[cranberryredchevelle454]

what do i need to service my 1972 chevelle ten bolt posi rear end? i don’t really know the specs, i just know it has posi and it’s my daily driver so i how the job is easy..... what type of diff fluid should i use? all i need is a new gasket and some fluid right and do i need any other specal tools? i have a factory diff cover so i think i’ll have to take it off the drain it, i’ll clean up the diff cover and repaint it before i reapply it on the housing.

it’s been like this since i got the car but i was told it was normal. my differential wines whenever i press the gas and it gets louder the higher the rpm and the lower the gear the transmission is in.

 

[LaVelle]

They have a lot of different modern lubricants out now for posi rear axles, so it's open for debate.

Originally it came with 80w-90 ( GL5 ) and a posi additive. ( still available over the counter from GM dealers )
Some prefer the F word posi additive over the GM. ( stuff stinks bad, don't get it on you )

Sounds like you have issues that a fluid change won't help.
Find out where the whining is coming from, are you sure it's the rear axle? ( whine changes in different gears )
You could have some bad bearings, or the gears were initially set up incorrectly.

 

[z27]

They have a lot of different modern lubricants out now for posi rear axles, so it's open for debate.

Originally it came with 80w-90 ( GL5 ) and a posi additive. ( still available over the counter from GM dealers )
Some prefer the F word posi additive over the GM. ( stuff stinks bad, don't get it on you )

Sounds like you have issues that a fluid change won't help.
Find out where the whining is coming from, are you sure it's the rear axle? ( whine changes in different gears )
You could have some bad bearings, or the gears were initially set up incorrectly.

If you got noise coming from your rear end on acceleration flushing wont help something is wrong .if its a recent build your gears could be set wrong . on the other hand it could be your rear pinion bearing is gone in any case it needs to come apart remove rear cover and inspect. this job can be done on the ground but very difficult a lift makes it a lot better. when you buy bearings make sure they are Timken first choice or SKF the off shore stuff does not last. hope this helps. Alex

 

[BillyGman]

what do i need to service my 1972 chevelle ten bolt posi rear end? i don’t really know the specs, i just know it has posi and it’s my daily driver so i how the job is easy..... what type of diff fluid should i use? all i need is a new gasket and some fluid right and do i need any other specal tools? i have a factory diff cover so i think i’ll have to take it off the drain it, i’ll clean up the diff cover and repaint it before i reapply it on the housing.

it’s been like this since i got the car but i was told it was normal. my differential wines whenever i press the gas and it gets louder the higher the rpm and the lower the gear the transmission is in.

How many miles have you put on this car since you bought it? If the previous owner performed a ring & pinion gear change less than 1,000 miles ago, and you have noise in the rear end, then there's a good chance he did the job wrong. If the gears were shimmed wrong, and/or he didn't set the back lash to spec, then the rear end could self-destruct within the first 1,000 miles after the work was performed. In extreme cases, the rear axles can lock up on the highway. So if there's a possibility that ring and pinion work was done within the past 1,000 miles or less, I would NOT drive the car anymore if i were you, until you get it fixed.

However, be advised, that some Richmond brand ring and pinion gears ordinarily DO exhibit whining noises, and always will, (it's mostly the 3.90 and numerically higher gears, due to the way they're machined). Do you know what gear ratio you have in the rear? And has the noise been present ever since you bought the car, or did this recently start?

 

[swampy 6x6]

Hi
Diff needs to be dismantled and inspected either damage has happened or is continuing to get worse .
Gm style ""inhousing "" need carefull setting up and always need machined shims. This takes time and patience .
Either the gears are worn and/or setup incorrectly or u have bearings exploding /falling apart.
If the gears are reusable have them lapped in ,=provides a better and quieter gear pattern .
Take diff complete to rear end specialist ...a good one ..

 

[indymanjoel]

May be close to empty as it sits. Drain and fill as you described and see what happens.

 

[boyd66k20]

The whine might just be normal in your rear end. I have an m22 transmission and the whine is normal. Get an opinion from a knowledgeable source before you act.

