1935 Lincoln transmission flush

[Matt Harwood]

I drained the transmission oil the other day and found this inside:

 

 

It appears to be the result of me putting the wrong oil in it five years ago and driving it a few hundred miles. My question is now that I've discovered the problem and drained the transmission, how do I clean out the rest of this stuff? I'm about to fill it with oil that costs $275/case so I'm not going to fill it and drain it with the good stuff. Any benefit to filling it with, say, diesel fuel and letting it sit for a while? Or some other kind of solvent? I'd like to get it as clean as possible before I pour the expensive oil into it.

 

Any thoughts?

[37_Roadmaster_C]

I am NO expert so take this for what it costs 🙃.  On our old farm tractors the transmission and hydraulic systems share the oil. It was common for us to wait years to long for oil replacement. Often it was after the shift boots had failed and a LOT of water had joined the oil turning into a sloppy yellow mess.  We would drain the oil overnight to get as much as possible out of the case, then we would install the plugs and dump in a good amount of diesel fuel, enough to get everywhere including the hydraulic system pump and cylinders.  We would then run the tractor GENTLY at an idle and engage all gears and hydraulic functions unloaded for  a few minutes, up to 10 or so. Then we would drain again and let it drain overnight again. The next day, fill it up with proper oil and put it back to work for another way to long. Those transmissions are between 45 and 60 years old and have never failed due to oil issues.  Diesel is a very good solvent for oils and still has a lubricating property. Just my experience from years on a farm....

[Ben Bruce aka First Born]

Second what Robin said!   

  

  Ben

[Bloo]

What on earth am I looking at? Is it a water/oil emulsion? Is it metal? What was the "wrong" oil?

 

If that's metal, something is really wrong.

 

Edited April 5, 2023 by Bloo (see edit history)

[Matt Harwood]

57 minutes ago, Bloo said:

What on earth am I looking at? Is it a water/oil emulsion? Is it metal? What was the "wrong" oil?

 

If that's metal, something is really wrong.

 

 

I believe it's both. The oil has turned brown but there are gold flecks in it. I think the water probably got into it when I powerwashed the front end of the car when the engine was out. The gold flecks are probably synchro shavings from running the wrong oil (manual calls for SAE 160, which is today's SAE 250, but I put modern 140 GL4 in it--apparently way too thin). My hope is that I haven't done any serious damage and I don't think I have--it still shifts nicely and is mostly quiet except for a very faint shik-shik-shik sound audible at low speeds through the transmission tower.

 

And if something is really wrong, well, I guess $40,000 worth of fresh engine goes back in the corner with the rest of the cursed car until another time when I save up enough money and energy to take the thing apart again and burn myself to the ground trying to make it work properly. Right now, however, my plan is to clean it out, put the right oil in it, and drive it.

 

If it explodes, it explodes.

[edinmass]

Flush with Diesel two times with tower cover off.........then fill to TOP of trans, let sit for a few hours with HEAT LAMP on it, and then drain....overnight is fine. Watch for fire hazard. After a hot drain then install Diesel AGAIN, and run car up on jack stands and through the gears for say 10 minutes. Then drain overnight again with heat lamp on trans, and then fill with correct oil. I have done this many times, including on both of my White's and the 34 Buick. Works great. Ed

[Bloo]

You didn't do anything bad to the synchros by running thin oil. You could run thinner oil and the synchros would probably love it.

[Matt Harwood]

2 minutes ago, Bloo said:

You didn't do anything bad to the synchros by running thin oil. You could run thinner oil and the synchros would probably love it.

So what are are all the gold flecks? I don't have any other explanation.

 

I changed the oil when I first bought the car and I don't recall seeing anything unusual in the oil at that time. This is most likely a result of whatever I did and driving it about 200 miles with the wrong oil in it. I don't believe any part could have failed just sitting in stasis for 5 years while I did the engine work. I don't have any other explanation. Maybe a bushing coming apart from the thin oil?

[edinmass]

 

I don't think 200 miles with a thinner modern oil would cause any issues. I run Napa gear oil in all our cars...........and it's certainly much less expensive than what you are running.......I'm thinking 140 bucks for five gallons. 

 

 

Best bet if you have concerns is look for a used trans and toss it on the shelf...........cheap insurance. I did it with out V-16...........when the trans went boom, it was great to have a good used unit on hand. And it cut down repair time to a week. On long term keeper cars I always buy spares when I see then at a reasonable price........distributor, generator, starter ,ect.......never been sorry for stuff on the shelf. 

Edited April 5, 2023 by edinmass (see edit history)

[Matt Harwood]

Just now, edinmass said:

 

I don't think 200 miles with a thinner modern oil would cause any issues. I run Napa gear oil in all our cars...........and it's certainly much less expensive than what you are running.......I'm thinking 140 bucks for five gallons. 

 

Any idea what might have happened to create all those metal flecks? I went from having an explanation that didn't scare me to thinking I need to rebuild a transmission on top of everything else.

[edinmass]

Just now, Matt Harwood said:

 

Any idea what might have happened to create all those metal flecks? I went from having an explanation that didn't scare me to thinking I need to rebuild a transmission on top of everything else.

 

Not sure........put the flies on a rag so we can see the actual amount. It may be wash down from when you changed it last time. I think you're going to need to drive it 50 miles and change it again. Then you will have your answer. 

[Bloo]

I don't know, but SAE 140 oil in place of SAE 160 didn't do that. Lots of people have made that substitution. I believe you are correct that SAE 250 is closer to SAE 160 than SAE 140 is. I just don't believe you could have hurt it with that substitution.

