Manual Gearbox Drain Plug
 

Evening,


Whilst having some other work done, I had my gearbox oil replaced by a reputable mechanic earlier in the year. Unfortunately soon after I noticed oil on the drive and found it was coming from the drain plug area. I cleaned it up thinking it was spillage. Over time it got worse. it decided to drop the oil myself and take a look at the plug.


My problem: The drain plug will not undo and simply spins, I then tried to torque it back up and, yep it spins again so guessing stripped thread. The dripping has got worse. After some trying, I have managed to get it to 'bite' on the the thread when undoing but it goes really tight as though it's undoing at an angle or going to cross thread! When I screw back clockwise it goes loose and spins. I'm reluctant to force undo in case I make it worse but not sure what else I can do...:shrug:

Any ideas?


https://www.the75andztclub.co.uk/for...e674cbb8a2.jpg

If it is a stripped thread, a replacement sump, or sump off and helicoil the thread. Arguably you could helicoil with the sump fitted, but I'd be too nervous about getting some debris in the gearbox to risk it...

put a flat screwdriver behind the edge of the plug and lever while undoing, hopefully it will bite on a thread and come out.

If not, you will have to drill the plug out then helicoil the gearbox to repair.

Easy. Have a new thread tapped into the hole. There is enough metal to take it. Then use the appropriate size bolt.

Magnetic sump plugs are also available in various sizes.--:D

Are you sure the plug is spinning, only from the photo it looks like the hexagon recess has rounded out?

If that is the case then try carefully chiselling it the edge to undo it.
















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Totally agree, I'd remove the sump also before doing a heli coil but I'd opt for a replacement sump first

macafee2

Grip in the plug head is good (not rounded at the moment). The plug turns freely until it bites on undoing (anticlockwise) then goes really really tight. Obviously threads are damaged. It wont tighten up at all so the transmission fluid is happily escaping for freedom. I'll get to have another look later and will keep trying to encourage it to come out.

Some mention removing the sump? This is the gearbox drain plug not the engine oil plug so not sure if I'm missing something, however someone did mention removing the gearbox :eek:.

I've just realised, I got confused its not the sump is it:duh::duh:
Ignore references to sump, sorry
I still would not want to helicoil without being able to clean the swarf away from the inside.

macafee2

Good point :duh:

When tapping a new thread into the hole use thick grease on the tap. Remove and clean it several times.
It will work and the idea is used in the trade for these kind of emergencies and in mechanical engineering too.

If you're paranoid about it then poke a piece of lint free cloth into the hole and hook it out after you have finished.

PS. You can also hold a vacuum cleaner pipe near the hole and keep sucking air and any particles of metal out as you are doing the tapping.

You guys, stop trying to make work for yourselves.---Lol.