Thread: Changing the fluid in a 10 bolt

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I feel like this is the stupid question of the day, but how do I change the fluids on a 1971 10 bolt rearend. My other cars have always had a fill plug.

I have assumed that I would:
1. drain the fluid by removing back cover
2. replace gasket and reinstall cover
3. fill with differential fluid

Here are my questions:
1. should I use a gasket, RTV sealer, or both?
2. Do I put the fluid in through the vent hole? if so, any trick to removing the vent (I think it is a vent)?
3. where can I get a replacement vent.
4. How do I know how much fluid to put back in?

As always I would also appreicate any good advice on this seemingly simple task.

Jay

Remove cover to drain, rtv will work fine to re seal the cover as long as both mating surfaces are clean & oil free. To fill it back up you will find a pipe plug
usually on the passenger side of the front snout, fill it with gear oil till it trickles out of the same hole put the plug back in and your done except for the shower you'll need to remove the smell of gear oil from your body.
I hate the smell of gear oil.

I see Denny beat me to this post by 1 minute.

Not stupid, un-experienced; once ya' done it, you'll know. Drain like you surmised; loosen all the bolts a turn or so, then the lower few some more and pull the bottom of the cover away from the housing to drain. Clean the gasket surfaces on the housing and cover, and generally clean everything up. Now, here is where everyone has their own way of doing things: me, I use a new gasket, flexible gasket sealer like Permatex, or your favorite brand, put a thin coat of sealer on the housing and cover, stick the gasket on the housing and install the cover. Before putting the cover on, make sure that the sealing surface is flat and even; sometimes the bolt holes get "dimpled" and should be flattened back out with a hammer and dolly of some sort - I use the end of a piece of flat bar for a dolly. I also use a couple of studs - 1-1/2 inch long bolts with the heads cut off will work nicely, too - to screw into the housing to hold everything in alignment while I start a few bolts. To re-fill, there is a plug with a square "socket" hole in it on the right front of the housing about where the pinion "snout" flares into the housing; remove it, and fill until the oil level is just below the edge of the hole; oil comes in plastic bottles with a spout and a small hose, or a jug with a pump and hose. Close it up and you're done - except for getting rid of the smell.

Lke I said, everyone has a different way of doing things like this; this is mine.

Thank you.

I knew I was asking the right crowd. I haven't spent enough time under the car so I am guessing that I have simply never noticed the fill hole. Thanks again.

Originally Posted by HWORRELL

Remove cover to drain, rtv will work fine to re seal the cover as long as both mating surfaces are clean & oil free. To fill it back up you will find a pipe plug
usually on the passenger side of the front snout, fill it with gear oil till it trickles out of the same hole put the plug back in and your done except for the shower you'll need to remove the smell of gear oil from your body.
I hate the smell of gear oil.

I love the smell of gear oil in the morning!

Any recommendations on gear oil? Can I use a 3/8 socket to free the pipe plug or do I need to get a special square socket?

I have found that by far, the quickest (albeit not the easiest) way to drain a 10 bolt is just dump the clutch with the right foot firmly pressed to the floor.

Originally Posted by 37 Caddy

Thank you.

I knew I was asking the right crowd. I haven't spent enough time under the car so I am guessing that I have simply never noticed the fill hole. Thanks again.

Don't feel too badly. I changed the rear cover on my Explorer and when I took it to a local service center to have it topped up, the "mechanic" insisted that he had to remove the cover to fill it with oil. He was not aware that there was a filler plug. Now remember, this person regularly changes oil and supposedly checks the fluid level in the differential as a part of that service.

Sump'n weird goin' on here. When I answered the original post, my screen didn't show any other posts, and I thought I was the first one to reply. Looks like I could'a saved my fingers. A lazy man's lament.

Originally Posted by Rrumbler

Sump'n weird goin' on here. When I answered the original post, my screen didn't show any other posts, and I thought I was the first one to reply. Looks like I could'a saved my fingers. A lazy man's lament.

I saw your post. It happens to all of us. So now you can become a member of the club.....LOL!