Sludge in bottom of transmission

[Hartman]

I have just drained my 1961 FFPW transmission and transfer case and have sludge on the bottoms of each. What is the best way to remove that sludge without disassembling the units? I thought about soaking with motor oil and draining before putting clean lubricant in (I have the time to soak these for awhile), but I'm sure somebody with experience out there has a better idea. Thanks in advance....Keith.

[Gordon Maney]

You could put some 5 or 10 weight oil in it and drive it around the block a time or two, then drain it out. Since most is in the bottom, I suspect, you could also pour solvent into the level hole and leave it sit for a few hours, and then drain it out, leaving it time to drain fully.

[Charles Talbert]

If yours is like most we see; the only way to flush will be to disassemble the units so you can access the areas for a thorough clean out. The sludge will have years worth of dirt and fine metal fragments embedded into it. It won't come out without some scrapping and scrubbing. Trying to flush will simply stir up a portion of the fragments. When you pour in the new oil; it's like pouring in oil with sand mixed in; bearings, seals, and gear teeth will suffer.

[JStinson]

Kerosene?

[Charles Talbert]

Problem areas within

A couple more thoughts. If the trans has a PTO on it, the interior bottom of that housing is lower than the trans case, any solvent or flushing fluid that is induced will pool there and can't be removed by draining as there is no plug to do so. Undrained flushing fluid will delute new oil, so that is a bad idea. The same crud that is on the floor of the trans case will also be in this low area of the PTO housing, manual disassembly and clean out is the only way to address the issue.

The transfer case also has 2 other problem areas in addition to the interior bottom of the case. That is in between the bearings within the intermediate gear bore that is in the center of the case. There are passages drilled in the shaft the gear runs on that carries oil to the interior to oil the tapered roller bearings. All the fine junk that is on the bottom of the case and is circulating in that oil drops out of suspension once it is trapped within and between the bearings. We find this stuff that has to be scrapped off the interior surfaces of the gear bore on every one we take down. The build up will eventually plug the shaft oil passages restricting the oil flow, then pending disaster awaits. One other area where the same stuff will be found is on the 2-speed gear on the input shaft. It will be around the splined thrust washer and under the gear teeth that engage the rear gear unit that has the e-brake drum attached. It will be so hard and embedded so well that if you aren't paying particular attention, you will not even notice it is there, will actually look as if it is a machined surface of the gear. It will be impervious to washing, it must be scrapped off with a small sharp object of some sort. This is common on all t/cases; if yours also has the build up in the bottom of the case as it obviously does since that was your concern prompting you to ask the flushing question in the first place, it is a safe bet the stuff I've described here is also in play where you will never see it or remove it without the unit being disassembled and manually cleaned out. It is also typical to find rough bearing surfaces in units where this filth has been in place for a while; due to the fine sediment of dirt and metal that comes from normal wear over time circulating all through the case with the oil doing further damage as it goes. We have built 4 t/cases since January 1 this year; we've seen these issues to some degree in each of them.

[Cheyenne Dave]

[QUOTE=Charles Talbert;86164]A couple more thoughts. If the trans has a PTO on it, the interior bottom of that housing is lower than the trans case, any solvent or flushing fluid that is induced will pool there and can't be removed by draining as there is no plug to do so. Undrained flushing fluid will delute new oil, so that is a bad idea. The same crud that is on the floor of the trans case will also be in this low area of the PTO housing, manual disassembly and clean out is the only way to address the issue.

This is why, on every transmission I service, I have drilled and tapped the P.T.O. case for an allen-driven 1/8" plug. I have used hex head brass plugs, but they can get damaged. Most brass plugs today are hollow and if you knock the head off, your transmission oil supply will drain out. The allen drive plug can be inserted flush with the case, eliminating the chance of damage.

The Dodge Boys allowed several examples of engineering oversight to exist in these trucks, this is just one of them. I see no fault in correcting them, espeially when the remedy is so easy. There is no excuse an incomplete oil change.

[Hartman]

Sludge in bottom of transmission

Thanks to all that have replied and offered advice. Looks like I might have a problem. Will soak with a solvent as best I can and use hand pressure sprayer to try to get solvent above the fill hole (my transmission has no power take off). It's probably too much to hope that because the sludge was soft in the bottom, it will be soft among the gearing etc. This truck hasn't been run much or in a long time. 14,000 on the clock, but that doesn't really translate into anything I guess. I have time to soak and spray and repeat the process as much as I want/need. If I need to have the units rebuilt, I'll cross that bridge when I get there. I also don't have a read on the condition of the clutch. Meanwhile just struggling along.....Keith.

[Charles Talbert]

[QUOTE=Cheyenne Dave;86169]

A couple more thoughts. If the trans has a PTO on it, the interior bottom of that housing is lower than the trans case, any solvent or flushing fluid that is induced will pool there and can't be removed by draining as there is no plug to do so. Undrained flushing fluid will delute new oil, so that is a bad idea. The same crud that is on the floor of the trans case will also be in this low area of the PTO housing, manual disassembly and clean out is the only way to address the issue.

This is why, on every transmission I service, I have drilled and tapped the P.T.O. case for an allen-driven 1/8" plug. I have used hex head brass plugs, but they can get damaged. Most brass plugs today are hollow and if you knock the head off, your transmission oil supply will drain out. The allen drive plug can be inserted flush with the case, eliminating the chance of damage.

The Dodge Boys allowed several examples of engineering oversight to exist in these trucks, this is just one of them. I see no fault in correcting them, espeially when the remedy is so easy. There is no excuse an incomplete oil change.

I agree, we generally add drain plug holes to the casting while they are disassembled; it is then good for future complete liquid draining. However that will do little to relieve a sludge / crud issue that may be already started and in progress of causing more serious issues.

[QuantumJo]

I have to agree with Charles on this one. I think you would be better off letting the "sludge" stay put than stirring up and getting it into everything.

[Hartman]

Sludge in transmission

Thanks to all responding. I am still listening.....Keith.

[Cheyenne Dave]

[QUOTE=Charles Talbert;86171]

I agree, we generally add drain plug holes to the casting while they are disassembled; it is then good for future complete liquid draining. However that will do little to relieve a sludge / crud issue that may be already started and in progress of causing more serious issues.

I was not addressing your crud issue, rather , I was speaking to your observation that the transmission gear oil can not be completely drained.

As to the crud issue, I advocate complete tear down and sercive of every "unknown" driveline component. Flushing is a waste of time and money.