 

Maybe some bushing or thrust washer is getting ground up in there. Maybe not. What bothers me is that unexplained noise you said it was making.

 

Synchros are literally friction devices, brakes. They have to cut through and remove the oil film to work. I have been using Redline 75W140NS in the Pontiac. Original was SAE 160. Any wear is going to show up as flakes. If it's minimal, and most of that brass color is really just an oil/water emulsion, maybe there is no big problem.

 

The only reasons I can think of to want super thick oil in a synchromesh transmission are gear noise and or leakage. If the gears were designed around thick oil, they might have too much lash to run quiet in thinner oil. My take is the synchros would be much happier in something really light, like some synchromesh oil, lightweight tractor oil, or motor oil. Basically any oil that does NOT have extreme pressure additives in it, and the lighter the better within reason. The synchros are probably huge if they were meant to run in SAE 160. They had to scrape it off to stop the gears. If you manage to protect them so well that the brass doesn't wear at all, the gears will just grind.

 

When gear oil attacks brass chemically, I believe it turns the brass dark, so that probably didn't happen either.

 

Edited April 5, 2023 by Bloo (see edit history)

[Ben Bruce aka First Born]

3 hours ago, edinmass said:

Flush with Diesel two times with tower cover off.........then fill to TOP of trans, let sit for a few hours with HEAT LAMP on it, and then drain....overnight is fine. Watch for fire hazard. After a hot drain then install Diesel AGAIN, and run car up on jack stands and through the gears for say 10 minutes. Then drain overnight again with heat lamp on trans, and then fill with correct oil. I have done this many times, including on both of my White's and the 34 Buick. Works great. Ed

I don't always agree with Ed but this time I do.

 

[Matt Harwood]

Here's the noise with the engine at idle, the rear wheels off the ground, and transmission in 2nd gear. Noise is the same in all gears and is directly related to driveshaft speed, not engine speed. 

 

 

It sounds exactly like something small being tossed around inside by the gears. I know that can't be what it is, but that's what it sounds like. I'm wondering if it might have something to do with the free-wheeling unit? The lever under the dash doesn't feel very positive in each position, kind of mushy. Maybe it's not all the way disengaged? That's just me being an optimist, I guess. Or a fool.

 

I flushed it twice with diesel fuel, letting it idle in various gears for about 15 minutes each time. It's draining now. I used a paper towel as a filter to catch debris on the first drain and there was very little, although what was there was big enough to see--bigger than grains of sand, not fine like the gold flecks from yesterday. Sticking my finger in the drain hole, there's a low spot in the transmission case below the drain plug that probably won't drain and I could feel a few more chunks of metal there. Not big but not small. The diesel fuel was murky, but I expected that as there was surely still some oil in there. No gold flecks this time.

 

 

I'm going to have to open up the top of the transmission. Usually that's an easy job, but I don't know if you can see it in the video: the E-brake is part of the shifter assembly, so taking the lid off the transmission will be more than just six bolts and lift. But I think that's the next step. I'll tackle that tomorrow or over the weekend.

 

 

Edited April 5, 2023 by Matt Harwood (see edit history)

[Walt G]

10 hours ago, edinmass said:

On long term keeper cars I always buy spares when I see then at a reasonable price........distributor, generator, starter ,ect.......never been sorry for stuff on the shelf. 

You and me both Ed have done that for decades.

[edinmass]

It’s a strange noise, and could be the free wheeling lock up sprag……….they tend to be brass in many cars. Pierce used steel. What ever it is, the transmission needs to come out. Don’t drive it. While it sucks…….it’s gonna be easier and cheaper to deal with it now. 

[Tph479]

There were Lincoln Model k parts listed on Marketplace last week on the east coast. If I recall there was a transmission, a crankcase and engine blocks. They seemed to be pretty reasonable in price. I have not checked to see if they are still listed.

[Matt Harwood]

Just now, Tph479 said:

There were Lincoln Model k parts listed on Marketplace last week on the east coast. If I recall there was a transmission, a crankcase and engine blocks. They seemed to be pretty reasonable in price. I have not checked to see if they are still listed.

 

Gone. I know the guy who bought them. I already tried to buy the transmission off of him to no avail.

[Matt Harwood]

If I remove the transmission top cover and fill it with oil, is it safe to put it in gear and let it idle with the cover off so I can see what's moving and what might be making that sound?

[Grimy]

21 minutes ago, Matt Harwood said:

If I remove the transmission top cover and fill it with oil, is it safe to put it in gear and let it idle with the cover off so I can see what's moving and what might be making that sound?

I have no Lincoln experience, but have done that with my 1918 Pierce at slow (200 rpm!) idle (large oval fill/inspection cover on the top of the case) and I can tell you that the heavy 600W gets thrown around much more than I would have thought.  Pierce manual says to fill to the bottom of the shaft.  Therefore, I suggest (1) firing a warm engine that will idle as low as possible AND constructing a shield of (perhaps) cardboard, and (2) minimal amount of gear oil.

 

A friend had a 1933 Pierce with a strange skip in 2nd gear and found a small piece of debris lodged at the bottom between two teeth.  Easy removal solved the problem.

[pmhowe]

44 minutes ago, Grimy said:

A friend had a 1933 Pierce with a strange skip in 2nd gear and found a small piece of debris lodged at the bottom between two teeth.  Easy removal solved the problem.

Wow! Even Pierces need to floss!

[Grimy]

36 minutes ago, pmhowe said:

Wow! Even Pierces need to floss!

My dentist says that I only have to floss the teeth that I want to keep!

[Matt Harwood]

If anyone's following this thread, the story continues back in the original Lincoln thread here: