I have a noisy pos unit when it gets hot. What additives do you recommend to guieten the chattering friction disk
-
-
Re: Pos additive
I'm currently fighting the same problem. Everyone I've heard recommends the GM additive. -
Re: Pos additive
Additives work great, but usually the first course of action is to change the lube. Generally, that's what the chattering is telling you; "Change Me!"
Current day posi-lubes hold up a lot better than in the old days when the only thing that would cure the chatter was a shot of whale sperm, or was it sperm whale oil?
Stu FoxComment
-
Re: Pos additive
Pre-1970 when whale oil products were outlawed in the U.S., the Positration additive and Type-A ATF had a little whale oil additive in them, but it broke down quickly from heat.
Synthetic alternatives were developed to mitigate wet clutch chatter, and they don't break down as easily.
The name "whale sperm" was attached to the Positraction additive either because of the whale oil or, perhaps, because the price was so dear.
I recommend that Positration axle oil be changed every 30-60K miles. The C2/3 iron axle housing holds 3.7 pints. Use SAE 80W-90 GL-5 gear oil with one four-ounce bottle of additive, but short fill it a few ounces.
Test for a few hundred miles. If there is chatter add another half-bottle of additive. If not, top off the axle (hot) with the GL-5. The less additive the more effective the Positration, so use the minimum additive to prevent chatter.
If you have no maintenance records that state when the axle oil was last changed, then...
DukeComment
-
Re: Pos additive
Harold;
When you say noisy, how noisy is it. I've never experienced the problem on my 63, only in solid axle cars and it would act like a broken rear end; The inner wheel would jump and the thing would emit a large "bang! Bang!" sound. You'd swear it was coming apart! The only thing I can compare to that was we once had a 39 Chevy w/GMC power that we had a welded spider (locked) rear end. It broke loose during a tow home from the strip and made a god awful noise until it froze up. I was using a bumper hitch on my 56 Chevy and it darn near pulled the center section of the bumper off!
I just wondered what it acts like with the independent rear on a Vette. Can't feel good.
Stu FoxComment
-
Re: Pos additive
I have had the popping sound on both of my 67s. The GM rearend lube "posi" lube will cure the sound. Interesting that I had even more dramatic sounds from my C6 rearend. Even the dealer thought it was loose metal. Turned out to be a needed a fluid change, every 12,000 miles as it breaks down.Comment
-
Re: Pos additive
use amsoil in your rear gear as i have never change the amsoil i put in my 1988 silverado in 1988,150,000+ miles and the posi still works great and no noise. after you change the lube make slow large figure "8"s in a parking lot to get the lube in between the posi plates and you will have less problems. GM now has a new lube for the late model vettes that does not require adding the additive.Comment
Comment