MTFCA Forum

Hello everyone,
I would need the clearenc between the clutch shift (transmission clutch slide collar) and the driving plate shaft of a 26/27 engine. What was the factory measurement?
Can someone help me.
My driving plate shaft was badly worn and I turned it off 0.016 inches. Now i do a new transmission clutch slide collar.

Thank you
Markus

Might machining the output shaft .016" have upset the depth of hardening on the shaft? I would be fitting another shaft rather than machining it down that far. I understand that spares in Germany may be harder to come buy, but they are not that scarce.

Allan from down under.

Hi Allan,
thanks for the answer.
Are you sure that this shaft is surface hardened? I didn't feel anything there. The transmission clutch slide collar is hardened.
It would make sense if the shaft was hardened. But I didn't feel any of it.

Thanks
Markus

It's not uncommon to turn down the output shaft to true it up and remove wear. However, I believe it's usually only done in the area that runs in the fourth main, (requiring an undersized fourth main). If the shaft is heat treated at all, it's most likely through hardened and not surface hardened. I've turned down a few and never noticed any surface hardness.

Honestly, while .016 is a very sloppy fit, the sliding collar is usually either being pushed forward against the clutch fingers, or pushed back against the clutch spring 99% of the time. It's ability to rattle around loose would very limited. I'm not sure if .016 would even be a problem. It's not a heavy part, so running .008 off center probably would not create a balance issue either. I suppose the .008 runout could play havoc with the throwout collar, hovwever. I'd be more concerned about the ability of making a proper, undersized replacement. (Not doubting your abilities, but it's a task above and beyond a lot of folks. But, not impossible of course.)

Perhaps bore the collar out slightly to make room for a thin bushing? Yes, the collars are hardened for wear resistance. I believe the tail shafts may have been carburized- hard on the outside with a soft core. I know the OD near the square can be quite tough. The square bore is hard where the u joint goes and the hardness on the OD may just be an artifact of the bore heat treat. Anyone have a factory drawing??

I was under the impression that the output shaft was hardened, and whenever I have had the need to dress the end where it runs in the fourth main I have had it ground to clean it up rather than machined. This is only done for the surface that runs in the fourth main.

Allan from down under.

The subject got me to thinking about hardness on areas of the drive plate. My testing method isn't to sophisticated. I do a file test.
I found the output plate shaft is not hard on the outer surface or inside the square drive hole. File cuts.
Dimensions are consistently 1.560" OD on unworn areas.
Several throw out collars measure 1.570" ID.
The throwout collar is harder than the hubs of ....