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TR2/3/3A tr3 transmission oil fill plug

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barneys56tr3

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I am assuming the plug to check or fill the transmission is on the drivers side halfway between the bell housing and the speedo cable. Just want to make sure before I take it to a machine shop for removal. The gear box tunnel is off so I can get a good look at it and if it is a plug it is beyond help. No dip stick on top and tranny is stamped 26 F-59/. Please advise. Thanks.
 
Aloha Barney,

That is the plug, a square headed soft iron plug. Over time the corners get rounded off with adjustable wrenches and pliers. You might try to get it out with vise gripes before you resort to the machine shop. At one time, the earlier TR gearboxes did have a dip stick.

You can get a replacement plug in either brass or iron from most hardware / home improvement stores. I can't recall the size, but it is common.

The usual LBC supply houses are now selling a wrench with two square "holes", one for the drain/filler plugs and the other fits the rear brake shoe adjuster. I don't recall the price ($10-$15), but it work very well and doesn't deform the plug.
 
Thanks for confirming that.I took off the tranny cover today. The seats and the old carpet are out.Getting ready for the new carpet kit.I tried vice grips. Not a chance. And when I tapped on it with a chisel I got worried because the metal was so soft.Last year I had to drain it and then fill it through one of the large bolt holes on top of tranny with the right amount of oil to make sure it wasn't low.
 
ISTR 3/8" pipe threads.

Probably spray the exposed threads with PB Blaster, let sit for 30 minutes, then apply heat around the hole, then vicegrips will remove the plug.

Use anti-sieze on the threads of the new plug.
 
Last year I sprayed PB blaster and tried the vice grips to no avail.Today I used pb blaster and the propane torch.Nada.That's when I thought it might not be a plug.
 
Iron plug in an Aluminum case spells trouble, equaling elecrtolosis. Hence siezed in tightly. Besides the fact that most people dealing with these oil fill plugs tighten them much too tight! Likely as not heat is going to be your only hope of removing it. A propane torch with the trubo tip MAY supply enough heat. If not you might have to resort to an Oxy/Acetylene torch.
Heat the surrounding Aluminum area around the plug as hot as you dare, Having said that be careful, as Aluminum doesnt display its melting point until it is too late.
once you have heated the area up, wait a thrity seconds or so {Not too long as to let the heat disipate} for the heat to soak in then try turning the plug. Hopefuly it will come out without destroying the threads. when you replace that plug, replace it with a brass one. Use anti sieze compound on it. It only need to be tight enough that it wont vibrate out as you are driving.
Good luck
 
Thanks for the response.I will attack it again tomorrow.I'll soak with pb blaster tonight.And yes, I'm a little worried that I might damage the aluminum casing.I'll just be extra cautios with the heat.Maybe this is a good time to buy a mapp gas kit?
 
Mine is an early TR3A (TS 27489 LO) from Feb. 1958 and it has the dip-stick/filler on the RHS. Later TR3As have a threaded plug on the LHS. I cut a hole in the tunnel of the TR3A that I finished last June for easier access to fill the gearbox. See photo of mine and also the plugged hole in the green tunnel for the late TR3A.

A friend who has a late gearbox with overdrive just bored a hole in the top of his gearbox (the boss cast in the aluminium is there, even if it's not use) and he made a duplicate dipstick, so his late gearbox now has the option of filling via the side plug or the top dip-stick.
 

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Make sure that you heat around the outside of the plug hole avoiding heating the plug itself. The will expand the hole and not the plug. Propane may not get hot enough so try a MAPP gas cylinder on your propane torch. Aluminum melts around 1400F and goes from a solid instantly so be careful not to overheat.

Your machine shop will probably use a oxy torch but you can try again yourself and save the $$.
 
Dont know what you lot call them but I use things like "stilsons" over here . A type of adjustable which the jaws tighten as they are turned . Plumbers over here use them . Get them on good and tight then tap them into movement with a hammer blow . I removed the plugs from various boxes which hadnt been moved in years . No damage either.
 
We call them that occasionaly, but most of the time we just call it a pipe wrench. Which, in this case is the most appropriate tool to use, being that it is a pipe plug that is in there. I've used pipe wrenches on these plugs all the time when nothing else would work. They have always gotten the plug loose. If the plug gets too messed up to re-use, just go buy another one for 49 cents.
 
Yikes, Barney. Think about it, how hard it is to replace that cast aluminum cover? I like the idea of a sympathetic (read that, knows what they are doing) machine shop that can drill and re-tap the hole (should have enough aluminum "meat" left for a slightly larger tapped hole) and put in a fresh, oversized plug. I had to have the refill hole in the side of my TR6 tranny tapped for an oversized plug. The DPO managed to strip it. I went with a hex-headed plug that can be gripped efficiently with a socket.
 
Tkanks B.C.F. members. With your knowledge I must report I have successfully removed the mangled plug. With a combination of pb blaster, propane heat and the stilsons or when I use them they are called a monkey wrench. The plug was in so deep no threads were showing and the head was about the size of a pencil. Now it's time to get out the anti-seize and a new brass plug. Thanks for the good advice.
 
I've never had a problem with the iron plug, but whether brass or Fe the key is to not over-tighten. I usually wrap the threads with a bit of teflon tape... probably overkill but cheap insurance considering how seldom one has to undo that plug.
 
Geo Hahn said:
I've never had a problem with the iron plug, but whether brass or Fe the key is to not over-tighten. I usually wrap the threads with a bit of teflon tape... probably overkill but cheap insurance considering how seldom one has to undo that plug.
Click to expand...

Same here.
 
Geo's advise is very good. Over tightening is the cause of most problems with these plugs. As PeterK pointed out, the plug is 3/8" pipe thread. Pipe threads are generally slightly conical rather than cylindrical (like a bolt or power screw). As a result a threaded pipe joint is much like a conical plug plugging a conical hole. In addition, the threads act as a labyrinth seal. While no gasket is needed, a coating is usually applied to the threads such as Teflon tape, mostly as a lubricant. Due to the wedging effect of the tapered thread, extreme care must be used to avoid over tightening. Additional, overtightened tends to round the corner of the soft iron or brass heads on the plug.
 
After considerable vasilation I finally decided to put in a brass plug and anti-seize, after topping off the tranny with oil. After seeing Don's picture of his tranny I just spent two hours degreasing mine. Looking good.
 
I have a rule regarding car maintenance -- the length of time it will take to complete a task is inversely proportional to the number of nuts/bolts that need to be removed!

It seems the one, two and three bolt jobs always seem to take the longest!!!
 
Sam, Ain't it the truth. I see you are in Olympia. Do you plan to attend the british car show in Belleview this coming July? I hope to be there with my 56 tr3.
 
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