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Gearbox shimming

Submitted by george_phillips on Thu, 21/06/2018
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On dismantling the drive side (trying to find why it's back to not wanting to go into neutral) I find the following (laydown box mid fifties):

The main gearwheel bush (plate TN17) seems able to slide out of the g/box until it hits - presumably - the inside edge of the clutch spider. Is this normal?

The mainshaft has about 25 - 30 thou movement (float?) - my estimate - very tricky to check precisely. It's about 2/3 a millimetre (40thou). Is this OK?

If it's not and I need shims, what size do I get and where do they go? I would assume on the mainshaft at the timing end before it goes into the g/box inner cover?

Sorry for all the queries but as I have it all apart I may as well try and get it right - again!

Thanks for any help.

George

Submitted by george_phillips on Thu, 21/06/2018

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I think TN16 is the oil retaining washer on the drive side of the main gear wheel. As I fitted a new bearing with 2 seals (the inner of which I removed) I dispensed with the washer as it was no longer needed.

George

Submitted by george_phillips on Thu, 21/06/2018

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Could be, Barry. But if I fit it the bearing may be starved of oil as it will sealed at both ends?

George

Submitted by george_phillips on Fri, 22/06/2018

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Having slept on it I think you have a point, Barry. I'll pull the innards of the box out and refit that washer to see what difference it makes. I'll also check it's width first.

George

Submitted by george_phillips on Fri, 22/06/2018

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G/box disembowelled. That washer is missing as I thought. I've ordered 2 (just in case) from RGM.

As a side issue, the general consensus seems to be that fitting a mainshaft bearing with built-in oil seals is the way forward. No mention was ever made of fitting shim washers to take the place of the two seals omitted. I should have realised that you can't omit somethng on a shaft and expect everything still to line up.

George

Submitted by george_phillips on Sat, 23/06/2018

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Thanks Michael. Now ordered. Gives me a bit more to play with. Just wish the weather wasn't so good!

George

Submitted by george_phillips on Sun, 24/06/2018

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On re-watching Mick Hemmings' Gear Box DvD I see that he notes a circlip to hold the main gearwheel bush (TN17) in place. There is not mention of it in the '55 parts book. Is it a later addition (or AMC box bit)?

George

 


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