Differential Oil Replacement

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May 14, 2012 | 10:14 PM

#21

ATIS

Racer

Joined: Mar 2012

Posts: 396

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From: New Bern NC

I just drained and replaced my fluid in the 75. I used Royal Purple 75-90 syn with posi additive already in it. No issues, nice and quiet.

May 15, 2012 | 04:11 AM

#22

Stephen Irons

Burning Brakes

Joined: Jan 2001

Posts: 1,206

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From: Loir Valley Sarthe, France

2025 c3 ('74-'82) of the Year Finalist - Unmodified

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Quote:

Originally Posted by Bond007

What are the correct names for the GM oil products for:
Manual Transmission
Differential
Additive

Thanks

Axle Lubricant GM Part # 89021671 - Two required
Limited Slip Axle Lubricant Additive - GM Part # 1052358 - One required

May 15, 2012 | 12:45 PM

#23

Bond007

Thread Starter

Racer

Joined: Jul 2000

Posts: 416

Likes: 4

From: Iron Mountain,Michigan

Oil

Thanks Everyone

May 15, 2012 | 01:16 PM

#24

Clams Canino

Melting Slicks

Joined: Jun 2009

Posts: 2,343

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From: Anderson SC

Quote:

Originally Posted by ATIS

I just drained and replaced my fluid in the 75. I used Royal Purple 75-90 syn with posi additive already in it. No issues, nice and quiet.

Same here.
Noting louder that you DON'T use the additive in Royal Purple.

-W

May 16, 2012 | 10:12 AM

#25

jim2527

Race Director

Joined: Apr 2003

Posts: 19,348

Likes: 654

From: Tampa, Florida

When I did mine I drained, refilled, drove a few miles, drained again and then refilled. You'd be amazed at how dirty the second drain is.

May 16, 2012 | 10:26 AM

#26

Clams Canino

Melting Slicks

Joined: Jun 2009

Posts: 2,343

Likes: 4

From: Anderson SC

Quote:

Originally Posted by jim2527

When I did mine I drained, refilled, drove a few miles, drained again and then refilled. You'd be amazed at how dirty the second drain is.

I had the cover off mine - cleaned it pretty well inside before refilling.

-W

May 21, 2012 | 02:05 PM

#27

DanielA

Heel & Toe

Joined: Aug 2009

Posts: 20

Likes: 0

I need to add some posi conditioner to my differential. I had the car up on ramps last weekend. It is pretty easy to touch the fill plug, but how can you get a wrench on it? It is a square nut and there does not look to be any room to swing a crescent wrench.

There must be an easy way to do this. Could comeone clue me in?

May 21, 2012 | 02:14 PM

#28

Clams Canino

Melting Slicks

Joined: Jun 2009

Posts: 2,343

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From: Anderson SC

You can us a 4pt or 8pt socket easily enough. Or if lucky you can break it free with a crescent and turn it out by hand. I believe it might have a little taper to it.

-W

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May 23, 2012 | 07:11 PM

#29

travelerbob

Advanced

Joined: Jul 2011

Posts: 89

Likes: 0

From: Toledo Ohio

Diff oil removal

Quote:

Originally Posted by Bond007

Hello Fellow Vetteheads,
While replacing tank etc checked the oil in the differential and noticed it to be very black...how does one get it out ..should it be warm?..what oil and additive do I use to replace?

Thank You in Advance.

I'm not sure whitch co. offers it but there is a kit to add a drain plug to the diff. Template shows where to drill and supplies the drill / tap and plug. Price reasonable. May have to Google it. Sounds better than the sucko job.

May 24, 2012 | 01:06 PM

#30

Super6

Burning Brakes

Joined: Feb 2012

Posts: 925

Likes: 7

Quote:

Originally Posted by Stephen Irons

Axle Lubricant GM Part # 89021671 - Two required
Limited Slip Axle Lubricant Additive - GM Part # 1052358 - One required

When you add these, make sure you put the Limit Slip Axle Lube additive in first. This way the whole contents get in the differential. If you do it the other way around, adding the additive last, the fluid starts to overflow out the opening before all of the additive is in the diff.

The well-known gentlemen from Connecticut, who is one of the premier rebuilders of rears, steering boxes and trailing arms, recommends the GM fluids over the synthetic stuff. FWIW.

May 25, 2012 | 12:16 AM

#31

Ralphbf

Burning Brakes

Joined: Feb 2011

Posts: 849

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From: Woodland California

I am a big fan of synthetic oil and grease.
I used conventional oil and GM limited slip treatment.

Ralph

Jul 18, 2012 | 01:21 PM

#32

C3 Vette Dude

Instructor

Joined: Jul 2012

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What is the wait of the GM fluid and cann it be purchased from a local autoparts store like Autozone?

Jul 18, 2012 | 02:15 PM

#33

Clams Canino

Melting Slicks

Joined: Jun 2009

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From: Anderson SC

Quote:

Originally Posted by C3 Vette Dude

What is the wait of the GM fluid and cann it be purchased from a local autoparts store like Autozone?

Chevy parts counter.

-W

Jul 18, 2012 | 02:40 PM

#34

Ralphbf

Burning Brakes

Joined: Feb 2011

Posts: 849

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From: Woodland California

Quote:

Originally Posted by C3 Vette Dude

What is the wait of the GM fluid and cann it be purchased from a local autoparts store like Autozone?

If the question is "What is the weight of the oil for the rear end ",it's 75/90.

And it's available most any where. The additive is about $10.00 at the dealership.
It should take almost 2 quarts. The additive is 4 ounces.

Ralph

Last edited by Ralphbf; Jul 18, 2012 at 02:42 PM.

Jul 18, 2012 | 03:00 PM

#35

C3 Vette Dude

Instructor

Joined: Jul 2012

Posts: 156

Likes: 0

rear end lude

Quote:

Originally Posted by Ralphbf

Thanks Ralph. Can it be changed without lifting the car. Can I change it in my garage laying on my back or is it to low to the ground.

Jul 18, 2012 | 03:12 PM

#36

Ralphbf

Burning Brakes

Joined: Feb 2011

Posts: 849

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From: Woodland California

You have to get under the car some how.

I like using ramps they are fast, easy and safe.

You will need a 5/8 8 point or 12 point socket, 4 inch extension and a ratchet.

Plug in it the top right rear of the differential.

And you will have to suck out the old stuff and pump in the new.

Some remove the cover, clean out the crud, replace gasket and reinstall the ten bolt cover. No sucking involved that way.

Ralph

Jul 18, 2012 | 03:34 PM

#37

C3 Vette Dude

Instructor

Joined: Jul 2012

Posts: 156

Likes: 0

Quote:

Originally Posted by Ralphbf

Thanks again!

How did you get that picture of your car on the post?

Jul 18, 2012 | 03:43 PM

#38

Ralphbf

Burning Brakes

Joined: Feb 2011

Posts: 849

Likes: 0

From: Woodland California

Quote:

Originally Posted by C3 Vette Dude

Thanks again!

How did you get that picture of your car on the post?

Honestly I fumbled through. It was on my 3rd attempt, and I can't really remember.

R~

Oct 2, 2012 | 06:10 PM

#39

bouvie1

Heel & Toe

Joined: Nov 2011

Posts: 19

Likes: 0

Quote:

Originally Posted by gcusmano74

Another place to put the drain plug is under the bracket that holds the strut rods. Drill and tap 1/4" NPT just far enough to one side that you miss the ring gear. Make the hole on the bracket larger, of course, so you can easily insert/remove the plug..

My question is where do you siphon/fill GM lub/additive. Any pics or location will be appreciated. Thanks bouvie1