65 Dart GT with older 8.25" posi rear. Gear oil / Limited Slip additive

[WhoDarted]

Hello everyone!
I've inherited my dad's old 1965 Dart GT. It was a neglected restomod 20 years ago and I'm trying to get it back in driver shape. It was an original 273 2 barrel / 904 automatic car but the current engine is a later 360 4 barrel. The 904 was built out (from what I remember) and it has an 8.25" 10-bolt positrac rear. The rear diff cover doesn't have a drain plug. I was going to change out the rear diff fluid but want to know if I need to do anything special for this rear-end? I was going to use 2 quarts of 80-90 oil but wonder if I need to get anything special since it's a posi? Also, should I fill the rear up to the fill plug (passenger side on pig) or is there a better way of knowing how much fluid I should put in? I have almost no experience with Mopar so any advice appreciated.

Thanks!

 

[69FBCuda]

You need to pop the cover to see if it has clutches or cones to determine a requirement for Sure-Grip additive. Fluid should just start running out the fill hole wit the car on level ground.

Knock knock.....
Who's there? ....
Who!..
Who who?

Great there's a bird in the house.

 

[WhoDarted]

You need to pop the cover to see if it has clutches or cones to determine a requirement for Sure-Grip additive. Fluid should just start running out the fill hole wit the car on level ground.

Knock knock..... Who's there? ....Who!.. Who who?


Great there's a bird in the house.

Thank you! I'll know later today.

 

[WhoDarted]

You need to pop the cover to see if it has clutches or cones to determine a requirement for Sure-Grip additive. Fluid should just start running out the fill hole wit the car on level ground.

Knock knock.....
Who's there? ....
Who!..
Who who?

Great there's a bird in the house.

Ok, It's a clutch type so I got the additive. I put in 2 quarts of 80-90 oil, 4 ounces of additive and it wasn't full. So I've now added another 1/2 quart and it's still not full. I thought these held just over 2 quarts? Am I missing something or just keep adding fluid until it starts dripping out of the fill port?

 

[Demonracer]

Just until it's at the bottom of the fill plug hole.

 

[WhoDarted]

Ok, It's a clutch type so I got the additive. I put in 2 quarts of 80-90 oil, 4 ounces of additive and it wasn't full. So I've now added another 1/2 quart and it's still not full. I thought these held just over 2 quarts? Am I missing something or just keep adding fluid until it starts dripping out of the fill port?

It took about 2.75 total quarts to fill it up on level ground.