Any one got any hints on how to get the oil out of the diff without splitting it ?
Use a differential suction pump.
Maybe an oil suction gun? I have one. I can't remember if I used it on mine or not. I've had the diff apart twice already.
Update, Ken beat me to it. Yes, that's the tool I have. It should work well.
(Message edited by 404 not found on May 13, 2015)
If you have a Mityvac, you can use the brake bleeder cup accessory to suck out the old fluid. It's slow and you'll have to empty the cup a few times, but it works.
To refill, try heating the new 600W in the microwave first so that it is easier to pour.
I attached the following nylon fitting to the end of the hose like Ken has up above. Suctions out a bit easier that way.
I drill and tap for a small brass pipe plug, 1/8 inch NPT, while the old oil is still in. Drill the right/passenger side. Most all metal bits will get washed out with oil. Then I put the plug in, fill with diesel or such, with the car jacked up, run for a bit. Drain over night and refill with new fluid.
I don't know why Mr. Ford didn't put a drain plug in the bottom of the differential. _That would have been a simple solution and it would have encouraged more frequent oil changes.
I use a suction pump, which gets most, but not all, of the old oil out of the differential. _At twenty bucks, they're fairly inexpensive. _Follow this link to the unit Lang's offers (and they also carry differential oil):
I've heard some folks tell about how they get rid of the residual oil left behind after suction-pumping by stuffing a soft, absorbent rope into the diff and then pulling the oil-soaked rope out the next day (Common Sense Alert: Do leave one end of the rope hanging out of the differential). _I've never tried that method. _Guess it couldn't hurt.
Lack of drain plugs for differentials and transmissions was pretty common.
Ford Motor Company didn't mention changing differential grease - only adding grease:
What about Lubricating the Differential? Answer No. 103
Do not make the mistake of putting too much grease in the differential housing. The housing should not be more than one-third full. The differential is supplied with the required amount of lubricant when the car leaves the factory. The oil plug should be removed about every 1000 miles and more grease added if necessary. If a fluid grease is used the level should be approximately one and one-half inches below the oil hole.
Can I ask a dumb question? You bet I can!
Why is it necessary to drain the diff oil?
Allan from down under.
By the time the diff grease really needed changing it was likely time for an axle overhaul anyway ;)
That's what I was thinking Allan. We change engine oil due to the heat that damages it and deposits that build up in it. Rear end lubricant, not having those problems, should last indefinitely. JMHO.
The exception is on the TT's. There is a drain plug. It was probably put there to drain out the oil that was full of bronze from the ring gear.
TT differential lubrication per the owners manual:
What about Lubricating the Rear Axle? Answer No. 115
Extreme care must be used in lubricating the differential. An A-1 heavy fluid or semi-fluid oil, such as Mobiloil C or Whittemore's Worm Gear Protective, should be used and carried at a level with the upper oil plug. The differential is supplied with the required amount of lubricant when the truck leaves the factory and the supply should be maintained by replenishments as required. After running the truck about 500 miles, the oil should be drained off by removing the lower oil plug, and the differential filled with fresh lubricant. This operation should be repeated at approximately 1000 miles, and after that whenever necessary. The rear axle outer roller bearings are lubricated by means of dope cups. These cups should be kept filled with a good grade of grease and given a full turn every 100 miles. Before putting the truck back in service after the rear axle has been taken down, fill the differential with oil, jack up the axle and run it for five or ten minutes to insure proper lubrication of all bearings.
I agree. Not that I would like to run 100 year old rear end oil, but once you rebuild it and fill it, it should last longer than you will ever drive it. Henry was counting on that too. He never expected us to be still driving them 100 years later.
Modern ones are the same way. At least some. I had am '81 Mustang that I thought I wanted to drain the manual transmission on. No drain plug. Could you suck it out? Yeah, probably, but no real reason to. No combustion by products to contaminate it.
This is a bargain at 10 bucks, it works well.
Changing oil because it looks metallic and wears out faster if you don't change it.
Thanks all.. to answer the question re Why? ... the car is an original unrestored but operational '26, and Lord only knows how old the rear axle lubricant is. Being in Queensland Australia, a sub tropical climate, it seemed like a prudent thing to do... having said that, the oil is dark grey and quite thick.. much heavier than say 140 grade .. I was unaware that a pump existed to do the job, and made one using a 1 1/2 inch pvc pipe and O ring on a plunger, but the vacuum it creates isn't strong enough to lift the thick oil.. so then comes another question, once the old is extracted what would you recommend I use to refill??
@ Allan Bennett.. appreciate your input.. the Dalgety parts you sent look fine.
I've used 140wt oil for years. It is easily available and has caused no issues.
I think I saw somewhere on the forum that the current 140wt is equivalent to the old 600wt back in the day. perhaps someone more knowledgeable can chime in on that one.
Wonder if you could add some kerosene or mineral spirits to it to thin it, then suck it out? Maybe drive it up and down the driveway a couple of times to mix it?
Hal.. just purchases a couple of litres of Kero ... great minds thinking alike???? Bud .. I couldn't see why 140 would not work, after all I used it for years in my Heavy Truck diffs and it did a lot more miles in harsh conditions in outback Queensland than the old T will ever see. Comforting to get the reassurance however.
If all original, I think the liquid grease/oil of the time was more for the fact to keep it in there, lighter oils would work it's way to the outer bearings, mixing and washing through that grease and leaking past the only form a seal, the felt. A thing to take into consideration Tony if you haven't up-graded to modern seals.
Tony, replacing the oil in an old original is a good idea, if you can! Thinning it makes sense, to make it easier to suck out. Once re-filled with 140, it should not need anything until re-build time.
Hope this helps.
Allan from down under.
A vacuum suction device can be made by using a gallon jug like a pickle jug with a large metal cap. Drill two holes in the top and solder in a couple of copper tubes. Using plastic tubing hook one to vacuum on a engine manifold, the other into the diff,start the engine and suck away. Probably would not hurt to thin a bit.
This was asked on the Facebook page earlier and I'm the one who suggested using the suction gun, and said that it would not be possible to get it all out without splitting the differential.
But I guess people just don't believe it.... lol
William.. Thanks for your response in both forums.. it's not that I didn't believe you, I just like to spread my options.. you never know some one might have a magical solution to a thick solution!!!! The suction gun looks like the best option next to splitting the thing ... might just play with the one I built and try to refine it . Its great to be able to draw on so much expertise that is apparent in these pages.
Of course, there is the issue of Babbitt thrust washers, which require splitting to replace......
The intake manifold is a good source of vacum but the container your drawing a vacum on needs to be substantial or it will collapse.
You all can keep messing around with suction guns or vacuum pumps or drill and tap a simple hole in the bottom of the housing, guess it's your choice.
Mark - You're right on with the suggestion to drill and tap a 1/8" pipe tap into the right side axle half to drain the old oil as you described above. I've done that on one of my T's already and will be doing it on the others.
Thanks Keith! Any rear ends I do, I just drill and tap the hole as part of the rebuild. I have done a couple if in car jobs, it's not like the fluid is going to pour out!
I just pick the car up and turn it over and shake the old oil out!
Don't drill a hole. From the sounds of 'unrestored original' and dark grey oil you may want to open the case and replace a part or 2.
I made a rig out of a mason jar and hooked it up to my shop vac. I used some clear plastic tubing about 1/4" o.d. that goes into the differential through the fill hole. The other end goes into the lid of the canning jar through an appropriate sized hole but located as close to the edge of the lid as practical. I then made a hole in the center of the lid that would accommodate the narrow snout of the hose attachment on my shop vac. The shop vac provides the suction and the mason jar collects the oil.