[camaromaniac]

My friend who is mechanically inclined, but whom had never worked on a rear end before just installed an Eaton Posi with 3.73 gears into my stock 12 bolt rear end and you guessed it--------- in the less than 10 test miles I now have a nice howl. What is the most likely cause, what is the fix and is it now best to leave it to the professionals?

 

[Steiner]

I think if you look deep within your soul you already know the answer, Charlie.

 

[67Rally]

Did you add posi fluid to the rear?

 

[camaromaniac]

Did you add posi fluid to the rear?

MasterPro Chemicals GL-5 80W-90 Gear Oil "High Performance Extremen Pressure Gear Lubricant". Made in the USA. Says it's good for both Limited Slip and Positive Traction rear axels.

 

[big gear head]

Oil doesn't cause this kind of noise. I would guess that he either didn't get the bearing preload set correctly or the pinion depth is off. DON'T DRIVE IT LIKE THIS.

Only use the GM limited slip oil additive in the Eaton Posi. Don't use auto parts store stuff.

 

[Steptoe]

My friend who is mechanically inclined, but whom had never worked on a rear end before

After 40 odd years the only things I do not do are
Set up a diff.
Put in hood lining
Set the front and rear windscreens in place.. thu sure could do so now...next time.
The engine and head machining and balancing.

And ALL of these I leave to a professional that has a proven long term reputation by ppl I know personally over many decades.

A "howl" not a slight whine... thats not even close to tolerance setup.

And regardless of correct limited slip oil or not, it should not howl or even have a slight whine.....
If not LS oil u will get clacking when in turns... doesnt effect a misaligned gears

 

[boodlefoof]

Does the howl change with the level of acceleration/deceleration? If so, my guess is going to be the pinion bearing.

 

[camaromaniac]

Thanks guys. My mistake allowing my friend to stretch out of his knowledge level on such a fine tuned piece of machinery. I just talked with a real Pro and will be delivering the car to him on my trailer to go through the rear end.