rear diff lube - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*vegaschevy* · 07-29-2009, 12:48 PM

I am going to change out the rear diff lube on the truck I just picked up. What is everyone finding works great how much and if it is a factory POSI does it need an additive?

**CPNE** · 07-29-2009, 01:02 PM

Some info here

*vegaschevy* · 07-29-2009, 01:06 PM

Quote:

Originally Posted by CPNE

Some info here

thank you, headed to get some 90w oil and some GM additive...

any idea how much goes in it?

**CPNE** · 07-29-2009, 01:13 PM

Quote:

Originally Posted by vegaschevy

thank you, headed to get some 90w oil and some GM additive...

any idea how much goes in it?

approx 2-3 quarts. The instruction on the additive may specify exactly

*vegaschevy* · 07-29-2009, 03:33 PM

Quote:

Originally Posted by CPNE

approx 2-3 quarts. The instruction on the additive may specify exactly

nope, just says one bottle per diff, is there a fill hole on the diff? I guess I could go look. Fill till it comes out?

**CPNE** · 07-29-2009, 03:36 PM

Thats what most people do. I'd put the additive in first obviously. IIRC the fill hole on a 1/2 to is on the passenger side of the diff somewhere. I deal with mostly 3/4 tons which have the fill hole on the diff cover.

gcburdic · 07-29-2009, 04:04 PM

Hey vegaschevy....pick yourself up a Haynes manual too....has lots of good info in there too....BTW, my fill hole was on the passenger front side of the pumpkin....

cdowns · 07-29-2009, 04:41 PM

ROYAL PURPLE no need for additive with it

BCOWANWHEELS · 07-29-2009, 04:47 PM

i run 85-140 amsoil synthetic with gm additive if its a posi. . you,ll never have to change lube again as its good for 250k miles. 90w is too thin IMO. BEEN A MECHANIC FOR 40+YRS.

*vegaschevy* · 07-29-2009, 05:00 PM

Quote:

Originally Posted by BCOWANWHEELS

i run 85-140 amsoil synthetic with gm additive if its a posi. . you,ll never have to change lube again as its good for 250k miles. 90w is too thin IMO. BEEN A MECHANIC FOR 40+YRS.

you couldn't pay me to run ANYTHING with AMsoil junk not even my lawnmower

capev86 · 07-29-2009, 05:04 PM

Mobil 1 and Valvoline make 75 or 80W-90 synthetic gear lube. probably a good idea as the pumpkin gets worked hard and the fluid usually doesn't get changed very often.

when i swap the ho52 in my 72 burb to a 4.10 (has stock 4.57) i will be running super expensive royal purple synthetic gear oil because my truck is going to do a lot of towing over the coming years!

BCOWANWHEELS · 07-29-2009, 08:16 PM

i run amsoil in all my semi trucks for over 20 yrs now without a single problem except its $$$$$$$$

unclewatts · 07-29-2009, 08:49 PM

For what it's worth, I been running the same Amsoil 80wt. gear lube and GM additive in my GM corp. Posi that I put in twenty years ago and no sounds, no problems.

*vegaschevy* · 07-29-2009, 09:19 PM

Quote:

Originally Posted by unclewatts

For what it's worth, I been running the same Amsoil 80wt. gear lube and GM additive in my GM corp. Posi that I put in twenty years ago and no sounds, no problems.

alot of things would work in a diff or a motor for that matter.

however, a multi level marketed product that is endorsed by no one is not something I would run out and purchase. Not to mention most their oils are not approved by many if any companies

07-29-2009, 12:48 PM	#1
vegaschevy Account Suspended Join Date: May 2009 Location: las vegas nv Posts: 1,493	rear diff lube I am going to change out the rear diff lube on the truck I just picked up. What is everyone finding works great how much and if it is a factory POSI does it need an additive? Last edited by vegaschevy; 07-29-2009 at 12:50 PM.

07-29-2009, 01:02 PM	#2
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,662	Re: rear diff lube Some info here __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

07-29-2009, 03:36 PM	#6
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,662	Re: rear diff lube Thats what most people do. I'd put the additive in first obviously. IIRC the fill hole on a 1/2 to is on the passenger side of the diff somewhere. I deal with mostly 3/4 tons which have the fill hole on the diff cover. __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

07-29-2009, 04:04 PM	#7
gcburdic Restoration Virgin! Join Date: Jan 2008 Location: Huntersville, NC Posts: 8,298	Re: rear diff lube Hey vegaschevy....pick yourself up a Haynes manual too....has lots of good info in there too....BTW, my fill hole was on the passenger front side of the pumpkin.... __________________ Geoff with a G 1968 Chevy C10 SWB The Mistress 1972 Custom Deluxe C20 Suburban A Suburban Named Isabella 1966 Ford Mustang Mama's High School Graduation Present

07-29-2009, 04:41 PM	#8
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: rear diff lube ROYAL PURPLE no need for additive with it __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

07-29-2009, 04:47 PM	#9
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: rear diff lube i run 85-140 amsoil synthetic with gm additive if its a posi. . you,ll never have to change lube again as its good for 250k miles. 90w is too thin IMO. BEEN A MECHANIC FOR 40+YRS. __________________ I BELIEVE IN JOHN 3:16

07-29-2009, 05:04 PM	#11
capev86 Registered User Join Date: May 2009 Location: Eliot, Maine Posts: 1,314	Re: rear diff lube Mobil 1 and Valvoline make 75 or 80W-90 synthetic gear lube. probably a good idea as the pumpkin gets worked hard and the fluid usually doesn't get changed very often. when i swap the ho52 in my 72 burb to a 4.10 (has stock 4.57) i will be running super expensive royal purple synthetic gear oil because my truck is going to do a lot of towing over the coming years!

07-29-2009, 08:16 PM	#12
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: rear diff lube i run amsoil in all my semi trucks for over 20 yrs now without a single problem except its $$$$$$$$ __________________ I BELIEVE IN JOHN 3:16

07-29-2009, 08:49 PM	#13
unclewatts 70 Chevrolet=Obsession Join Date: Jun 2009 Location: nice ca Posts: 1,067	Re: rear diff lube For what it's worth, I been running the same Amsoil 80wt. gear lube and GM additive in my GM corp. Posi that I put in twenty years ago and no sounds, no problems. __________________ I'm Just like my truck. Old, Ugly and Grouchy. Except my truck starts easily in the morning and doesn't smoke! IT'S NOT EASY BEING GREEN! -Kermit the frog 1970 Chevrolet C-10 Longbed Stepside : 350, Muncie M20, 3.08 GM corp. positraction Forest green exterior/light green interior(Where all my money goes) 1996 Toyota Corolla (Parts runner)



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