C3-Differential Markings- Pictures for reference

[Doug J.]

After removing the differential from my early build '71, #4897, I discovered these markings on the differential pinion flange and wanted to provide picture's for those who, like myself, are trying to keep it original or are restoring it to original. From what I can tell, the diff. has never been out of the car. Markings seem to be Yellow paint on the end of the pinion and some on the pinion nut. A long Pinkish mark on the side of the pinion flange with a Blue daub of paint over the Pink mark. This is all that I could find on the case, if there should be other markings, please let me know.

[Michael G.]

Re: C3-Differential Markings- Pictures for reference

Doug,
My Dec. 71 had the exact same colors and locations as yours. I found nothing on the casing but the sticker indicating the gear ratio. If you are doing the seals, be sure to get familiar with the procedure for the drive yoke. Marking before removal and preload measuring.

[Alan S.]

Re: C3-Differential Markings- Pictures for reference

Hi Doug,
Interesting pictures!!
Thanks for taking the time to post them.
Regards,
Alan

[Doug J.]

Re: C3-Differential Markings- Pictures for reference

Mike,
I intend to mark the flange, the nut, and the end of the pinion all in a line with a small chissel mark, I imagine that this is what you were referring to.

[Michael G.]

Re: C3-Differential Markings- Pictures for reference

Doug.
That is one part of it. It also consists of measuring the force needed to rotate the drive yoke. After the drive yoke is re-installed, the nut (new nut) is tightened to a point that relates to the original force needed to rotate the yoke. There are specs for retightening using original innerds (bearings, spacer, and shims) and different spec for new innerds. I dont have this info with me now, but this was discussed here not too far back. I strongly suggest you obtain the Chassis service manual as this is covered in detail. Overtightening this nut can cause you to have the ring gear contact offset and also shorten the bearings lifespan. One thing to remember is a nice bead of sealant at the splines before the washer and nut are installed. Fluid will bleed out through the splines on the shaft.

[Doug J.]

Re: C3-Differential Markings- Pictures for reference

Mike,
I have a 1971 Chassis Service Manual and will read up on it before I do it.
Thanks for the extra info.

[Michael G.]

Re: C3-Differential Markings- Pictures for reference

Doug,
Be sure to check the archives (a month or so ago) on the rear spring install. Lots of good stuff on how to avoid cracking the differential casing. Especially when using new replacement hardware. Good luck.