Author Topic: What differential do I have?  (Read 1281 times)

Offline Sprinkler-Man

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What differential do I have?
« on: May 27, 2019, 02:48:03 PM »
1980 GMC K10 4wd, 12 bolt corporate. Need to replace the drivers side axle wheel seal.  Axle code tells me itís a open differential with 3.08 gears. Opened up the differential cover and this is what I found.  I canít push the axle in far enough to get the c-clip off. Any ideas?


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Offline Rapid Roy

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Re: What differential do I have?
« Reply #1 on: May 27, 2019, 04:56:26 PM »
Looks to me water has gotten inside somehow. I haven't seen cream colored gear oil. All I have seen is dark colored.
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Offline VileZambonie

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Re: What differential do I have?
« Reply #2 on: May 27, 2019, 05:17:22 PM »
Not an open differential. You need to change that fluid a few times. To remove the axles you need to remove the pinion shaft for the differential gears by removing the pin bolt and sliding the pinion shaft out. Push the axle in, remove the c clip and pull the axle out. try not to rotate the axles while it is apart.
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Offline Sprinkler-Man

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Re: What differential do I have?
« Reply #3 on: May 27, 2019, 05:24:57 PM »
I removed the pinion shaft but still canít get the axles in far enough to remove the c-clip. I have the rear end up in the air and when I spin one tire forward the other spins backwards. Doesnít this mean itís a non limited slip unit?


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Offline Sprinkler-Man

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Re: What differential do I have?
« Reply #4 on: May 27, 2019, 05:57:55 PM »
It appears that I have what is called a GM gov loc posi unit.


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Offline 1967KaiserM715

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Re: What differential do I have?
« Reply #5 on: May 28, 2019, 05:39:15 AM »
Gov-loc differential

Definitely want to change fluid at least 2 times to make sure all water contamination is gone.

Might be a stupid question, but tires and drums are off?

Sometimes due to brake dust, rust and oil, you may need to scrape the visible portion of the axle to get it to slide past the seal.

Once you do get it apart, don't spin anything, as it is possible to spin the gears out of the carrier, and then the Gov-loc assembly will find new homes all over the ground.

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Current Vehicles:1985 GMC K10(Daily) 1991 GMC K2500(Daily) 1975 Beetle(not running) 1985 Mercedes 300D(not running) 1952 M35    1967 M715(not running)
 1986 Chevy K30(under repair)

Offline Sprinkler-Man

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Re: What differential do I have?
« Reply #6 on: May 28, 2019, 05:43:20 AM »
Tires and brake drums are off. I have spun it a few times and nothing has dropped yet but I will try not to do it anymore. I plan on replacing the seal and bearing on both sides. I saw some people gave it a nudge with a hammer so maybe I will try that.


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Online bd

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Re: What differential do I have?
« Reply #7 on: May 28, 2019, 09:37:07 AM »


Looks like someone experienced a catastrophic gear failure at some point.  Once you get it cleaned up, inspect everything closely.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Sprinkler-Man

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Re: What differential do I have?
« Reply #8 on: May 28, 2019, 09:41:54 AM »
I saw all the teeth marks and was wondering the same thing.  Now that I know I have a limited slip, what gear oil should I run? 


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Offline 1967KaiserM715

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Re: What differential do I have?
« Reply #9 on: May 28, 2019, 04:00:16 PM »
I saw all the teeth marks and was wondering the same thing.  Now that I know I have a limited slip, what gear oil should I run? 


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It's not a limited slip, run regular oil, no additives of any kind.

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Current Vehicles:1985 GMC K10(Daily) 1991 GMC K2500(Daily) 1975 Beetle(not running) 1985 Mercedes 300D(not running) 1952 M35    1967 M715(not running)
 1986 Chevy K30(under repair)

Offline 1967KaiserM715

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Re: What differential do I have?
« Reply #10 on: May 28, 2019, 04:02:46 PM »
Tires and brake drums are off. I have spun it a few times and nothing has dropped yet but I will try not to do it anymore. I plan on replacing the seal and bearing on both sides. I saw some people gave it a nudge with a hammer so maybe I will try that.


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It's really only after the axles come out you shouldn't spin it, once the axles are out, they spider gears have a chance to walk out of the carrier.

I would gently tap the axle ends, might just be a small burr hanging up on the spider gears.

Also get a new center pin bolt, too many times I've seen them reused and they fail. They are supposed to only be used once, at least that's how it is described in some of my service manuals.

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« Last Edit: May 28, 2019, 04:04:38 PM by 1967KaiserM715 »
Current Vehicles:1985 GMC K10(Daily) 1991 GMC K2500(Daily) 1975 Beetle(not running) 1985 Mercedes 300D(not running) 1952 M35    1967 M715(not running)
 1986 Chevy K30(under repair)

Offline Sprinkler-Man

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Re: What differential do I have?
« Reply #11 on: May 28, 2019, 10:30:41 PM »
Tapping with the hammer worked on getting the clips out.  The axles are all pitted up where they ride on the bearings. Now I know why the seals are shot. Looks like new rear axles to go with the bearings and seals.


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Offline JohnnyPopper

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Re: What differential do I have?
« Reply #12 on: May 29, 2019, 05:57:27 PM »
Can someone post what a gov loc posi is, and why something that looks so cool isn't in every truck?
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Offline Sprinkler-Man

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Re: What differential do I have?
« Reply #13 on: May 29, 2019, 06:24:17 PM »
Do these look salvageable?


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Online bd

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Re: What differential do I have?
« Reply #14 on: May 29, 2019, 07:10:09 PM »
No.  Replace them.  They will tear up new bearings.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)