Gearbox Square End Filler Plug

[4129R]

At the end of a big total rebuild, I am putting the fluids in.

The gearbox fill plug has seized solid. I cannot move the square end with a 10mm spanner, even with heat. The spanner/wrench just slips off

I went to two car tool shops and neither had any tool to fit all 4 sides of the plug to get a tight fit.

Brainwave, the square end is 10mm. What about getting the square end of a 3/8" socket on to the plug, link 2 x 13mm sockets together with a long 13mm nut, and then use a long extension bar on the other end of the socket/nut/socket sandwich?

Tomorrow, light filing on the burred square end of the plug to get the socket to fit snugly.

It seems you cannot get a socket to fit a square plug/nut, and double hex sockets do not grip enough of the soft metal plug.   

[BDA]

I filed my drain and fill plugs to 3/8" and used a 3/8" 8 point socket. Then I found out that 10mm 8 point sockets are not hard to find! Having said that, I was unable to find a 10mm 8 point socket quickly at either ebay or amazon. They are out there though!

[bjthomp]

I don't know if this will work for you, but my notes indicate that I've been using a 12pt.-12mm socket to remove and replace the drain & fill plugs. If I recall, the tool fits snugly and doesn't slip. The plugs are original and are stamped 3/8.

[Pfreen]

This will work for you.  https://www.amazon.com/gp/product/B008TOHA6Q/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

[Kendo]

Many many years ago, our VP of operations had a Snap-On account. I got a square 10mm socket from them for that plug. Works great. (And my only Snap-On tool to date  )

[4129R]

Success. I had to move the gearchange out of the way by removing the long 1/4" bolt on the U/J.

The plug, socket, long nut, socket, 1/2" drive extension bar combination worked easily.

After I filed off the burrs, the socket square end tapped on to the drain plug right up to the thread quite easily.