Overdrive Drain Plug Washer

[Burkee]

Changed my gearbox oil today and realized when I drained the old oil that the brass drain plug washer for the overdrive was at the bottom. I hadn’t reinstalled it. Will I lose all the fresh gearbox oil when I take the brass drain plug off again? Filter was clogged and there was a lot of sludge.

 

[John Turney]

You will lose a lot of it, but not all. You could make sure the case area is clean and drain it into a very clean container. Or, chalk it up to a lesson learned.

 

[Michael Oritt]

Burkee--

It's good practice to anneal copper/brass washers by getting them red hot with a map gas torch or the like--it softens them and provides a better seal.

 

[Burkee]

Thanks, I’ll do that. Red hot with torch.

 

[Michael Oritt]

Thanks, I’ll do that. Red hot with torch.

Yes, and I also like to safety-wire all oil plugs.
"Just for Pretty" as the Quaker saying goes.

 

[Burkee]

Burkee--

It's good practice to anneal copper/brass washers by getting them red hot with a map gas torch or the like--it softens them and provides a better seal.

Is the wash copper or fiber?

 

[Michael Oritt]

Is the wash copper or fiber?

Burkee--

Fiber washers are usually discarded after one use whereas copper crush washers can be reused, and annealing softens them to provide a good seal and prevent loosening.

The washer pictured in your first post looks like copper but you'll definitely determine whether or not it is fiber when you hit it with the torch!


.

 

[Bob_Spidell]

Burkee--

It's good practice to anneal copper/brass washers by getting them red hot with a map gas torch or the like--it softens them and provides a better seal.

Whoa, Nellie! I've never seen anything BUT fiber washers on the O/D drain plug. That is almost certainly a fiber washer in the photo, it won't take kindly to annealing. Maybe you're thinking of the engine pan plug? Also, though I'm a big fan of safety wiring, there's no provision for it on the O/D plug and, though you could drill a hole in one of the plug 'ears' I don't know where you could anchor it.

As an aside, I have noticed--I think--that the available fiber washes are narrower, periphery-wise, that what has been available in the past and I haven't been able to seal up a plug adequately with them. If anybody knows where to get either quality fiber washers or copper washers of that size I'd like to hear about it. I like to soak fiber washers in a light oil for a day or so before installing.

To the OP, if you got a lot of 'sludge' out of your O/D drain I'd think seriously of some sort of flush (note the O/D and the gearbox share the same oil). I'd be tempted, though I've never done it, to run some sort of mild solvent--kerosene/paraffin/diesel maybe--through for just a couple minutes at idle then drain and refill with fresh oil at least twice (cycle the O/D). The 'safe' bet would be to run detergent engine oil--yeah, yeah, I know the original, 70 year-old manual says to use non-detergent (later manuals say otherwise)--for a hundred miles or so then drain. Rinse and repeat.

(Edit) ps. You'll want to drain the gearbox as well; near as I can tell, about a cup or so remains in it when you drain from the O/D.

 

[Michael Oritt]

I haven't had an OD since 2002 when I replaced the 3-speed with a Toyota box and wrongly assumed the washer was metal.
Nevermind....

 

[Burkee]

Whoa, Nellie! I've never seen anything BUT fiber washers on the O/D drain plug. That is almost certainly a fiber washer in the photo, it won't take kindly to annealing. Maybe you're thinking of the engine pan plug? Also, though I'm a big fan of safety wiring, there's no provision for it on the O/D plug and, though you could drill a hole in one of the plug 'ears' I don't know where you could anchor it.

As an aside, I have noticed--I think--that the available fiber washes are narrower, periphery-wise, that what has been available in the past and I haven't been able to seal up a plug adequately with them. If anybody knows where to get either quality fiber washers or copper washers of that size I'd like to hear about it. I like to soak fiber washers in a light oil for a day or so before installing.

To the OP, if you got a lot of 'sludge' out of your O/D drain I'd think seriously of some sort of flush (note the O/D and the gearbox share the same oil). I'd be tempted, though I've never done it, to run some sort of mild solvent--kerosene/paraffin/diesel maybe--through for just a couple minutes at idle then drain and refill with fresh oil at least twice (cycle the O/D). The 'safe' bet would be to run detergent engine oil--yeah, yeah, I know the original, 70 year-old manual says to use non-detergent (later manuals say otherwise)--for a hundred miles or so then drain. Rinse and repeat.

(Edit) ps. You'll want to drain the gearbox as well; near as I can tell, about a cup or so remains in it when you drain from the O/D.

