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This might help others.
This little project has always given me trouble as I could not get the suction gun tube to the bottom of the gear case.
Today I found a new method, (new to me anyway).
Changing gear oil in muncie M20 four speed.
1. take the suction tube off the suction gun and placed the tube out in the hot sun to soften it up.
2. cut off about 15" of a coat hanger.
3. put the coat hanger inside the nice soft suction tube.
4. bent the coat hanger and tube to about 140* and inserted it into the transmission fill hole.
5. tube and coat hanger go right in to the bottom of the gear case.
6. while holding the suction tube, pull the coat hanger out and leave the suction tube in place.
7. connect the suction tube to the suction gun and draw out the old gear oil.
8. when filled disconnect suction gun from the suction tube and empty gun into waste container.
9. reconnect gun to tube and repeat steps 7 & 8 until gear case is empty.
10. filling is simple, no explanation is necessary
I DO NOT KNOW WHY, BUT UP TO 1970, MUNCIES (except the M22) DID NOT HAVE DRAIN PLUGS!!!!!!!!!!!
On all my Muncies, and customers' Muncies, I install a magnetic drain plug and remove the magnetic donut inside the case. EVERY Muncie case without a drain plug has the boss for installing a drain plug (WHY DIDN'T GM PUT ONE IN??????????????????). It's just too easy to install a drain plug------------even with the transmission in the car (although, the donut magnet cannot be removed).
This is an accumulation of metal particles on the donut magnet in the bottom of a Muncie case. It CANNOT be cleaned off unless the tranny is removed and torn down. But with a magnetic drain plug, when the plug is removed---------------the metal particles come out with it!
This might help others.
This little project has always given me trouble as I could not get the suction gun tube to the bottom of the gear case.
Today I found a new method, (new to me anyway).
Changing gear oil in muncie M20 four speed.
1. took the suction tube off the suction gun and placed the tube out in the hot sun to soften it up.
2. cut off about 15" of a coat hanger.
3. put the coat hanger inside the nice soft suction tube.
4. bent the coat hanger and tube to about 140* and inserted it into the transmission fill hole.
5. tube and coat hanger go right in to the bottom of the gear case.
6. while holding the suction tube, pull the coat hanger out and leave the suction tube in place.
7. connect the suction tube to the suction gun and draw out the old gear oil.
8. when filled disconnect suction gun from the suction tube and empty gun into waste container.
9. reconnect gun to tube and repeat steps 7 & 8 until gear case is empty.
10. filling is simple, no explanation is necessary
Nice trick!
I wonder if surgical tubing would work with your coat hanger. It's really flexible.
If I want to drill and tap the case with it in the car, don't I need to worry about chips getting inside the case?
Not really. Once the drill punches through, the oil will flush out most of the MINIMAL amount of chips which get inside (the drill bit will be pulling out most of them).
As drilling and tapping progress, you can use a long cotton tipped applicator to reach in and pull out chips.
Last, the few chips which MAY get inside will be alum which will be almost a zero issue.
If I want to drill and tap the case with it in the car, don't I need to worry about chips getting inside the case?
Just to add to what DZAUTO suggests. If you line the concave areas of the tap with a heavy grease. The grease will then catch, and hold, a lot of the loose material.
You may need to clean the tap and re-apply the grease a few times.
If you're REALLY ****, you could always drill and tap, then, plug the hole, refill part way with fluid then, let it flush out the rest!
Gary
Last edited by Gary's '66; 06-11-2017 at 12:39 AM.
[QUOTE=DZAUTO;1594918825]I DO NOT KNOW WHY, BUT UP TO 1970, MUNCIES (except the M22) DID NOT HAVE DRAIN PLUGS!!!!!!!!!!!
On all my Muncies, and customers' Muncies, I install a magnetic drain plug and remove the magnetic donut inside the case. EVERY Muncie case without a drain plug has the boss for installing a drain plug (WHY DIDN'T GM PUT ONE IN??????????????????). It's just too easy to install a drain plug------------even with the transmission in the car (although, the donut magnet cannot be removed).
That's a question for the ages. The same could be said for the differential.
My guess would be the bean counters. That and the fact that it would have made less $ for the service department at the dealerships.
