Differential Newbie - The 1947 - Present Chevrolet & GMC Truck Message Board Network

AZ1970k20 · 06-23-2014, 09:54 AM

Hi Guys,

I just got my first K20 this weekend. I wanted to tackle my first differential gasket change. Sorry if some of my question are elementary. The forum has been great, and I have learned a lot from the other posts on this subject, but still have a couple questions.

1) Looks like there are two holes, one on the front side of the differential and one on the back. What is the difference between the two? I have not pulled them off to look yet, I figure, I would ask first.

2) If it is leaking oil on the side with the axle, what is required to fix that?

Thanks,
Seth

Wrenchbender Ret · 06-23-2014, 10:17 AM

The first arrow points to the ring gear thrust pad adjustment. The second is the fill plug. Neither look to be leaking enough to be concerned about. Remove the fill plug & see if the grease level is up to the bottom of the hole. Unnless the grease looks like it just came out of a can, which it won't, its a good idea to change it. Remove the bottom bolt from the rear cover. The grease will drain out but it may take overnight. Put the bolt back in & fill the housing to the level of the hole with 85/140 GL-5 gear lube. It will take about 3 qts.
Unless it leaves puddles on the floor or runs down the brakes it is not leaking enough to worry about.
_____

AZ1970k20 · 06-23-2014, 10:33 AM

WrenchBender Ret, Thanks for telling me what each of those were. Very helpful. Also love the idea how to drain the diff without pulling it off, very clever. Both were a mess yesterday, I cleaned them up with some de-greaser to see how bad the leak really was. That was one night of leakage. Still nothing to worry about?

Wrenchbender Ret · 06-23-2014, 04:17 PM

I am sorry I made a bad mistake there. I meant to say unless it leaves a puddle or runs into the brakes it is nothing to worry about.

Wrenchbender Ret · 06-23-2014, 04:53 PM

It seems to me you could fill it through the vent. It takes about 4 pints. You could raise the side of the truck that the vent is on so it would flow right into the housing.

Tinkermc · 06-23-2014, 05:52 PM

Welcome to the Forum and we are all glad to answer questions, with pic's is much better.

AZ1970k20 · 06-25-2014, 10:14 AM

Thanks for the welcome and Thanks for all your help.

06-23-2014, 09:54 AM	#1
AZ1970k20 Registered User Join Date: Jun 2014 Location: Scottsdale Az Posts: 6	Differential Newbie Hi Guys, I just got my first K20 this weekend. I wanted to tackle my first differential gasket change. Sorry if some of my question are elementary. The forum has been great, and I have learned a lot from the other posts on this subject, but still have a couple questions. 1) Looks like there are two holes, one on the front side of the differential and one on the back. What is the difference between the two? I have not pulled them off to look yet, I figure, I would ask first. 2) If it is leaking oil on the side with the axle, what is required to fix that? Thanks, Seth Attached Images

06-23-2014, 10:17 AM	#2
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,229	Re: Differential Newbie The first arrow points to the ring gear thrust pad adjustment. The second is the fill plug. Neither look to be leaking enough to be concerned about. Remove the fill plug & see if the grease level is up to the bottom of the hole. Unnless the grease looks like it just came out of a can, which it won't, its a good idea to change it. Remove the bottom bolt from the rear cover. The grease will drain out but it may take overnight. Put the bolt back in & fill the housing to the level of the hole with 85/140 GL-5 gear lube. It will take about 3 qts. Unless it leaves puddles on the floor or runs down the brakes it is not leaking enough to worry about. _____ Last edited by Wrenchbender Ret; 06-23-2014 at 04:20 PM.

06-23-2014, 10:33 AM	#3
AZ1970k20 Registered User Join Date: Jun 2014 Location: Scottsdale Az Posts: 6	Re: Differential Newbie WrenchBender Ret, Thanks for telling me what each of those were. Very helpful. Also love the idea how to drain the diff without pulling it off, very clever. Both were a mess yesterday, I cleaned them up with some de-greaser to see how bad the leak really was. That was one night of leakage. Still nothing to worry about?

06-23-2014, 04:17 PM	#4
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,229	Re: Differential Newbie I am sorry I made a bad mistake there. I meant to say unless it leaves a puddle or runs into the brakes it is nothing to worry about.

06-23-2014, 04:53 PM	#5
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,229	Re: Differential Newbie It seems to me you could fill it through the vent. It takes about 4 pints. You could raise the side of the truck that the vent is on so it would flow right into the housing.

06-23-2014, 05:52 PM	#6
Tinkermc Registered User Join Date: Jul 2011 Location: Farmville, Va Posts: 3,026	Re: Differential Newbie Welcome to the Forum and we are all glad to answer questions, with pic's is much better.

06-25-2014, 10:14 AM	#7
AZ1970k20 Registered User Join Date: Jun 2014 Location: Scottsdale Az Posts: 6	Re: Differential Newbie Thanks for the welcome and Thanks for all your help.



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