[Jim Sims]

"No, this is where you have the input shaft stack
out of the intermediate plate and need to loosen or tighten
the 32 mm nut using P252 or equivalent. The P256 or
equivalent is fixed in a vice so the input shaft assembly is
vertical. This allows you to use both hands on the wrench
and P252 to not put any bending moment on the input shaft.
The Factory Workshop Manual (FWM) shows this operation
with the shaft horizontal. I believe this contributes to the
failure of the input shaft at 1st gear."

For the 915 version of this tool I used an old clutch disk in which I drilled out four of the existing holes and inserted bolts; on the other side I screwed onto the bolts, long coupling hex nuts and tightened and shimmed them so the flats were parallel to each other. The disk is then placed in my large, heavy duty bench vise clamping onto the four coupling nuts with the axis of the splined hole oriented vertically. This permits the gear stack/input shaft to be vertical while the nut is being loosened/tightened. One person typically mans the custom socket (equivalent to P252) with the breaker bar or torque wrench and another supports the shaft against the reaction. Even vertically it is difficult to achieve pure torsion without some bending moment.

My Porsche mentor took my modified 915 clutch disk and cut off the old friction disk portion (leaving only the center core) to make it more compact and he further improved it by welding a cup underneath (with a punch knock out hole if the shaft becomes stuck in the splines) to support the end of the input shaft so it engages the clutch disk splines at the correct location and not fall through the modified clutch disk. Can we not make something like this for the 901? Scrap 901 transmission parts may not be too common around here. I'll post some images of the modified clutch disk tonight.


Thanks again, Jim