AA 4 speed transmission question .

[john charlton]

A fellow club member here in England has an 1930 wrecker/recovery. It drops out of high gear and has asked me for advice . I thought at first the input shaft and 1st/3rd gear were worn allowing it to pop out of gear . This can be caused by careless shifting and poor double declutching. He sent me pics and these parts look in very good unworn condition . He tells me he can move the output shaft ahead and astern about 1/2" . My guess someone forgot to re install the rear AA 7085 rear bearing retainer after a new output shaft was installed This would mean that the juncture between the input and output would be unstable around the Hyatt pocket bearing the misalignment causing the shifter fork being overloaded sideways and popping into neutral . I think the retainer is most likely long gone but I do have a spare AA 7085 B .Would this work I wonder if the small muff coupling cap would fit inside the large forged retainer has anyone done this???

John in Suffolk County England

[Doug in Maryland]

You are right: my experience with one of my AAs is that the teeth on the input shaft and the internal teeth on the 3rd/4th gear were worn on a bit of an angle from having been “thrown” out of 4th gear without the clutch which led to it jumping out of high gear. Replacing these solved the problem. However, if your friend’s gears are in good shape, I would think that as you said, the next most likely culprit is the output shaft’s bearing retainer is not properly installed or is simply missing altogether. I’m not sure about whether the small coupling shaft cup would fit inside the larger retainer. If your friend’s retainer is missing, I’m pretty sure I have extras lying around and would be happy to send one. Might take a few days from the states but happy to look if you’d like.

[Tom Wesenberg]

Also make sure the flywheel cover is dialed in to .006" or less at the 9, 12, and 3 o'clock positions.

[john charlton]

Thank you both for the advice most appreciated . Further investigation reveals the output shaft was renewed because it was damaged at the front end in the pocket area . This original damage caused by the omission of the retainer so the new one was installed with no retainer and the damage caused again !!!

John still in Suffolk County England .

[rotorwrench]

Worn shift fork shafts & detents can have an affect. Too much countershaft end play can also have an effect but that is mostly on the lower gears. It the main shaft has that much play then that's the place to start looking. Once they are in high 1:1 they generally stay meshed but play in either main input or main output are directly related to the mesh of the 1:1 drive.

[john charlton]

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Thank you Doug for your kind offer I will see how we go .

John

[Doug in Maryland]

Originally Posted by john charlton

Thank you Doug for your kind offer I will see how we go .

John

You’re welcome, John. Glad to help any way I can.

[Juggler]

Dear Old Dad will along in a minute....

[john charlton]

I know you all have been waiting with bated breath and yes the retainer AA 7085 B can be used in place of AA 7085 . The muff coupling cap fits neatly in the forged retainer . More totally useless information from the land of the Pilgrim Fathers and Happy Thanksgiving to you all !!!

John still in Suffolk County England .

[Doug in Maryland]

Interesting. Thanks for the follow up!