my car (4-speed, 3.36 by counting the turns). Sure would be nice if it's a posi, but guess I'll have to open it up to know for sure?
Any ideas?
Also - last pics show a "PD" paper label with that was on the LR outside frame rail above the axle. Any ideas if this was some kind of factory marking (38,000 mile Fremont car - built 2nd week of Feb)

[Mark Ascher]

Bruce,

Jack up the back of the car and turn the tire. If the other side turns in the same direction = posi. If it's still functioning.
Neat sticker on the frame, I've never seen that.
I also have a 3:36 posi, Fremont car, but didn't have the "LF" mark on the bottom of the axle housing.
I notice yours has the green stripes on the axle tubes.

3:36 was the standard 4 speed rear ratio.

Mark

[Buick Bruce]

I've noticed many photos on this forum with green stripes on rear axle housing - any significance to these markings?

[WkillGS]

Frame label: Used at the assembly plant to ID the frame. My 66 had remnants of one. It was further back just in front of the bumper bracket. From what I've read here, the 65 GS did not share the frame with any other models.

Axle code: I don't see LF listed in the 65 Chassis manual. Could it be a poorly stamped LR.....that would be a 3.36 posi.
The stamped code is hard to make out., but the '357' is the date code= 357th day of the year= Dec 23, 1964.
Posi rears should have an additional stamping. Looks like an 'O' with a 'x' in it.
Both my 65 and 66 have the painted green stripes. Mark, didn't yours have an additional orange stripe?

[Buick Bruce]

Mark - I didn't know I had the "LF" marking on the bottom of the diff. housing until yesterday. I saw some other pics on this site that showed similar marks. I crawled under with a small wire brush and camera and as the rust started going away, the markings started to show up.