336 Posi

[Jim S.]

just drained my oil out and getting ready to refil - however can't find anything advising which gear oil to use along with how much and should one use a natural or synthetic blend and how much additive to use? Thanks Jim

[Gary R.]

Re: 336 Posi

I use only Lucas 85-140 gear oil with 1 bottle of GM additive. You could use 90 wt as well if you like. I never use a synthetic gear oil but there are plenty out there that swear by it.

[Michael F.]

Re: 336 Posi

90 wt gear oil. Be sure you use GM posi additive. Fill to the edge of the fill hole.

[Paul H.]

Re: 336 Posi

I've been using 80/90 gear weight oil and 1 4 oz bottle of GM posi lube for 40 years and have never had any rear end problems. Do some figure eights to work it into the clutches.

[Duke W.]

Re: 336 Posi

The original Mil-L-2105 spec from the sixties was replaced by SAE 80W-90 GL-5, which is commonly available in parts stores. Brand is not important - just the spec.

One bottle of Positraction additive will probably be enough to prevent chatter, but if it occurs add another half bottle.

Don't fill the axle quite full to the bottom of the plug at first. Leave about a quarter inch free space.

"Full" is to the bottom of the plug HOT, not cold. Once you have a sufficient amount of Positraction additive you can then fill the axle to the bottom of the hole when the oil is hot.

The nominal specified capacity is 3.7 pints.

Duke

[Jim S.]

Re: 336 Posi

I use only Lucas 85-140 gear oil with 1 bottle of GM additive. You could use 90 wt as well if you like. I never use a synthetic gear oil but there are plenty out there that swear by it.

Gary - thanks for the input - it has just been so confusing - i wanted the GM products but can not find the oil but found the additive. Again thanks Jim

[Jim S.]

Re: 336 Posi

90 wt gear oil. Be sure you use GM posi additive. Fill to the edge of the fill hole.

As for you also - Michael - Thanks for the input - it just got so confusing - I looked for GM gear oil but can not find it - have found the additive - Again thanks - Jim

[Jim S.]

Re: 336 Posi

I've been using 80/90 gear weight oil and 1 4 oz bottle of GM posi lube for 40 years and have never had any rear end problems. Do some figure eights to work it into the clutches.

Duke - Thanks for the input - It has just been so confusing - wanted the GM products but can only find the additive. Again thanks Jim

[Jim S.]

Re: 336 Posi

I've been using 80/90 gear weight oil and 1 4 oz bottle of GM posi lube for 40 years and have never had any rear end problems. Do some figure eights to work it into the clutches.

Paul -thanks for the input - it became so confusing and wanted the right stuff and only could find the additive. Again thanks Jim

By now everyone can see i am new at this stuff because i answered everyone seperately THANKS to ALL Jim