Gearbox overhaul

Technical questions and Maintenance advice post in here please
Hurtzberg
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Re: Gearbox overhaul

Post by Hurtzberg »

Oh dear, I started taking it apart.
Andrew

1957 A35
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Re: Gearbox overhaul

Post by Big Daddy »

Hurtzberg wrote:Oh dear, I started taking it apart.
Have the detent plungers flown across the workshop yet :?:
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gazza82
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Re: Gearbox overhaul

Post by gazza82 »

You warned me about those which is why mine is still wrapped and untouched!!
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Hurtzberg
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Re: Gearbox overhaul

Post by Hurtzberg »

Probably should have turned the music off so I had some chance of hearing if that happened.
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Re: Gearbox overhaul

Post by Big Daddy »

You wont hear plunger or spring fly through the air, never to be found again... :mrgreen:
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Hurtzberg
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Re: Gearbox overhaul

Post by Hurtzberg »

It all looks very clean in there. The laygear had no play at all - couldn't get even a .0025 feeler gauge in. Layshaft looked very good too. Wouldn't be surprised if this was rebuilt fairly recently.

Having said that, there was a fair bit of movement from the 1st and 3rd shafts but I don't know what is considered excessive. Is that cured with just new bearings or do these get shimmed too ?
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Neil Evans
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Re: Gearbox overhaul

Post by Neil Evans »

You're probably worrying about nothing as the first and third motion shafts are supported at both ends once the gearbox is part of the drive train...
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Big Daddy
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Re: Gearbox overhaul

Post by Big Daddy »

By bushes... :thumbs:
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Hurtzberg
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Re: Gearbox overhaul

Post by Hurtzberg »

A fresh pair of eyes saw this pitting on the laygear

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Dave Clark
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Re: Gearbox overhaul

Post by Dave Clark »

That is first gear of course and as long as you are fairly gentle with take offs it will last a long while, if a bit noisy - but aren,t they all ?
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Countryboy
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Re: Gearbox overhaul

Post by Countryboy »

Dave Clark wrote:That is first gear of course and as long as you are fairly gentle with take offs it will last a long while, if a bit noisy - but aren,t they all ?
"Fairly gentle" :rol:

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Re: Gearbox overhaul

Post by Big Daddy »

Hurtzberg wrote:A fresh pair of eyes saw this pitting on the laygear
That tooth damage is much worse than just pitting - I'd be inclined to have a spare gearbox ready to fit before the inevitable happens... :whistle:

Alternatively don't select first or reverse gears... :rol:
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beko
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Re: Gearbox overhaul

Post by beko »

It looks like it might have some foreign body jammed between the teeth perhaps? The edges of the teeth look surprisingly good, so it's shame it has that damage.
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Re: Gearbox overhaul

Post by Big Daddy »

beko wrote:It looks like it might have some foreign body jammed between the teeth perhaps?
Don't think so... :whistle:

Looking at the second gear tooth from RHS of photo, there is damage starting on the contact face. This is caused by wear breaking through the tooth's hardened external surface. After this outer surface becomes damaged, the tooth will wear very rapidly.

That's happened already to the first tooth from RHS. It's simply further along the wear path. At that advanced state of damage, I would expect shear failure imminently.

Usually trapping any hard debris results in immediate catastrophic tooth failure not localised damage :!:
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