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TR4/4A Selector shaft seals

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C

clanofwolves

Freshman Member
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My ‘62 TR4 has always had issues leaking oil at the selector shaft seals, and replacing the O-rings didn’t do squat as the plate seems to be a pathetic mate for the O-rings. Have I been missing something? The exploded parts diagrams show what I have, but this cannot be what was expected (gear oil running down and getting on the exhaust. Assistance and thanks in advance are freely given.
 
It appears that the original rings were not round, but either oval or rectangular in cross section. The cavity is too deep for modern round O-rings to fit snugly.

Herman van den Akker once told me that he machined brass washers to fill that gap. What I use are " PTFE backup rings" from MMC. (Plus the O-rings of course.)
https://www.mcmaster.com/9560k53
 
On mine the center rail had rough spots, presumably from the staking process when the end was attached at the factory, which were exactly where the o-ring rides. I smoothed them out on the lathe but a file would work too. I'd be interested in knowing if others had this issue. My TR3 transmission did not.
I also used backup rings, as Randall suggests but I'm quite sure the real culprit was the shaft. (Quite sure I have some left over and can mail the to you. PM if that would help.)
Tom
 
The only thing that I have found that works are quad rings, the size you need is QR-112 ID1/2" OD11/16" they will stop the oil leaking.

Graham
 
While you're working on it, double check that the air vent on the tail housing is open. If the vent gets clogged the tranny will leak no matter how good your seals are.
 
MMC has them
https://www.mcmaster.com/90025k226

Vent hole is in different places on different gearboxes; likely it's possible to assemble a mix that doesn't have one.
eGKkGAk.jpg
 
You can try asking MMC; used to be they would break a bag/box for a "modest" charge, but the charge usually wound up being as much as buying the box.

5I9J785.jpg
 
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