I also install a magnetic drain plug in all my rearends.
After drilling and tapping the drain hole, I use a die grinder with a buffing pad to smooth the rough cast surface so that the plug gasket will seal.
The 61-earlier axle housings (62 did not have a drain plug) are stamped steel (NOT thick cast iron) and the threads for the drain plug are few and often have a tendency to strip out. When I have one of the early housings apart, I spot weld in a nut and drill holes through 2-3 of the flats to help the oil drain.
I also install a magnetic drain plug in all my rearends.
After drilling and tapping the drain hole, I use a die grinder with a buffing pad to smooth the rough cast surface so that the plug gasket will seal.
The 61-earlier axle housings (62 did not have a drain plug) are stamped steel (NOT thick cast iron) and the threads for the drain plug are few and often have a tendency to strip out. When I have one of the early housings apart, I spot weld in a nut and drill holes through 2-3 of the flats to help the oil drain.
I swear to God, this is the honest truth, there have been times, and there still are some times, when I would have been willing to go to prison if I could get my hands on some of the engineers who designed some of the dumb stuff that I've seen (and still see) on cars!!!!!!!!!!!!!!!!!!!!
I absolutely cannot believe that some of the engineered features on cars were done by people who have engineering degrees!
Not all, NOTICE I SAID NOT ALL, but WAAAAAAAAY too many engineers have ZERO common sense. During my career as a civilian employee with the USAF, there were some engineers that I just wanted to throw into the intake of a running jet engine!
I just came across this 5 year old thread and it saved my A$$.
I have a typical gear lube hand pump, which worked just fine in the differential, but it wouldn't go into the trans - tube was too thick and too firm. I picked up a foot of smaller gauge tube that fit tightly inside the pump tube, and trimmed the insert end to better slide by the internals. Warmed it up with a hair dryer and it worked like a charm. Also, the advice to leave the tube in the trans and unscrew it from pump to dump the oil is spot on.
Refilling trans is just reversing the same process. Measure out 1.5 gts of gear oil. Fill the pump and push it in =1.5 pump fills. Slow down at the end to detect oil exiting the fill hole. It's all a messy, oily deal.
I first thought I'd follow the additional posts to install a drain plug, and picked a 1/2 thread, 9/16 nut version from NAPA for $3. Then I found the exhaust is in the way, preventing drilling the trans case. So, next year, when I plan to replace exhaust, I'll install the drain plug.
The 61-earlier axle housings (62 did not have a drain plug) are stamped steel (NOT thick cast iron) and the threads for the drain plug are few and often have a tendency to strip out. When I have one of the early housings apart, I spot weld in a nut and drill holes through 2-3 of the flats to help the oil drain. Attachment 48124619
Nice, Tom. Might it be easier to use a castle nut, with the castellations against the housing?
I made my own pump-out systems. Smaller jar for smaller quantities, larger bottle for larger quantities. If the task exceeds the capacity of whichever container I'm using, I just swap in another container that fits the same cap after filling the first one.
MityVac gets a siphon started, and gravity takes it from there. The cap for the smaller container has three hose barbs -- the smallest one for the MityVac, and two different sizes for the fluid extraction tube, depending upon which size fits better into whatever I'm pumping out. Cap off the one that's not being used, then pull a vacuum on the bottle and you're off and running. Makes for easy and very clean pump-outs.
Can you post a picture of this hand pump? I hate replacing oil in a transmission or differential due to the tight access and heavy fluid. Lately I took a 4-qt oil container. Drilled two holes in the cap, inserted a long clear vinyl tube to the bottom with the other end long enough to go into the trans/ diff. Another short vinyl tube was cemented into the cap. I turned my air compressor down to around 3psi, secured an air gun in the short tube and taped down the trigger. The air forces the oil into the item but I need to use a bigger tube as it takes a while to transfer 2-1/2 pints +/- especially with the 90/140 differential lube. But I’m wary as even 2 or 3 psi ballon’s the jug which I have wrapped with bands of Gorilla tape so I’m always looking for something better.
06-10-2017, 03:38 PM
Changing Gear Box Oil in a Muncie
