Crush Washer Sizes

[Eric1855]

I tried searching but no luck.

Does anyone know what size crush washers are used on the differential fill and drain plugs?

I saw the oil plug is M16, are these the same?

I really don't see the need to drive into town and pay a dealer when you can get them from the local auto parts store for $1. I'd just like to know which sizes to pick up ahead of time, instead of pulling it off and taking it up.

Thanks!

[No Limit Motorsport]

Originally Posted by Eric1855

I tried searching but no luck.

Does anyone know what size crush washers are used on the differential fill and drain plugs?

I saw the oil plug is M16, are these the same?

I really don't see the need to drive into town and pay a dealer when you can get them from the local auto parts store for $1. I'd just like to know which sizes to pick up ahead of time, instead of pulling it off and taking it up.

Thanks!

You don't need to change them. They are flat aluminum washers.

[diirk]

Originally Posted by No Limit Motorsport

You don't need to change them. They are flat aluminum washers.

I just bought some from the local dealership for the diff. They were crush washers.

[No Limit Motorsport]

Originally Posted by diirk

I just bought some from the local dealership for the diff. They were crush washers.

Than its the transmission only that has the flat aluminum? Either way there is no issue reusing them, they seal just fine.

[Sportsguy83]

Originally Posted by No Limit Motorsport

Than its the transmission only that has the flat aluminum? Either way there is no issue reusing them, they seal just fine.

From another post:

Originally Posted by xn7485

Just got a both pairs with part numbers quoted from Opie at Subaru. Rear diff drain and fill plugs look identical, but are both crush type washers. I recommend getting new ones to form a better seal. Price is 1.73 for fill, 1.98 for drain.

Yes, the transmission fill/drain washers are freaking $7.87 each. These are solid washers, and do not seem like they require replacing, but I special ordered these so I bought them. Though I got them at net price it was still freaking $5.19/washer.

You are correct.

[diirk]

Originally Posted by No Limit Motorsport

Than its the transmission only that has the flat aluminum? Either way there is no issue reusing them, they seal just fine.

That makes sense. Any chance you can get the size and we can look for a reasonably priced replacement option?

[No Limit Motorsport]

Originally Posted by diirk

That makes sense. Any chance you can get the size and we can look for a reasonably priced replacement option?

I will see what I can do.

[Dave-ROR]

Originally Posted by No Limit Motorsport

Than its the transmission only that has the flat aluminum? Either way there is no issue reusing them, they seal just fine.

Even those should be crush washers. When you use one of the new ones you'll feel it crush. Honda's been using that style for a long time. They look like normal washers, until you use them the first time. I wonder if my old S2K ones would fit...

[No Limit Motorsport]

Originally Posted by Dave-ROR

Even those should be crush washers. When you use one of the new ones you'll feel it crush. Honda's been using that style for a long time. They look like normal washers, until you use them the first time. I wonder if my old S2K ones would fit...

My point is when you reuse them at least the first time they seal and don't leak what so ever. I am all for changing out something if there is a benefit but if it doesn't leak than its working.

[Dave-ROR]

Originally Posted by No Limit Motorsport

My point is when you reuse them at least the first time they seal and don't leak what so ever. I am all for changing out something if there is a benefit but if it doesn't leak than its working.

Well sure you can reuse them until they leak but any leakage is more expensive with these fluids than the cheap crush washers are. :shrug:

My point was simply that I highly doubt they are normal washers, despite their appearance.

[Sportsguy83]

Originally Posted by Dave-ROR

Well sure you can reuse them until they leak but any leakage is more expensive with these fluids than the cheap crush washers are. :shrug:

My point was simply that I highly doubt they are normal washers, despite their appearance.

thanks for your input, and thanks for changing my mind, I'll replace them now

[No Limit Motorsport]

Originally Posted by Dave-ROR

IF they leak but any leakage is more expensive with these fluids than the cheap crush washers are.

I am messing around, if you guys want to change the washers, have at it. No harm done.

[Dave-ROR]

Originally Posted by No Limit Motorsport

I am messing around, if you guys want to change the washers, have at it. No harm done.

Agreed and I've reused them before on other cars. It also depends on how often you reuse them. If you are someone who changes trans and diff fluid often (which I do with any car I track) then you'll see them fail a lot sooner than a car that gets a trans fluid change every 100,000 miles

For this first change I re-used them even since I haven't gotten my replacements in yet.

[developer]

So I just received my overpriced gaskets/washer for the transmission and the differential:

Differential fill plug gasket: SU00300122 - 24mm OD x 18mm ID x 2mm Crush
Differential drain plug gasket: TOY1215710010 - 24mm OD x 18mm IDx 2mm Crush
Transmission fill/drain plug gasket: SU00303626 - 24mm OD x 18mm ID x 2mm Flat

They all look to be aluminum but that is just a guess. All measurements were made with calipers.
Edit: The crush washers stuck to the magnet on the drain plug so I guess they are not aluminum

Left Image is the diff drain/fill gaskets and they look identical. They are the exact same outer/inner diameter and thickness. They are both crush type washer.

The right image is the transmission fill/drain plug gasket is the same size as the differential gasket but is a flat washer.

After I pull the transmission gasket I will compare the thickness of the used and the new gasket to see if the transmission flat washer did actually "crush".
Edit: The original flat washer was within a 1000th of an inch of the new flat washer so I would guess they are not meant to crush.

When I order the differential crush washers again I will just order two of the same part number instead of two different parts.