Another differential question

[Wilma-Colorado]

A Ford truck mechanic told me that to drain the older differentials that have no drain plug you can run a second nut on the bottom center stud, lock them together with two wrenches, and back the stud out of the case. The hole goes clear through and the fluid will drain out. Anyone tried this or know if it works ?

Maybe on the drain-less 3 speed transmissions too ? Pull the bottom center stud for the tailshaft housing ?

Thanks in advance,

Wilma

[basketcase0302]

Wilma,
I do still learn something everyday! I remembered hearing this when I read your post and it looks like the below illustration confirms it. Maybe someone else with a 9" can chime in here as well as I sold my last 9" about two years ago.
Look at part # 4347 stud and it looks like he's right!

[abyars111]

I think it would work. That's a cool trick.

[eggman918]

I looked ta a dissembled 9" in my storeroom and the studs pressed in from the back like wheel studs do

[averagef250]

You thread a nut on and hit it with a hammer. The stud goes in and the oil will flow around the stud, just takes a long time.

[Wilma-Colorado]

Here's another idea a New Ford friend suggested: It's pretty off-the-wall.

Drill a 21/64 inch hole in the bottom of the pumpkin. Move aside as the lube begins pouring out. After it stops dripping run a small magnet into the hole and spin it to catch any drill chips the gear oil didn't flush out. Tap with a 27 tpi pipe tap (tapered threads). Install a pipe plug and re-fill through the filler hole.

Has anyone else ever heard of this ?

Thanks Eggman918 for checking a casting to see for sure.



Wilma

[basketcase0302]

Tap with a 27 tpi pipe tap (tapered threads). Install a pipe plug and re-fill through the filler hole.

I don't think this would work due to how thin the 9" axle case is. I'd welded a threaded reducer bushing into my EB 9" rear axle years ago which was a lot of work just due to getting it clean enough to accept the weld. I had the axle pulled apart too which was the perfect time to do it. Maybe someone else can chime in here about threading the axle like that.

[averagef250]

Tap with a 27 tpi pipe tap (tapered threads). Install a pipe plug and re-fill through the filler hole.

I don't think this would work due to how thin the 9" axle case is. I'd welded a threaded reducer bushing into my EB 9" rear axle years ago which was a lot of work just due to getting it clean enough to accept the weld. I had the axle pulled apart too which was the perfect time to do it. Maybe someone else can chime in here about threading the axle like that.

The housing should be about 10 gauge it would probably hold an 1/8" pipe plug just fine, but no bigger than that. Welding a bung is definitely the way to fly though.

[colnago]

One word: Mityvac. Pretty cool hand pump for fluid transfer. You can get one for under 40 bucks. Pop the tube in the filler hole, pump out the old, and refill with the new. Best of all, no mods to the truck! I still have a Mityvac from my motorcycle days, so I'll be changing the diff fluid when the temps cool down a bit.

Joseph

[TNIceWolf]

I have been looking at this post and I had a question. Knocking a stud out is sometimes a risk of not being able to getting it to seat back. But....if a person had the thing apart anyway couldnt you pop out a stud at the bottom and drill and or tap a hole to accept the proper length and thread of bolt? Wouldnt that create a useable drain point for pretty cheap?

[basshound71]

If you blow the picture up you can see that the stud enters from the inside. Sure was hoping it was true though.

[basketcase0302]

Charlie,
If I understand your question right, that's what I pointed out above that I'd done on my old 76' Bronco and what Dustin is talking about here:

The housing should be about 10 gauge it would probably hold an 1/8" pipe plug just fine, but no bigger than that. Welding a bung is definitely the way to fly though.

It's thin metal at about 10 gauge, (not very thick to tap into). I had the 9" in my EB completely apart, (welded the spider gears) and brazed (way...before mig welding was popular) a brass 1/2" reducer bushing into the bottom of the axle housing for my drain. This was a necessity in South Florida with constant four feet deep water crossings, (as well as hours with an axle under water). Extreme duty stuff, (axle vents ran up into the cab with an air trap so when the cab submerged-the axle never got water).

[ultraranger]

The photo below shows 3 Ford 9-inch rear end housings I have. (left to right) 1957 Ford station wagon large axle bearing housing, 1959 Ford Fairlane small axle bearing housing, 1960 T-Bird large axle bearing housing.

I'm not certain about the late '50s model Ford pickup 9-inch rear ends but in the case of the passenger car 9-inch rears, all '57-'58 models came from the factory with a 3/8 NPT drain plug in the sump of the rear end housing. Some but not all '59 model 9-inch rears had this plug. After 1959 though, Ford stopped putting the drain plugs into the housings.




You can run a hose down into the sump of the housing and suck out the old gear oil, with something like a Mightyvac, but this method is not going to get it all out and you aren't really going to know what was left inside the housing with this method. The only proper way to clean out the housing/sump is to yank the axles & remove the 3rd member. This will give you an unobstructed view into the housing and will allow you to completely clean the housing/sump out, as well as give you the opportunity to see if there are any bits of metal in the sump from differential/gear/bearing wear.

It will also give you the opportunity to check the condition of the ring & driving pinion teeth.

Once you have the axles and 3rd member out, this would be the prime time to add a drain plug by welding a bung to the housing for the drain plug to screw into.

[72BahamaBlue]

Plews 001.JPG

I'll share what happened to me and my (new) '71 F100 today.
I have a Plews brand suction gun. Removed the drain plug, snaked in the small hose and tried to get the fluid out. Not much luck, old fluid was pretty thick and cold. Warm fluid would certainly be easier to extract, not an option for the 71...it's missing an engine (getting one on sunday!).
A few more tries, only got about 1 pint out. left the hose in (it was full of gear oil), removed the gun pointed the other hose end into the drain bucket, and let it sit. 2 days later, fluid had siphoned out on its' own.

While your down there, be sure to remove and clean the vent hose, and the nipple that holds the brake line juction block. The hole in the nipple is pretty small, it might be plugged up, and on 3 of my old trucks, bees/wasps made mud nests in the hose end.

[basketcase0302]

While your down there, be sure to remove and clean the vent hose, and the nipple that holds the brake line junction block. The hole in the nipple is pretty small, it might be plugged up, and on 3 of my old trucks, bees/wasps made mud nests in the hose end.

Very good advice as I've had more than one axle develop leaks due to the vent being clogged. I mounted a small filter onto BC #16 this time when I re-worked the D70 similar to this so I'll never have to worry about dirt daubers again: