Removing a welded drain plug

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Beakster
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Removing a welded drain plug

Post by Beakster »

Hi,

I was about to do a gearbox oil change. Took the filler plug out and then went to remove the drain plug and saw it had been welded. When I saw that I decided to stop and ask for some advice as I'm not entirely sure what's happened here and I'll need to be able to get it back in so I can use the van.

Anyone seen this before? My guess is that the hex socket plug rounded so they welded a bolt head onto it? I'm hoping they haven't welded it to the box. If i remove this with a socket and then have a new drain plug on hand think I'll have any issues?

Thanks

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davidoft1
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Re: Removing a welded drain plug

Post by davidoft1 »

Unlikely that the mild steel plug is welds to
The ally gearbox case, more likely they just welded a bolt into it, undoing it is the only way to find out

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MarkHughes
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Re: Removing a welded drain plug

Post by MarkHughes »

I have welded to sump plugs in the past when they are seized and needed heat and/or another bolt welding on for turning them, It looks like this one has been heated in the past to unseize it. It probably isn't welded to the aluminium.

Job 1, Order a new sump nut. Then when you put the new one in, Torque it correctly with a new washer.
1990 VW T3 1900 WBX 5 Speed, 1972 VW T2 Dormobile 1600 Aircooled, 1994 Nissan Skyline R33.

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jrt
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Re: Removing a welded drain plug

Post by jrt »

Does it leak, I can’t tell by properly by the photo?
Obviously some previous owner repair of some sort in the past. You could always use a simple pump to remove the old oil while you see how lucky you feel before removing it.
David.
the future is unwritten

silverbullet
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Re: Removing a welded drain plug

Post by silverbullet »

Ah yes. Welding aluminium to steel. Like gluing chalk to a slice of banana...
1985 Oettinger 3.2 Caravelle RHD syncro twin slider. SA Microbus bumpers, duplex winch system, ARC 7X15 period alloys

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Re: Removing a welded drain plug

Post by silverbullet »

MarkHughes wrote: 06 May 2026, 07:26
Job 1, Order a new sump nut. Then when you put the new one in, Torque it correctly with a new washer.
Its a taper thread plug on the transaxle. No washer.
1985 Oettinger 3.2 Caravelle RHD syncro twin slider. SA Microbus bumpers, duplex winch system, ARC 7X15 period alloys

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MarkHughes
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Re: Removing a welded drain plug

Post by MarkHughes »

silverbullet wrote: 06 May 2026, 12:29
MarkHughes wrote: 06 May 2026, 07:26
Job 1, Order a new sump nut. Then when you put the new one in, Torque it correctly with a new washer.
Its a taper thread plug on the transaxle. No washer.

Ah, So isn't this one supposed to be a 17mm or so hex ? I guess they welded the bolt in due to rounding it or not having the tool.
1990 VW T3 1900 WBX 5 Speed, 1972 VW T2 Dormobile 1600 Aircooled, 1994 Nissan Skyline R33.

silverbullet
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Re: Removing a welded drain plug

Post by silverbullet »

Its a 17mm socket plug, M22 taper thread iirc

https://brickwerks.co.uk/product/gearbo ... wImD67Qm4s
1985 Oettinger 3.2 Caravelle RHD syncro twin slider. SA Microbus bumpers, duplex winch system, ARC 7X15 period alloys

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