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Transmission Drain Plug

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wbdvt

Senior Member
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Hello,

As I am getting familiar with my 80 Spitfire, I followed TR3driver's advice on using Valvoline synthetic 85W90 with GL-5 & MT-1 ratings after a fruitless search for GL-4 ratings. I drained the fluid out, it was very thick, dirty and only seemed to be about a pint in there. There was glob of heavy stuff on the magnetic part of the drain plug. Plans are to drive it for about an hour and then drain and fill again to do a good flush.

This brings me to my question. The drain plug does not seat all the way against the tranny case and weeps. Should it fit flush and is there a thread sealer I can use to stop the leak?

See picture... Photobucket Pic
 
:iagree:
The threads are tapered, and are where it is supposed to seal, so the plug should not fit flush against the case. Better to use the paste form than the more common tape, so it can't break off into strings inside the case.

21Il%2BNO0MKL._SL500_AA300_.jpg


If it still weeps, then likely the threads are damaged (or that plug is the wrong thread). There are stronger sealants available (Eg, Loctite 565 ) but they shouldn't be necessary.

BTW, I advocate swapping the factory plugs for hex socket pipe plugs, which don't stick out as far (so less likely to catch a rock) and are less apt to round off next time IMO.

DSCF0025.jpg
 
wbdvt said:
can you buy the hex head with magnetic piece to catch any metal debris?
Click to expand...
Yup. https://www.mcmaster.com/#magnetic-pipe-fitting-plugs/=9xzqij

The magnet doesn't stick out like on the plug (I think) you have, but it's quite strong and seems very effective.

Scared me silly when I put one in the crankcase of my Stag. Next oil change, I found part of a timing chain roller stuck to the plug! (Stags are famous for timing chain problems that lead to ex$pensive rebuilds.) But after getting the timing cover off, I realized that the failed chain had already been replaced before I got the car! That piece of roller had been roaming around in the pan for who knows how long, without being flushed out by an oil change.
 
Randall - thanks for the info. I will measure up the plug and order away. As a side note, thanks for your input on my question about the GL-4 fluid. I went with the Valvoline synthetic blend 85W90 as I could not find any GL-4 around here in Vermont.
 
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