Transmission drain/fill plug washers?

E30 Racer · 01-31-2021, 02:23 PM

In preparation for spring maintenance, I've ordered a bunch of misc parts and fluids. When replacing the transmission fluid, I plan to replace the drain/fill plugs.

Interestingly, the transmission used in the 1M (and N55 powered cars) uses different drain/fill plugs than those of the earlier N54 cars. All plugs appear to be M18x1.5, but the early ones have an integrated sealing ring (viton?) like the diff plugs, whereas the later ones do not. What's odd (to me anyway) is that Realoem does not specify use of a copper/aluminum sealing washer for the later versions.

Is it really correct to install the plugs without any additional means for sealing? Seems like a bad idea, has anyone tried adding a thin crush washer?Thoughts?

CarJunkie · 01-31-2021, 11:41 PM

That's odd. I don't know what is up with realoem, but FCP Euro had the crush washers for the drain and fill plugs for both tranny and diff, which I used. My plugs did not have any incorporated sealing ring. I wouldn't put the plugs in without crush washers...they would leak.

E30 Racer · 02-02-2021, 05:22 PM

Quote:

Originally Posted by CarJunkie

That's odd. I don't know what is up with realoem, but FCP Euro had the crush washers for the drain and fill plugs for both tranny and diff, which I used. My plugs did not have any incorporated sealing ring. I wouldn't put the plugs in without crush washers...they would leak.

Unless it's the really old E30 style diff plug (M10 internal hex), they should have an integrated green oring, and not require a crush washer.

For the transmission, I'm with you. Not cool to think deformation of the case will provide a leak-proof seal 😳.

CarJunkie · 02-02-2021, 06:57 PM

Quote:

Originally Posted by E30 Racer

Quote:

Originally Posted by CarJunkie

That's odd. I don't know what is up with realoem, but FCP Euro had the crush washers for the drain and fill plugs for both tranny and diff, which I used. My plugs did not have any incorporated sealing ring. I wouldn't put the plugs in without crush washers...they would leak.

Unless it's the really old E30 style diff plug (M10 internal hex), they should have an integrated green oring, and not require a crush washer.

For the transmission, I'm with you. Not cool to think deformation of the case will provide a leak-proof seal 😳.

Oh.... now that you mention it, the 1M diff may have had that. I also changed fluids on the RX8 last summer and may have been confusing the two.

PRTSB1M · 02-02-2021, 11:40 PM

The drain/fill plugs on the transmission don't use a crush washer. I recently changed the fluid in my transmission and it feels like there is interference designed into the threads that creates a seal.

01-31-2021, 02:23 PM	#1
E30 Racer Captain 220 Rep 695 Posts Drives: '11 1M, '09 335i M Sport Join Date: Aug 2011 Location: Ohio iTrader: (2)	Transmission drain/fill plug washers? In preparation for spring maintenance, I've ordered a bunch of misc parts and fluids. When replacing the transmission fluid, I plan to replace the drain/fill plugs. Interestingly, the transmission used in the 1M (and N55 powered cars) uses different drain/fill plugs than those of the earlier N54 cars. All plugs appear to be M18x1.5, but the early ones have an integrated sealing ring (viton?) like the diff plugs, whereas the later ones do not. What's odd (to me anyway) is that Realoem does not specify use of a copper/aluminum sealing washer for the later versions. Is it really correct to install the plugs without any additional means for sealing? Seems like a bad idea, has anyone tried adding a thin crush washer?Thoughts?
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01-31-2021, 11:41 PM	#2
CarJunkie Colonel 2617 Rep 2,819 Posts Drives: e82 1M, f87 M2cs Join Date: Nov 2011 Location: Tri-Cities, Washington iTrader: (1) Garage List 2020 M2cs [0.00] 2011 BMW 1M [0.00]	That's odd. I don't know what is up with realoem, but FCP Euro had the crush washers for the drain and fill plugs for both tranny and diff, which I used. My plugs did not have any incorporated sealing ring. I wouldn't put the plugs in without crush washers...they would leak. __________________ 1M track toy mods: BMS chargepipe, BMS OCC, ADE FMIC, ADE motor mounts, MadDad/Lightweight Ti exhaust, ADE custom oil thermostat/cooler, custom MHD tune, F10 550i clutch, Ohlins R+T, Vorschlag camber plates, M3 'vert FSB with Turner endlinks, Stoptech Trophy BBK.
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02-02-2021, 11:40 PM	#5
PRTSB1M Lieutenant 297 Rep 429 Posts Drives: AW3 1M Join Date: Feb 2015 Location: Thunderdome iTrader: (0)	The drain/fill plugs on the transmission don't use a crush washer. I recently changed the fluid in my transmission and it feels like there is interference designed into the threads that creates a seal.
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