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Anyone tap a drain plug into their 9” rear end?
it would prevent needing to remove the center section going forward.
if so, what size? 1/4” NPT? And where? On the bottom?
Welding on a bung would be a better choice. There's not a lot of metal there to thread for NPT plug. And might as well weld on a filler bung while you're at it. I keep telling myself I'm gonna do that.
I have to ask what are you doing that requires you to drain and fill that 9" often enough to warrant a drain plug install? Why not just pull the check/fill plug on the fwd dvrs side and use a hand pump/drill driven fluid pump to get the old fluid out?
Yea I know 80/90 comes out like molasses in winter and its hard to get all the shavings/mud out the bottom of the diff right? And the 3rd member is a heavy pig to be pulling real often...after you pull the axles ect.
X2 the 9" rear housing material is not really thick enough to get the proper amount of threads cut/tapped into it. If you just have to try it (with the 3rd member still installed), use grease on the drill bit to catch the metal shavings. And run a shop vac right there when you drill.
X100 if you wheel it, you better get a guarded plug/flush fit set up, other wise you can rock smack it and have a real bad day. Also remember to get a magnetic plug.
I’m pulling the center section to replace a gasket and was thinking I could tap a bung while I had everything out. I don’t anticipate needing to change the oil anytime again during my ownership but thought it’d be nice for the next owner.
Already got the nuts and washers off. Wasn’t too hard with an angled pick and a screwdriver. Pulling the axle soon (just got a bottle jack delivered today…truck is up on 4 post lift and jack plate wasn’t big enough for my floor jack)
I’m planning on getting the lube locker gasket. I’ll need new axle flange gasket too?
Well you got lucky then, the copper crush washers can be a PITA sometimes. Yes new flange gaskets AND a slathering of RTV (The Right Stuff) around the inside of the axle tube and or on the outside of the seal before you install it. See below video.
Safety note: Since it is on a 4 post lift, make sure you have a front axle support stand in place (and a rear one also) before you start jacking/pulling/pushing on the 3rd member to get it loose. Also know when you get the 3rd member out that is WEIGHT off the back of it and can cause a CG shift of the vehicle on the 4 post lift. SAfety SAfety.
Pretty good U tube video I can find to show you what I mean about the RTV. 9:18 is the axel seal part.
I did it on a Dana 50 front axle since the cover isn’t accessible and I didn’t think a siphon would be thorough enough.
I removed the fill port, punched the bottom, drilled a small pilot, and drilled it out with a 37/64” bit, being careful not to drill all the way to leave a land for the plug to stop.
I tapped it with a 3/8 NPT tap coated in grease to catch the babbit and held a shop vac as well.
I blew air through the top and flushed with diesel and corked it with a magnetic flush pipe plug with Allen socket.
Back when Ford (maybe was Chevrolet) eliminated the torque converter drain plug, we got a letter to take next time we did a fluid/filter change instructing the mechanic to drill the TC with a certain bit covered in grease, then to tap the hole with a greased tap, and a 1/8-NPT plug was used as a means to drain the TC in the future. I had several Chevies in the mid '80s-'98, but my last three cars from 1998 up to retirement in 2010 were Fords. I know it wasn't the Plymouths before the Chevies.