The sludge was mostly in the screen, magnet washers and the inside of the brass plug. Soaked them in gas and used a tooth brush to go over them. Seemed to be some sediment in the used motor oil pan when I poured the used gearbox oil into the container. I was thinking of using the new oil, once I drain the gearbox, over again. It sounds like it’s better to use that as a flush. I had a hard time finding 40 sae conventional non-detergent oil. Ending up going with Pure Guard. It’s definitely a fiber washer so it looks like I can’t use it again. If I used permatex could I use it again? Appreciate the advice. Ed

 

[Bob_Spidell]

I've tried all manner of goops to get a seal on the O/D plug; best results have come from Permatex Seal&Lock, but I'm still leaking. I may have a non-flat surface or, gawd forbid, a crack in the flange, and I'm not happy with the newer fiber gaskets. I just remembered Michael O. has a source for copper crush washers; I'll have to look it up.

I've never bought the 'use non-detergent oil so all the crud sinks to the bottom' theory. I've run either Castrol 20W-50 or, mostly for 100K miles or so Redline MT-90. Bottom of gearbox and O/D have always been clean; when I do change it out there is a very fine, and pretty, brass shake suspended in the oil. It's so fine you can't feel it on your fingers. Note some quality greases; e.g. 'moly' and lithium, use finely ground soft metal for a thickener

 

[Michael Oritt]

All the crush washers you could hope for: Dorman Oil Drain Plug Gasket Assortment-p/n 66222

 

[BobHaskell]

I've tried all manner of goops to get a seal on the O/D plug; best results have come from Permatex Seal&Lock, but I'm still leaking. I may have a non-flat surface or, gawd forbid, a crack in the flange, and I'm not happy with the newer fiber gaskets. I just remembered Michael O. has a source for copper crush washers; I'll have to look it up.

I've never bought the 'use non-detergent oil so all the crud sinks to the bottom' theory. I've run either Castrol 20W-50 or, mostly for 100K miles or so Redline MT-90. Bottom of gearbox and O/D have always been clean; when I do change it out there is a very fine, and pretty, brass shake suspended in the oil. It's so fine you can't feel it on your fingers. Note some quality greases; e.g. 'moly' and lithium, use finely ground soft metal for a thickener

I understood that the reason not to use detergent oil was the overdrive would cause detergent oil to foam.

 

[Bob_Spidell]

I understood that the reason not to use detergent oil was the overdrive would cause detergent oil to foam.

I'd never heard that. It actually makes mores sense; foaming could reduce hydraulic pressure and lubrication in the O/D. My 100's OM spec's non-detergent, but Bentley's 100-6/3000 manual doesn't; possibly because anti-foaming agents got added to oils later. From Generative AI: 'Yes, detergent oils can foam, though modern formulations often include defoamants to mitigate this.'

Thanks, Bob.

 

[kozelding]

Actually, despite what the internet seems to maintain, I believe it's the other way around: old fashioned oils with limited additive packages are prone to foaming if churned, and modern oils have very good anti-foaming additives.

The presence of detergent doesn't change the foaming properties — it's not dish soap

 

[Burkee]

So it would be ok to use 20w50 zr1 racing oil? Or just 20w50?

 

[kozelding]

If you search, you'll find people have strong opinions on gearbox/OD oil choices — non-detergent 30, normal 20w-50, 15w-80 gear oil — all backed by some logic and/or experience.

One theory, for example, is detergent oil is bad because it's more likely to keep debris in suspension and circulating, rather than letting it settle.

My own take from all that is it actually doesn't matter. ODs aren't that fragile.

(Personally, I use 20w-50 VR1 — I drive in cold weather, so I like the multi-weight, and I like the idea of anti-foaming agents.)

 

[WHT]

Gearbox oils don't need detergents.

More importantly, detergents will strip high pressure wear additives from metal surfaces; and they ARE needed.

 

[John Turney]

I'd never heard that. It actually makes mores sense; foaming could reduce hydraulic pressure and lubrication in the O/D. My 100's OM spec's non-detergent, but Bentley's 100-6/3000 manual doesn't; possibly because anti-foaming agents got added to oils later. From Generative AI: 'Yes, detergent oils can foam, though modern formulations often include defoamants to mitigate this.'

Thanks, Bob.

When the 100 was released, non-detergent engine oils were typical. When the 100-6 was released, engine oils typically had detergents. They were ok for transmissions. Ideally, you want a GL-4 gear oil in the transmission. Engine oils are approximately equivalent to a GL-3. GL-5 gear oils can attack brass parts.

The SAE viscosity grades for engine oils are different than the grades for gear oils. A SAE 50 engine oil is approximately the same viscosity as a SAE 90 gear oil.

Synthetic oils tend to leak more than conventional oils. If you don't have a leakage problem, a synthetic 80W-90 GL-4 gear oil is easy to find. A conventional 80W-90 GL-4 gear oil is harder to find. Driven makes one.