Synthetic Gear oil??

[SS/GN]

I always used dino in the stock rear of the Buick but have been thinking of a synthetic. What weight and brand are you guys using??Thanks in advance

 

[achalmersman]

I have Valvoline synthetic 75-90 in mine. No extra additive and no chattering yet

 

[Murdock]

I just did mine with Amsoil Severe Gear 75w-90 Synthetic Gear oil ... so far so good. But its only been a week and my tranny finally decided to give up. So that is this weekends plans.

 

[1KWIKSIX]

The instructions for my Auburn Pro Series Posi Differential clearly state not to use synthetic.
Here's the excerpt:

MPORTANT LUBRICANT NOTE-

The Auburn Gear limited-slip differential design has been extensively tested with high quality non-synthetic 80W90 hypoid oils treated with GM or Ford friction additives (3 oz. of additive will treat 1 quart of oil). To avoid differential clutch chatter (noise) and for optimum performance, use the oil and additive described above. Use of other additive and oil types may cause differential clutch chatter.

GM Part Number: 1052358

 

[Nick Micale]

I cannot understand the reasoning behind using an additive or gear oil that will reduce friction on clutches in a limited-slip unit since it is designed to NOT to allow slip?

If "chatter" is present in the unit, it is doing its job.

 

[Chuck Leeper]

Not the same app, but the locker in my 9" says dino only...
Many of these cars go 100K on the original lube... Guess if it's good for that long, why change?

 

[novaderrik]

I cannot understand the reasoning behind using an additive or gear oil that will reduce friction on clutches in a limited-slip unit since it is designed to NOT to allow slip?

If "chatter" is present in the unit, it is doing its job.

the "Chatter" is something that some people don't like in their cars, so they came up with the additive to let the discs slip a little bit.. personally, i think it's kind of cool when one wheel kind of "drags" (for lack of a better term) when turning tight on gravel or a paved surface with a little bit of sand on it..

 

[Venus]

I'ved used Royal Purple in multiple applications and have no complaints at all...great stuff.

 

[SS/GN]

Not the same app, but the locker in my 9" says dino only...
Many of these cars go 100K on the original lube... Guess if it's good for that long, why change?

Chuck I can"t argue with that and I do agree but! I have to use 75/90 in my new truck for warranty and thought if it is this good why not put it in the Buicks. Oil technology has come a long way since 87. For example I went to the Dex 6 in the Buicks because I use it in my other cars and then I only have to keep one type of oil at home on the shelf. Oh and its fun to play in the shop when the wife goes shopping

 

[fastblackracing]

Mobil 1 synthetic rear lube with No additive works well also. /90 weight.

 

[turbo nasty]

Eaton posi says no synthetic as well