1966 Plymouth B Body rear gear lube

I have a 1966 Plymouth Belvedere with a slant 6. The rear end is a 741 case and I noticed a service tag on it so I removed it (see pic). It reads (to the best of my knowledge) "USE-SURE-GRIP-LUBE".

Isn't it most likely that a /6 drive train would not have a sure grip rear end unit? Or did the factory just throw on those tags on all 8-3/4 rear ends?

My main concern is that I want to know what gear oil to put in it because I will be transporting the car via car dolly so the rear tires will be on the road. I want to make sure that the rear end is properly lubed if it requires adding more oil.

Most likely it's a 2.76 ratio but I did not remove the tag yet nor did I see it as I was in a rush when I was under there taking the service tag off.

Thanks in advance.

they could of been ordered with a SG unit or possible its a fleet car of sum kind aka cop ,city light or gas CO and ordered with heavy duty components co post a photo f the fender tag and vin folks will let you know what supposed to be on your car

Regular old gear oil.If its a sure grip a bottle of posi lube avaliable at most parts stores.Rocky

Sure grip was optional. Is it an Auto or manual Trans? Probably a 2.94 if auto. Ford dealer sells good sure grip lube plus 80/90 gear oil

Jack rear end up and spin tires, if both go same direction it is SG, if they go opposite direction th n open.

Do NOT put any synthetic gear lube in that unit
I sold a new posi unit along with two quarts of the proper gear lube and ford posi additive to a local customer, a lawyer, who had a local shop install the it, they used their brand of synthetic gear oil which made the car lurch around corners real badly
Make sure if you need to add any gear oil at all that it is petroleum based only and that is compatible with the sure grip That is absolutely mandatory

racerlall, therocks, NANKET & Cab_Burge Thanks for the helpful hints!!!

Here's an update: The car shows signs of being a former service vehicle. Those signs are it having a radio 10 code cheat sheet on the driver's side sun visor, a coaxial cable under the headliner that lead to the trunk and signs of it being a fleet car via rubber flooring, no radio, no A/C, white in color etc.

The car is an automatic. Just confirmed it is a Sure Grip by doing the wheel spin test. The lug studs are 7/16 and not 1/2 (strange). And the gear ratio tag reads 2.94 (nailed it NANKET).

So WOW a /6 car with sure grip rear end, didn't see that coming.

So in case I need to add gear oil, the Ford brand is what I should use? Is it two part or all in one bottle?

I'm thinking I'll be fine but I want to have a back-up plan in case fluid needs added.

Thanks again guys.

Good deal. It looks original, if so it will be a clutch pedal sure grip.

Sorry I meant use the ford lube for sure grip. Any name brand petroleum based gear oil is fine. I like 80-90 or 85-90, but not the 85-140 weight.

Thanks. So this brand from O'Reilly should work okay? (see pic)

Do I need to add any additives?

Thanks again for your help.

I your going to add a small amount of gear oil your fine with that choice
If your going to drain all the lube out of it and install new gear oil then go to your local Ford dealer and get a bottle of their posi lube additive

Thanks