!960 differential specifications

[Rodney R.]

I'm looking for set-up information for my 1960's differential. I have a non-posi rear end part # 3725899 that has cast GM12 and K 7 6 markings. I need to know the allowable range for the pinion pre-load and the ring gear backlash.
I have not found any service / repair guides for a non-posi rear end. Is there such a manual available?
Thanks in advance for any help.

[Ray K.]

Rodney,

The differential information you are seeking is available in the the 1956-62 Corvette Servicing guide ST12. Go to section 4 - rear Suspension and Driveline.

Ray

[Gary C.]

Rodney,

ST12 Specifications 14-2 for Section Driveline shows the following, but does not state if Posi or non Posi:
Axle Companion Flange ................. 150-190
Ring Gear to Case . . . . . . . . . . . . . . . . . . . . . . 40-60
Differential Bearing Caps . . . . . . . . . . . . . . • 65-80
Pinion Bearing Pre-Load (1956-1962) 20-25 In.-Lbs.
Gear Backlash . . . . . . . . . . . . . .005"-.008" Preferred
Axle Shaft to Spacer Clearance
(1953-1955) . . . . . . . . . . . . . . . . . . . . . . . . .014" Max.
Propeller Shaft U Bolts . . . . . . . . . . . . . . . . . 14-18

Normally the "Markings K 7 6" indicate 10/7/6 could be a replacement gear dated 1966 ?

Gary
....

[Tom P.]

Rodney,

----------------------------------------------- but does not state if Posi or non Posi:

Gary
....

All the specs for posi and non-posi will be the same.

[Rodney R.]

Thanks all for the responses. This started with a leak around the pinion seal and trying to come up with a game plan to fix it. This lead to a check for the condition of the differential gears and bearings given I haven't look at them in the 50 years that I have owned the car. The car was originally drag raced and I knew the engine was not original to the car but I hadnt realized the diff was not original. My knowledge of differentials could fit on the head of a pin so hence the request and my continuing study. The pinion preload currently is 0 and the backlash is .018'" which I now know is incorrect. All the gear teeth (pinion, ring, spider) seem ok; that is no chipping, breakage etc. but how best to evaluate the gears and bearings? Is it better to replace the bearings any way or should I just set the preload and then adjust the backlash accordingly?
Now that Ive got everything a part I am changing the axle bearings and will be replacing the pinion seal (which started this whole adventure).
Thanks again for your input.

[Rod K.]

Believe your 3725899 casting number would be the cast diff housing from a '57 per the '56-'57 Judging Guide, making the "K 7 6" date code Oct 7, 1956, all of which I wouldn't expect would change the set up specs as '56-'62 should all be the same. Sure Tom P can verify or correct as needed.