 

[lucifershammer]

what do i need to service my 1972 chevelle ten bolt posi rear end? i don’t really know the specs, i just know it has posi and it’s my daily driver so i how the job is easy..... what type of diff fluid should i use? all i need is a new gasket and some fluid right and do i need any other specal tools? i have a factory diff cover so i think i’ll have to take it off the drain it, i’ll clean up the diff cover and repaint it before i reapply it on the housing.

it’s been like this since i got the car but i was told it was normal. my differential wines whenever i press the gas and it gets louder the higher the rpm and the lower the gear the transmission is in.

Kyal,

Your last statement confused me, so I wanted to ask something. You mention that it gets "louder the higher the rpm and lower the gear the transmission is in". When you are accelerating at a constant rate and it is whining, and the transmission shifts gears (say from 1st to 2nd), does the whine change frequency (i.e. get lower and then start climbing again?) Or is it a constant whine getting louder and louder regardless of what gear you are in as you accelerate?

Can you post a video of the sound of the whining?

 

[big gear head]

Noise like that from the rear end is not normal and changing the oil isn't going to fix it. Something is wrong with the gears or bearings. My guess is that when the Posi was installed they didn't get it set up correctly.

 

[smitty454]

I just went through this myself. Have less than 2k miles on my 12 bolt rebuild and it started whining. $700 bucks later and its back in action.

Welcome to hot rodding.....

 

[DUTCH MAX HEADWORK]

THREE of these https://www.amazon.com/Valvoline-VV...dchild=1&keywords=80W90&qid=1622572866&sr=8-3 2qts and the 4oz posi lube might get you real close. I always buy 3 to be sure and have some on the shelf.

One of these Amazon.com: Genuine GM Fluid 88900330 Limited Slip Axle Lubricant Additive - 4 oz.: Automotive

A new gasket or just use silicone. A stack of rags.

Change it and SEND IT!

 

[Bob Tiley]

"gets louder the higher the rpm and the lower the gear the transmission is in."

That sounds like a transmission whine not a rear end. Rear End noise will not change with RPM or change with transmission gear.

 

[lucifershammer]

"gets louder the higher the rpm and the lower the gear the transmission is in."

That sounds like a transmission whine not a rear end. Rear End noise will not change with RPM or change with transmission gear.

Yes, that was my possible impression as well and why I asked the question earlier looking for Kyal to clarify that, and also possibly post a video of the noise.

 

[cranberryredchevelle454]

Yes, that was my possible impression as well and why I asked the question earlier looking for Kyal to clarify that, and also possibly post a video of the noise.

i’ll record a video later today on my way home after work

 

[cranberryredchevelle454]

"gets louder the higher the rpm and the lower the gear the transmission is in."

That sounds like a transmission whine not a rear end. Rear End noise will not change with RPM or change with transmission gear.

i don’t know, the shop guy said it was the rear end when we were test driving my car, it also makes a clunking noise when in reverse so.... i’m gonna put the car in storage and wait till next summer to throw my entire life saving into it

 

[cranberryredchevelle454]

"gets louder the higher the rpm and the lower the gear the transmission is in."

That sounds like a transmission whine not a rear end. Rear End noise will not change with RPM or change with transmission gear.

why would it be wining. i couldn’t tell if it was the rear end or the trans but the guy who test drove it said it was the diff

 

[cranberryredchevelle454]

why would it be wining. i couldn’t tell if it was the rear end or the trans but the guy who test drove it said it was the diff

it also shifts hard from park to reverse and then smooth to neutral and then from neutral to drive it shifts hard and vis versa from drive to reverse. it shakes the whole car

 

[Kirk's67SS]

That is the Trany
NOT the Rear End

What Guy Test Drove it ?
What kind of Garage/Shop does he work at ??
How Old is he ???

 

[BillyGman]

That is the Trany
NOT the Rear End

What Guy Test Drove it ?
What kind of Garage/Shop does he work at ??
How Old is he ???

Apparently, the OP likes to ask lots of questions, but doesn't like to answer them.

 

[SFD]

I think he listens, the guy gets busy. He’s done a lot on the car already.