I decided to replace the differential fluid on my 1923 touring/pickup today with fresh 600W. I was getting nowhere fast with my suction gun, so I decided to try using the brake bleeder cup attachment on my mityvac, it worked great!
The advantage of the mityvac is that it can pull and hold a good vacuum on the suction hose for as long as it takes to fill the bleeder cup with the old 600W. I drained 3 mityvac cups worth of old fluid out.
Then I hung a funnel with a section of flexible tubing up above the differential and refilled the differential with new 600W that had been warmed up in the microwave.
Thanks Mark. I remember how tough and messy it was to remove the old thick 600w oil using the suction gun when I changed the rear end oil last year. WHAT A NIGHTMARE! While the suction gun is a good quality and adequate for regular oil, the 600w oil is just to thick for the suction gun to remove it. Nice of you to share a better way. Jim Patrick
So Mark, whats next,, Im thinkin 90-140- gear oil
yes no .
I put new 600W back in, maybe next time I'll try the 90-140.
A few months ago, I pulled the rear end out from under a customer's T, separated the driveshaft from the differential, and turned the front side of the diff down over a bucket. I came back to it about 10 minutes later and found NO oil in the bucket, so I figured it was dry.
Au Contraire!!! The diff had lots of old 600w oil in it, but it was too thick to fall out of the rear end. What a mess it was to clean up after I separated the housings. The good news was that everything inside had been well-protected by that coating of sludge.
If its full of old 600W oil that does not want to come out, it probably has Babbitt thrust washers which do need to come out.
I've always wondered why the differential pumpkin doesn't have a drain plug at the bottom.
Thankfully, no, Ted. The 600W that was in there was put in in 2008 when the axle was overhauled. I have receipts plus the word of the restoration shop owner that did the work that the rear axle was completely overhauled and the Babbitt thrust washers were replaced with bronze.
I wondered the same thing Bob. It would make life so much easier.
I post every time I see someone that is rebuilding the rear end to make sure to install a small drain plug. Just think how helpful one would be to drain and check for metal wear in the old oil.
Wish I had thought of it when I did mine.
On the drain plug: Ford did not planning on draining them, it saved 5 cents a car x 15 million.
I followed Gene's advice and added a drain plug to my 16's differential I assembled last weekend. To stay old skool I found a square headed pipe plug, looks factory (even though it isn't)
I changed the 600W in a model A transmission about 3 months ago. Last week I drained it and removed the engine and trans.
It was in a cold garage in Oakland not even close to freezing.
I could hardly turn the pilot shaft by hand.
I would not put that stuff in anything when there is the much better modern stuff available.
No Brainer 101.
If you are going to add a drain plug it would be best to install it during a complete rear end overhaul when the pumpkin halves are taken apart. That is so you don't leave metal shavings from drilling and tapping the hole, in the pumpkin. Since the gear oil is so dern thick, I would recommend a hole at least 1 1/4" in diameter(anyone, please correct me if you don't agree, but please say why). Be sure to use a tapered plug so it does not go in too deep and tap your hole using a tapered tap to allow for this, testing often to be sure you don't tap it too big. Pay close attention to the recommended drill size for the tap you are planning to use and before tapping, be sure the hole plug has the same threads as the tap you are using. Sometimes, if you are using an old tap set, the thread sizes (especially the super fine ones) may be obsolete, so do your research before jumping right in. You only have one chance at this and don't want to muck up your pumpkin. Jim Patrick
I drill a hole right behind the right side third boss for the center bolts, tap it for 1/8 pipe and put a little brass plug in it. Anything that won't drain out of that hole isn't doing any lubricating anyway and if there is a chunk of something inside that plugs up the hole so it won't drain you'd better be pulling the rear end.
I see no problem with drilling and tapping a hole with lube in the rear end. Drill the hole and tap it with the lube running down all over the drill and tap and your hand and arm. There won't be anything inside when you get done. Put a plug in it, fill it with 85-140 and go have fun. Seriously, stick a cheap little plastic funnel over the drill bit to catch the lube that will come out when you get the hole through. It keeps it off the drill and your hands. Let it drain mostly, tap the hole and put a plug in.
I have about 75 rear ends including 68 Ruckstells running around with 1/8 pipe drain plugs in them and haven't had a complaint yet that they won't drain.
I have done as Stan suggested with the rear end still under the car. Most bits come out as you drill/tap the hole, any that go up get caught in the goo. After it's drained some put the plug in and fill with diesel, jack the car up and run it a bit. Drain and repeat. Let it drain sitting flat over night. You should be able to get most of the old oil/grease out. Plug and fill with your choice of rear end lube.
I would recommend you put a halogen light under the rear end and let it sit for half an hour. That gear lube will no longer flow like molasses, and you should be able to pump most of it out.
Then follow Stan's advice and put in a drain plug.