HeywoodFloyd

HeywoodFloyd

Active Member
I have always had drops of oil forming on the gearbox since I've had my landy (3 years).
Recently I noticed a bit of extra transmission whine, so I figured I'd change the oil in the gearbox and see what I get.
I've now discovered why I get a slow leak from the gearbox. My extension case drain plug is cross threaded, and whoever did my last oil change for me when I had it serviced, just didn't bother telling me.

Basically the plug will do up a fair distance while cross threaded, but it finally jams up a few millimetres before pinching the washer.

They left it like this, and slowly the oil has been draining out. There was nowhere near enough in there when I opened it all up, the level was quite low. It's taken a year to get this bad though.

So, what are my options now? Obviously I can just put it back on as is and fill up and let it all slowly drain out again over the next year or so, or really, I'd like to sort the problem out correctly.

Any ideas?
 
Last edited:
The way I see it you have 3 options.

1. Drill and tap for a bigger size.
2. Helicoil
3. Two washers.

J
 
Depending on how bad the existing hole is, you could retap with the standard size. There shouldn't be a huge strain on these plugs, they are just filling the 'ole.
 
HeywoodFloyd said:
I have always had drops of oil forming on the gearbox since I've had my landy (3 years).
Recently I noticed a bit of extra transmission whine, so I figured I'd change the oil in the gearbox and see what I get.
I've now discovered why I get a slow leak from the gearbox. My extension case drain plug is cross threaded, and whoever did my last oil change for me when I had it serviced, just didn't bother telling me.

Basically the plug will do up a fair distance while cross threaded, but it finally jams up a few millimetres before pinching the washer.

They left it like this, and slowly the oil has been draining out. There was nowhere near enough in there when I opened it all up, the level was quite low. It's taken a year to get this bad though.

So, what are my options now? Obviously I can just put it back on as is and fill up and let it all slowly drain out again over the next year or so, or really, I'd like to sort the problem out correctly.

Any ideas?
Click to expand...

Leave the hole as it is. Use PTFE tape on the plug threads and stop the oil from passing along the thread.
 
HF, I've had similar issue albeit with a MKII Jaguar on a Moss 'box. PTFE'd and copper washered first, it held for a good while but still leaked. Then tapped but the thread was never happy where it had been previously butchered. Finally helicoiled and the result was perfect. I part drained 'box, ran a good amount of grease around inside of plug hole to catch swarf. Post drilling/before fitting helicoil carefully removed grease with a piece of wire coat hangar then drained remaining oil. Then flushed gearbox and fitted helicoil. Filled with correct oil level and test drove. Re-drained oil into a fine filter to inspect for fine particle swarf, it's was perfectly clean; job done.
 
That’s a bit defeatist ;)
Can you drill a straight hole?
Can you turn a tap?

Single size helicoil kits come with all you need.

Or next size up you only need a correct drill, tap & new plug.

You can do it man have faith the guys will talk you through :D:D

J
 
The issue with this will be that the plug holds s small filter, I can't just go for a generic larger plug. That's what you're suggesting right?

It's got to be the same plug I think.
 
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