(Realised I posted this in engine building forum by accident so posting here now)
I'm setting up a transmission for someone... (I don't normally work on transmissions) The box is a bit of an unknown quanity.
915/72
Bearings bores are actually nice and tight.
It needed
- replacement pinion and crownwheel (original was damaged)
- new gearsets for 2nd and 4th
- all new dog teeth, syncro bands, sliders
- all new bearings
This is the first trans I had pulled apart with only 1 shim (0.2mm).
The old pinion didnt appear to have an N number.. but the matching crownwheel had 66.63 etched on the side, next to the backlash number.. this may or may not be relevant.
The differential carrier was also pretty worn and the carrier bearing on the cover side, had been spinning on the shaft, so we sourced a replacement diff carrier.
So I'm at the setup point. I'm armed with the porsche manual, the Wiki from P Zimmerman, and also the excellent videos online by ************ (but his stuff seems to just work out perfectly every time!)
First thing I went to check, was pinion depth.
The pinion shaft (and input) was assembled in the housing, and torqued to spec so the big nut was tightenting everything down. Note, I did this without installing any shims.
For measurement, I am using a VW289 tool that I bought from Evan in Norway who also put up a thread here.
The tool was supplied with a gauge block and the tool is scribed with 58.69mm. I assume this means that when zeroed, the dial gauge is reading 58.69 from the centre of the rotating axis to the tip of the pointer on the gauge surface.
Evan had supplied it with two specially made spacers (7.61mm), so that when the dial gauge is zeroed, it is reading 63.30 mm. (58.69 + 7.61)
The tool is inserted, the side cover fitted and torqued down, the tool has no axial or lateral movement.
When rotating to the face of the pinion, it is giving me a reading of 0.2mm. So I believe that means, that with the 63.3 + 0.20 = 63.5mm is where my pinion setting is without a shim.
Now, the N number on my pinion is 0.22. So that means the desired deviation is 63.3+0.22 = 63.52.
So that means, that without any shims, I am 0.02mm away from ideal spec but within +-0.03 tolerance.
Not sure I am using this correctly...
Has anyone ever come across a gearbox that didn't need any shims under the bearing retaining plates?
