47 Tranny won't go into 3rd gear

[Mart]

Wow. good find.

Hopefully it should be a straightforward fix.

Mart.

[JSeery]

My first question would be why did it break?

[Marv]

Henry i would replace the synchronizer hub with a newer version without the balls. They work better.

[Terry,OH]

Talk to Mac VanPelt to get his experience. IMO the 81A syncro hub, you have, is strong, but I use the 3 thick, wide, solid metal inserts for the 3 steel balls instead of the stamped steel insert, that has broken for you. The thick metal inserts are a direct replacement to your broken insert. I would not use the style hub for the 3 thin cast metal inserts. These seem to crack and brake. I stay away from the hub and inserts that use the two large diameter spring rings on each end. The inserts are again stamped steel and the spring rings can loose some of their ability to spring back. Since you have it apart check ALL the end plays and replace both of the blocker rings, bearings, thrush washers. Have some fun doing the job.

[rotorwrench]

I've had good luck with the spring ring set up in my Mercury overdrive transmissions. On last overhaul, one of the transmissions had 140K miles and the synchro assembly was still in very good condition. The old ball bearing types used to break the little springs under the balls so they had their ups & downs too. Everything wears out eventually. Old Henry is still in every day service so things will wear out.

[Old Henry]

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Originally Posted by JSeery

My first question would be why did it break?

Mine too. And the second question is, why didn't the little piece just fall out and into the bottom of the tranny out of the way of harm? And, when I took the syncro apart, the little piece was found inside the insert, not jammed where it must have been jammed. Will probably never know.

Here's the ring showing where the little piece jammed it.

[Charlie ny]

Henry,
Ask Mac for the solid keys not the die stamped variety.
Charlie ny