Hello all, since my health wont allow me to do all the larger things my mind would like to do, I am doing mini projects. As soon as I get my rear end properly broken in at 500 miles, I plan on another mini project , being drilling and tapping the bottom of my 9". I did much research and have read all about sucking oil out through thee fill hole which at least on mine, I cant get a tube past the gear teeth (I guess it depends on your gear size's), and removing the bottom stud and so forth. I would like something easier as I plan on changing the fluid more often than some. OK I have already purchased a 1/8"-27NPT tap with the suggested drill size and handle, all decent quality no Chinese. I was going to go 1/4" NPT but after seeing how large it was I opted for the 1/8" as it has more threads per inch an will have less effect structurally on the case itself, but is still of sufficient size to drain 90 weight. I realize 1/8"sounds small but after weighing all the factors was my choice. Now after sitting here waiting for the 500 mile mark which seems like forever, I figured I would ask to see what your individual opinions on the subject are. I got a lot from an advanced search, but Im still curious what the current members think. Better now than after right. Thanks .

 

1/8" NPT is nearly 1/2" diameter, plenty big. Can you get a magnetic plug in 1/8"?

 

Just drive for a half hour or longer to warm up the oil and get any particles into suspension before draining. 1/8" NPT is plenty large for the job. Barring contamination (no submarining the axle) changing every couple years should be more than adequate. Be sure to offset the plug to avoid interference with the ring gear.

 

Jim, while I agree wholeheartedly that axles ought to have drain plugs, I've gotta tell you that I have my concerns with adding one to a 9" the way you're planning to. The plug would need to go in the housing, but it's just stamped steel and I fear it will be way to thin to get a pipe thread drain plug to hold and seal in it. I did a little googling and what I found confirmed my suspicions. Many a 9" has had a drain plug added, but all that I found either had an exterior bung welded on for the plug or a nut for it to thread into installed on the inside during assembly. You might want to look into that a bit before you fire up the drill.

 

BOR, excellent points! Not sure I'd weld anything without cleaning out the inside afterwards.

 

Jimmy,
I have added drain holes/plugs in several 9"s and I would not do it the way you are talking. As mentioned already the steel is not that thick to support threading. It may work and hold for a little while but upon going in and out with the plug you are sure to get leaks at some point. There are other ways to do it and as always my lift and welder are here and I am glad to help you with it any time you feel like driving over.

 

I agree with the others about the thinness of the steel in the housing. I added a drain plug in the 9" in my Mustang years ago, as I had thoughts of doing gear swapping for drag racing and street driving. I pirated a drain plug 'nut' from inside an old engine oil pan, tacked that in place at the bottom of the housing, then used the plug that came with it so it works just like changing your engine oil. The steel of the axle housing center isn't much thicker than an oil pan.

 

Well one thing for sure, is that Im glad I asked for opinions. I felt pretty comfortable with the thickness of the housing, but I think its time to for me to take a breath. At least untill I can either get some help manhandling the differential out to do it the right way or paying a local shop to do it. Laying on my back with the 80 lb. differential sitting on my chest trying to line it back up, plus pulling the axles out far enough to disengage doesn't sound like something Im up to these days. Ok another question, is there trick to successfully getting a tube thru the fill hole and past the gear to the bottom? I tried but I didn't try rotating the gears while I tried to get the tube thru. I appreciate each and every opinion I ever get so If you have an idea ,let it fly. Thank you guys for all you input and Dave (Truckeemtnfords) Id take you up on you very generous offer in a hot minute if I could drive that far, but Im afraid I just cant . My DR took me off my Humira for a few months so he can run some kind of new test. This is all good , but it makes even the smallest tasks very painful during this time period. OK enough crying over nothing, but I do appreciate your offer.

 

I went and got a 2 ft. piece of clear tube for mine and cut the tip at an angle. Kinda like when you cut the tip on a tube of caulking. The longer tube helps to turn it some while pushing it through that little hole.

 

Sorry to hear of your pain, Jimmy. You shouldn't need to change your oil for a long, long time, wait till you're in better shape and have nothing better to do.

 

Ross I still have the 90-100 plus L/S additive that I put in for break in after rebuild, shouldn't that come out about 500 miles?

 

Thanks Toby, Ill pick up a couple different sizes of clear tubing and see if cutting it at an angle will work. My gear set is 3.25, do you remember what your running?

 

Jim, I wouldn't sweat it too much if you can't get it changed at 500 miles. Or 1000! Consider for a second how many brand new vehicles roll off the lot with an axle full of oil that doesn't see the light of day again for over 100K miles. As long as you followed the break in procedures for the gears and were careful not to let them overheat during break-in, it'll be fine for a bit. Any gear or bearing material that gets shed will settle in the bottom where it really won't cause an issue anyway. You won't be able to get that material out with a suction tube.

So yes, I'd be thinking about making arrangements to change it, but it is by no means a ticking time bomb. You might consider making a small investment in something like this:
http://http://www.summitracing.com/parts/cur-95070?seid=srese1&gclid=CLiGpfaRm8sCFQKTaQodhSAC5g &ibanner=MobileSwitchNo
And then looking for a good, competent welder with a lift to install it for you. I'd think you could drill a 1/2" hole in the housing, let the oil drain, weld that baby over the hole on the outside, and then refill. A muffler shop might be interested in doing this work for you.

 

Double post.

 

Ok I've heard that it takes the whole village to raise a single boy, and in this case Im the boy. But that's fine with me because I have learned a lot and understood it, from this great thread. And from the # of views I think Im not the only one. I really like the look of the Currie weld in plug assembly, thank you "BOR" for the link, and will probably go in that direction when it's time, but Im not in a rush any more. This has been another example of why FTE is so special. Thank you everyone for your inputs.