# Rear End "C-clip" question



## mrvandermey (Jun 15, 2011)

Hi guys. I just picked up my 12 bolt posi rear end, and of course it does not have any brakes on it. So I went ahead and ordered a disc brake conversion kit for it.

I know in order to remove the current backing plates (left over from the original drum brakes), that I will need to remove the current axels. As I understand it, the axels are held in place with C-clips, but I know nothing about C-Clips. I assume to get to the C-clips I will need to remove the differential cover, is that correct? What do C-clips looks like and where specifically are they? Can they be removed and re-installed by someone like me who is mechanically challenged? Or do they really need a professional's touch?


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## Indecision (Oct 24, 2010)

Just found this pic online... not application specific, but a c-clip retained axle is a c-clip retained axle.

If you're mechanically challenged, I wouldn't attempt it myself... it's not "hard" in a technical way, but it hard in the sense it can be a pain in the ass.


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## chuckha62 (Apr 5, 2010)

You have to remove the cross pin which is held in place with a retaining bolt. Once the cross pin is out of the way, you push the axles in to allow the c clips to clear the spiders. Once the clip is out, remove the axle(s).


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## mrvandermey (Jun 15, 2011)

Okay, thank for the pics, that makes sense on C-clips. Stupid question time, I know there is fluid in differential, how do you fill the differential with fluid? Is there a fill hole or do you put fluid in with cover off?


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## chuckha62 (Apr 5, 2010)

Cover has to be on. The fill plug is on the passenger side front just ahead of the axle tube and above the casting web.


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## rexs73gto (Nov 25, 2012)

The fill plug is a square plug that is on the passenger side of the rear end you will just need an extension & a socket wrench to take it out. When you fill it it needs to be in place on the car so it's sitting where it should. When you fill it you put in the fluid until it starts to run back out of the plug. Start by putting in about 1 Qt. then add the 2nd Qt. slowly until it starts to run back out then your rear end is ull. Put the plug back in. If it's a posi unit don't forget to put in a bottel of the posi-additive.


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## mrvandermey (Jun 15, 2011)

rexs73gto said:


> The fill plug is a square plug that is on the passenger side of the rear end you will just need an extension & a socket wrench to take it out. When you fill it it needs to be in place on the car so it's sitting where it should. When you fill it you put in the fluid until it starts to run back out of the plug. Start by putting in about 1 Qt. then add the 2nd Qt. slowly until it starts to run back out then your rear end is ull. Put the plug back in. If it's a posi unit don't forget to put in a bottel of the posi-additive.


It is a posi and thank you for the heads up, I did not know about the posi-additive.


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## chuckha62 (Apr 5, 2010)

Since this is Chevy 12 bolt, with an Eaton type (presumably) carrier, do NOT use Synthetic gear oil. As for the posi additive, make sure you get the GM made stuff. Ames sells it, but you should be able to go to the dealer and get it cheaper. Check Ames for the GM Part number as it has changed several times over the years.


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## mrvandermey (Jun 15, 2011)

chuckha62 said:


> You have to remove the cross pin which is held in place with a retaining bolt. Once the cross pin is out of the way, you push the axles in to allow the c clips to clear the spiders. Once the clip is out, remove the axle(s).


Hi guys, I am at a loss. I have removed the differential cover and drained the fluid. I carefully rotated the gears to inspect them for obvious damage and so far all looks good (or at least to me, for I do not see broken or damaged teeth on any of the gear and do not see any piece of metal in the differential housing).

I am trying to remove the "C" clips in order to remove the axles so I can do the rear disc brake conversion (currently only the drum brake backing plate is left of the rear drum brakes, everything else taken off by previous owner). I think I found the "cross pin". However, I can not seem to find anything that resembles the retaining bolt. Is it possible that my rear end does not use C Clips?


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## leeklm (Mar 11, 2012)

Since this is your first time, I would do a search on YouTube. You should be able to find a video of someone removing axles from a chevy diff. The process is essentially the same for any 10 bolt or 12 bolt diff. You can search for c-clip and bolt-in style axles, which will help you determine what you have. Or, virtually any chiltons manual or something similar would have the procedure with pics.


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## mrvandermey (Jun 15, 2011)

leeklm said:


> Since this is your first time, I would do a search on YouTube. You should be able to find a video of someone removing axles from a chevy diff. The process is essentially the same for any 10 bolt or 12 bolt diff. You can search for c-clip and bolt-in style axles, which will help you determine what you have. Or, virtually any chiltons manual or something similar would have the procedure with pics.


I have looked on You Tube, and the differentials with "C" clips appear different than mine. For example the opening in the actual differential is smaller on mine than on the ones in the videos, and after inspecting it for nearly an hour, I can not find anything that resembles a retaining bold, definitely not where the videos show them. I also do not see any "S" clips in the gears. 

How would I tell if I have a bolt in axle?


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## 05GTO (Oct 6, 2004)

Mr. V.

Are you sure your rear end is a type-C and not a type-O, can you post a picture of the diff cover?


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## chuckha62 (Apr 5, 2010)

mrvandermey said:


> I have looked on You Tube, and the differentials with "C" clips appear different than mine. For example the opening in the actual differential is smaller on mine than on the ones in the videos, and after inspecting it for nearly an hour, I can not find anything that resembles a retaining bold, definitely not where the videos show them. I also do not see any "S" clips in the gears.
> 
> How would I tell if I have a bolt in axle?


The carrier has a large window and a small window. If you're seeing the small side you're going to have to rotate the carrier (turn the yoke) so that the large window is facing you. The large cross shaft (pin, I called it previously) holds the ends of the axles apart. It should be obvious if you really have a 12 bolt Chevy (which incidentally is NOT determined by the number of bolts holding the cover on, but by the number of bolts holding the ring gear to the carrier).

Can you post a picture of what you have?


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## younggto (Nov 22, 2013)

If there are 12 bolts for the rear cover and 10 ring gear bolts it is an Oldsmobile 12-bolt. These have bolt in axles; this no removable cross pin and this not retaining bolt for it. 


Sent from AutoGuide.com Free App


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## BearGFR (Aug 25, 2008)

I'm going to include two photos. The first is a "Type O" rear axle out of an Oldsmobile that has 12 bolts on the rear cover but only 10 bolts inside attaching the ring gear to the carrier.

The second photo is a "real" GM 12 bolt rear axle.

Which one is the closest match to what you have?

While you're looking at the one you have, count the number of bolts that attach the ring gear to the carrier on yours and let us know how many there are.


Bear


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## ALKYGTO (Mar 29, 2010)

Compare what you have to these- https://www.google.com/search?q=inte...w=1391&bih=627

Pictures of what you have will help us help you. I've build many 12 bolts, Danas, etc. If you have any issues someone here will have the answers.


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