Rear end / axle question

[Crimson Nape]

Let me start by apologizing because I know nothing about the 9" rear end - I typically deal with sports cars and transaxles - but I am trying something new. I am finishing someone else's project (1976 Explorer) and am to the point of actually driving it. As a test, I jacked it up and spun the drivers side wheel and the driveshaft spins. When I spin the passenger side it is "notchy" and doesn't turn the drive shaft. Almost like the drive shaft is just barely too short. Is this normal? I know there are different types of rear ends and I have no idea what this one is. FWIW, I took the passenger side axle out and everything looks new, and I don't want to trash it right off the bat. I also have no idea how much gear oil is in it. I am one of the lucky ones with no drain on the back and no fill plug on the front. I assume the PO filled it thru the axle.

 

[DirtDonk]

You sure there's no little drain plug (sorry, fill/check plug) hidden under some gunk there? Or if there's no gunk, then it's probably just an early design 3rd member. A '76 should have the plug, but it would be in the casting, not the housing.

Sounds like it could be a locker (if you're lucky) or a busted gear or something (if you're unlucky).
When you turn one wheel does the other turn as well? A locker or limited-slip would have the opposite wheel turn in the same direction, while a standard open diff would allow the opposite tire to turn in the opposite direction.

Since when it's notchy it's not spinning the driveshaft, there's a distinct possibility that something is wrong. But it seems to me that you can also get one wheel spinning in an open diff where it does not spin the shaft. But it still shouldn't be notchy.

Definitely check the fluid level somehow. When full, if you pull an axle on level ground you will get gear lube coming out of the housing end.

Paul

 

[hucklburry rev2]

Were both tires off the ground or just one at a time?

 

[Crimson Nape]

There is definitely not a plug and I have both wheels off the ground. The assembly appears to have been rebuilt, or at least taken apart and reassembled. It is clean as a whistle and I can see yellow RTV around the front casing. There is a flat spot on the front casing drivers side where the plug would be, but no plug. And like I said, it is clean, no gunk at all. I see a little gear oil in the axle housing I removed, but nothing runs out. I'll try tilting it this afternoon after church and see what happens.

If i tilt it and nothing comes out, I assume I tilt it enough to get the gear oil to go in (3,4,5 degrees?), and I fill it until it comes out the other side?

 

[DirtDonk]

I don't know if anyone has the difinitive method through the housing end without measuring the fluid, but I would install one axle first, then tilt up a certain amount and wait until it comes out the high side before calling it done.

Or better yet... Tilt it up enough to put 9 pints in it before it flows out.;D
Wait for some others to confirm the amount though, as my Chilton's book shows '66 and '67 being only 4.5 to 5 pints, and a couple of other years being 6 and 6.5 pints respectively.
But most years show 9 pints, so when in doubt put at least 6 in I would say.

What year is yours?

Paul