Differential ?? for a 71 C-10 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

JCA1972 · 05-10-2008, 05:00 AM

Ok I consider myself a pretty good shade tree mechanic but I have never changed out the oil from a differential, I need to change out the oil in my 71 C-10, can someone please give me some advice on how to change it out and how to re fill it.
Thanks.

Longhorn Man · 05-10-2008, 06:10 AM

place shallow pan under diff
loosen all bolts on cover, while not removing them. Start at the bottom and work your way to the top
insert screwdriver or rigid putty knife inbetween cover and diff
cuss and wipe smelly oil off of screwdriver/scraper and hand
Once it is done barfing the offending odor/oil, remove bolts and cover.
Scrape oil soaked gasket off diff and cover
wipe out the bottom of the diff with a rag *NOT WITH YOUR FINGERS* there may be sharp metal in there.
install gasket, or real good sealant (I recomend no gasket, and use The Right Stuff sealant) on cover, let sealant tack up good if you went that route
Install cover, remembering the bolt in the one O'clock position gets the bracket with the brake line in it.
On the front side of the diff, passenger side towards the center, just below the webbing that is 1/2 way up, chissel through the caked on crap, and you'll see a pipe plug with a 3/8 inch square recessed area. Put a 3/8 inch drive 6 or so inch extention in there, and remove the plug.
Fill with desired gear oil. 80/90 conventional, or the prefered, but expensive synthetic 75/140 untill it dribbles out the fill plug.
replace plug and clean up your mess.

chrislehr · 05-10-2008, 06:25 AM

Thanks Longhorn - I need to suck it up and do this sometime VERY soon. Recommended place to get the sealant? Any ole Vatozone?

Longhorn Man · 05-10-2008, 01:15 PM

I dunno if they would have The Right Stuff... I get 99% of my stuff from NAPA. It's real easy to get real lazy... they'll deliver it to me and place it on my tool box.

JCA1972 · 05-10-2008, 04:17 PM

Thanks Mr Longhorn Man, thats just what I needed, is that little hose on top of the differential a vent? Mine is plugged. I'll have to replace it.

**steelhorse** · 05-10-2008, 04:54 PM

Yes it is a vent.It should be a hose with a little "vent cap"on it.

whatnow123 · 05-10-2008, 06:19 PM

Quote:

Originally Posted by chrislehr

Thanks Longhorn - I need to suck it up and do this sometime VERY soon. Recommended place to get the sealant? Any ole Vatozone?

You are making it sound like there is an issue back there. Just an FYI, but if your rear is making noise, changing the oil won't fix this... ask me how I know...

chrislehr · 05-11-2008, 02:21 AM

Quote:

Originally Posted by whatnow123

You are making it sound like there is an issue back there. Just an FYI, but if your rear is making noise, changing the oil won't fix this... ask me how I know...

lol - no mine just has a slow leak so it looks like Molly wet herself.

Longhorn Man · 05-10-2008, 11:54 PM

I was thinking that was the brake line T fitting... it's been a while since I did this.

05-10-2008, 05:00 AM	#1
JCA1972 Registered User Join Date: Dec 2006 Location: Baytown, Texas Posts: 194	Differential ?? for a 71 C-10 Ok I consider myself a pretty good shade tree mechanic but I have never changed out the oil from a differential, I need to change out the oil in my 71 C-10, can someone please give me some advice on how to change it out and how to re fill it. Thanks. __________________ 1971 C-10 2004 Yukon: 1998 Honda Accord 2008 Honda Civic 2004 HD V-Rod http://67-72chevytrucks.com/vboard/s...d.php?t=226458

05-10-2008, 06:10 AM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Differential ?? for a 71 C-10 place shallow pan under diff loosen all bolts on cover, while not removing them. Start at the bottom and work your way to the top insert screwdriver or rigid putty knife inbetween cover and diff cuss and wipe smelly oil off of screwdriver/scraper and hand Once it is done barfing the offending odor/oil, remove bolts and cover. Scrape oil soaked gasket off diff and cover wipe out the bottom of the diff with a rag NOT WITH YOUR FINGERS there may be sharp metal in there. install gasket, or real good sealant (I recomend no gasket, and use The Right Stuff sealant) on cover, let sealant tack up good if you went that route Install cover, remembering the bolt in the one O'clock position gets the bracket with the brake line in it. On the front side of the diff, passenger side towards the center, just below the webbing that is 1/2 way up, chissel through the caked on crap, and you'll see a pipe plug with a 3/8 inch square recessed area. Put a 3/8 inch drive 6 or so inch extention in there, and remove the plug. Fill with desired gear oil. 80/90 conventional, or the prefered, but expensive synthetic 75/140 untill it dribbles out the fill plug. replace plug and clean up your mess. Last edited by Longhorn Man; 05-10-2008 at 06:10 AM.

05-10-2008, 06:25 AM	#3
chrislehr Engine n00b Join Date: Feb 2008 Location: Austin Posts: 1,031	Re: Differential ?? for a 71 C-10 Thanks Longhorn - I need to suck it up and do this sometime VERY soon. Recommended place to get the sealant? Any ole Vatozone?

05-10-2008, 01:15 PM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Differential ?? for a 71 C-10 I dunno if they would have The Right Stuff... I get 99% of my stuff from NAPA. It's real easy to get real lazy... they'll deliver it to me and place it on my tool box.

05-10-2008, 04:17 PM	#5
JCA1972 Registered User Join Date: Dec 2006 Location: Baytown, Texas Posts: 194	Re: Differential ?? for a 71 C-10 Thanks Mr Longhorn Man, thats just what I needed, is that little hose on top of the differential a vent? Mine is plugged. I'll have to replace it. __________________ 1971 C-10 2004 Yukon: 1998 Honda Accord 2008 Honda Civic 2004 HD V-Rod http://67-72chevytrucks.com/vboard/s...d.php?t=226458

05-10-2008, 04:54 PM	#6
steelhorse Senior Member Join Date: Apr 2008 Location: Franklinton NC Posts: 1,309	Re: Differential ?? for a 71 C-10 Yes it is a vent.It should be a hose with a little "vent cap"on it.

05-10-2008, 11:54 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Differential ?? for a 71 C-10 I was thinking that was the brake line T fitting... it's been a while since I did this.



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