Friction modifier?

[Frankenchevy]

the p/n in the service announcement seems to be out of date? anyone else find that when searching? is p/n 9986285 the new equivalent?

 

[Rusty Nail]

I always used posi additive in my SS.
It makes the lube "climb" the gears, right? Should function the same in an open rear BUT! I'm almost positive that most all GL-5 today already has it so the point is MOOT.

A better use of energy is to find the leak and fix it but it's likely too late. Best to keep a closer eye in the future.

 

[hatzie]

the p/n in the service announcement seems to be out of date? anyone else find that when searching? is p/n 9986285 the new equivalent?

Not unheard of to have part numbers superseded. The 1994 TSB text in my post was just a cut n paste job.

I always used posi additive in my SS.
It makes the lube "climb" the gears, right? Should function the same in an open rear BUT! I'm almost positive that most all GL-5 today already has it so the point is MOOT.

A better use of energy is to find the leak and fix it but it's likely too late. Best to keep a closer eye in the future.

The SS option package prolly included a "posi" axle... limited slip...

Bad part about gears is they will wear to each other and any further adjustment will make more noise and speed up the demise of your gear set. Best course of action for a daily would be to replace them.

Agreed. If it's not a gear set the OP installed less than 50 miles ago it's done for. It'll howl til it dies. I neglected to point that out. Any life you get from it now is a gift. Use it wisely. ;-)

 

[ThisOldK10]

The sawdust and banana "trick" has been around decades.. It's something used car lots did to quiet howling rearends. The theory is the sawdust particles and banana fibers form a cushion between the gears.. It sometimes works but most time it doesn't.. At best, it's a short term fix but not something I'd ever recommend..

The howling and/or whining the OP is experiencing is probably due to wear.. If the differential was recently overhauled and "set up" improperly, correcting pinion depth and gear backlash might eliminate the noise.. More than likely, the gear pattern has "taken a set" and the noise can't be eliminated without a major overhaul.. Personally, if the whine isn't very loud I wouldn't worry about it...

In my younger days I had a '55 Chevrolet that I did some drag racing with.. The differential was a 5:13 ratio.. The ring and pinion weren't a matched set but had a decent gear pattern.. The thing howled like a banshee during mating season.. Never gave me a bit of trouble..

I am NOT putting sawdust in there, lol. Yeah the howl isn't bad, it's pretty quiet. I have had vehicles that sounded way worse and lasted quite a while (until I eventually sold them) so I am not particularly worried but I am a man on a budget and this is my daily driver so I need to be careful or I will be walking 8 miles to and from work each day.

Also, thank you @hatzie for that information up there.

 

[DoubleDingo]

Be careful...
Limited slip additive is for Positrac diffs like you find in cars. It won't do a thing for a regular open diff.
If you have a truck with the G80 Gov Loc option this will get you in real trouble. GM released a TSB specifically stating that you do not use limited slip additive with the G80 optioned axles and why not to......

Good info, thanks.

 

[idahovette]

Just saw this thread and RustyPile is right ,it HAS been around for decades(so have I). I put bananas in my 56 210 trying to get rid of the noise. Got BIG bananas had a heck of a time stuffing them in the fill hole of that 56 finally figured out if I sliced they would go. I was 16 ,not bright. Worked for a while but with the smell you thought you were at a zoo in the monkey cage

 

[shiftpro]

Geez the best I could come up with was sand in the vaseline...

 

[theblindchicken]

And I was thinking the solution was to add louder exhaust or just remove it entirely

 

[Rusty Nail]

Geez the best I could come up with was sand in the vaseline...

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