1966 riviera open diff gear oil

[Rafz66riv]

I want to service my 3:08 open diff and I was wondering seeing what gear oil should I use? 
thank you 

[JZRIV]

Any name brand, Valvoline, Lucas, etc 80-90W gear lube is fine. I'd stick with conventional. Synthetic not necessary

[EmTee]

One thing to note is that for whatever reason, I was unable to obtain the correct differential cover gasket.  I tried three different places, including on-line suppliers...  In the end, I wound-up deleting the gasket and using Permatex gasket maker.  Just follow the directions and it will work fine.

[JZRIV]

5 hours ago, EmTee said:

One thing to note is that for whatever reason, I was unable to obtain the correct differential cover gasket.  I tried three different places, including on-line suppliers...  In the end, I wound-up deleting the gasket and using Permatex gasket maker.  Just follow the directions and it will work fine.

Correct Tim I went through same disappointing process years ago - CARS is the only place I ever found correct gasket. But yea if using "The Right Stuff" in place of gasket, it will never leak!

[Seafoam65]

Right on Jason!.........Use of a fiber gasket on a differential is a guaranteed leak. Ditto

on a thermostat housing.

[BrianM]

On 1/1/2023 at 3:39 PM, Seafoam65 said:

Right on Jason!.........Use of a fiber gasket on a differential is a guaranteed leak. Ditto

on a thermostat housing.

See I have always had the exact opposite results specifically with differentials and thermo housings. Every time I use any sort of RTV instead of a gasket or with a gasket it always leaks. Didn't matter if it was right stuff, black, blue, red, grey, or whatever it always leaks. Never had a dry (no goop added) fiber gasket leak on either application until months/years down the road. 

I'm probably the weird one or doing it wrong. hehehehe

 

Edited January 6, 2023 by BrianM (see edit history)

[EmTee]

5 hours ago, BrianM said:

...whatever it always leaks.

The 'trick' is to apply a bead of sealer that completely traces the flange and encircles each bolt hole.  Install the part before the goop skins-over, but only tighten the bolts FINGER TIGHT.  Let it stand per the directions (usually 60 ~ 90 minutes) before tightening to specified torque.  Actually, I prefer to let the part stand over night if possible before final tightening.