Gearbox Input Shaft / Coupler Wanted

[dmc4087]

Hi all

I am on the lookout for a primary shaft. Hoping somebody that has fitted a one piece shaft and has one of these lying in the back of the shed

Many thanks

[dmc4087]

Here is a video of the play in the shaft


https://www.youtube.com/watch?v=GQEDw1GUqc4

[Nicholas R]

What gearbox is that? Curious why it's got a speedo gear on it.

Have you disassembled the gearbox yet and inspected the shaft? I'd almost bet money that your problem is not the main shaft but actually the inside of the coupler.

Both the clutch and main shaft are case hardened, whereas the coupler is not. The coupler is ~20HRC (not heat treated or hardened) compared the shafts which are 45-55HRC (depending on where you measure). It's a fairly basic principle that when two parts rub, the harder part machines the softer part. The most likely situation is that the splines inside your coupler are worn away by the splines of the main shaft, and the rocking you're seeing is pivoting about the spring pin in the coupler and main shaft.

[dmc4087]

I think it was used in a Renault 25 at one point in its life

The gearbox has not been disassembled. That makes sense what you are saying

Ed agrees with you too - sent me this link https://www.simon-auto-shop.de/epages/Simon-Auto-Anlasser-Lichtmaschinen.sf/en_GB/?ObjectPath=/Shops/Simon-Auto-Anlasser-Lichtmaschinen/Products/091313

I think that might be the way to go, thanks for the input


What gearbox is that? Curious why it's got a speedo gear on it.

Have you disassembled the gearbox yet and inspected the shaft? I'd almost bet money that your problem is not the main shaft but actually the inside of the coupler.

Both the clutch and main shaft are case hardened, whereas the coupler is not. The coupler is ~20HRC (not heat treated or hardened) compared the shafts which are 45-55HRC (depending on where you measure). It's a fairly basic principle that when two parts rub, the harder part machines the softer part. The most likely situation is that the splines inside your coupler are worn away by the splines of the main shaft, and the rocking you're seeing is pivoting about the spring pin in the coupler and main shaft.

[dmc4087]

What gearbox is that? Curious why it's got a speedo gear on it.

Have you disassembled the gearbox yet and inspected the shaft? I'd almost bet money that your problem is not the main shaft but actually the inside of the coupler.

Both the clutch and main shaft are case hardened, whereas the coupler is not. The coupler is ~20HRC (not heat treated or hardened) compared the shafts which are 45-55HRC (depending on where you measure). It's a fairly basic principle that when two parts rub, the harder part machines the softer part. The most likely situation is that the splines inside your coupler are worn away by the splines of the main shaft, and the rocking you're seeing is pivoting about the spring pin in the coupler and main shaft.

Managed to get the case split - Your youtube videos were very helpful, thankyou

I found that the roll pin appears to have fractured (maybe due to movement in the coupler?) and its remains created the wound in the clutch tube.

Looks like my primary shaft splines are ok, so will replace that coupler - maybe the roll pin can be reused? :p

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