I noticed I had a rear differential leak yesterday. I got under it today and cleaned it to make sure it wasn't just the plug leaking. I'm sure this is going to seem pretty dumb, but I had no idea that they were using rubber plugs to seal the fill hole.I'm not comfortable with this arrangement. I suppose I would have to change the cover to get a screw in plug. My question is this: Is it worth the time and expense? It just seems to me that if I left it like this, I would have to keep spare rubber plugs around if I ever felt the oil level should be checked.

 

Are you saying that the rubber plug was damaged when you were removing it, and you are now thinking that you would damage the plug every time you checked the fluid level?

 

Rubber plugs are fine. Mine has lasted for years with no leaks.
Don't use a screwdriver to open it up. Always just use your fingers.

Spare rubber plugs are available at any auto parts store.

 

If the plug has been fine for over 20 years, it will continue to be fine. No need to worry about it.

 

I've had rubber and threaded, metal plugs without issue. You would have to go to a junk yard and pull a cover, buy or make a new gasket, drain, and fill the differential. It isn't worth it unless you really hesitate to keep the rubber.

 

That is the only place that has never leaked on my 90 . Well over 300k. Rubber ages, I'd get a new one and your good for few 100k more.

 

I haven't removed it yet. I did just clean off the diff and will drive it a day or two to determine if it is the plug leaking. Again,a rubber plug seems to be a disposable item that once removed needs to be replaced. If they are not a problem this way I will just put another new plug in. Thanks all.

 

Just get a new one and be done with it.

 

I'd be cautious in buying a replacement from any chain auto parts store.

My experience with Chinese rubber auto parts has been uniformly poor.

 

Those plugs should be changed as a part of routine maintenance. I change mine every 17 years whether it's leaking or not.

 

If you're considering grabbing a cover from an older non-clip Dana35 that has a metal plug, just beware that the hole is not in the same place and you'll starve the wheel bearings for oil.

 

You heard the man!

Dave - the service life is 16 years.... you're truly playing with fire my friend!

 

Don' forget to keep the old one so when you get it in your head you want to paint the diff cover you are prepared. LOL.

 

I just had to replace mine. Was only about $5

 

my experience with new rubber vs old has not always been good

imo, take it out, clean everything, if its intact, reinstall, 5min job

if it still leaks, get a new one

dont throw the old one out