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DIY 915 gearbox tools


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I'm currently making some 915 gearbox tools for my gearbox rebuild, does anyone have the dimensions of Porsche tool P355A.

From the photo below I was going to start with a 100mm length of 50mm x 16mm flatbar as a starting point.

If someone could supply the internal dimensions of P355A in relation to the attached drawing, that would help me out.


4260012987_307f0f1e79.jpg     442798.jpg

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18 hours ago, AdRock said:

Can you just measure your 915 Main shaft? Assuming that you're building this tool to rebuild your own transmission.


You are correct in saying that AdRock, but the Mechanical Maintenance Planner in me lives by the 6 P's mantra. So if all else fails I will have to wait and measure the shaft after disassembly.

But I'm hoping someone will be able to assist with the dimensions of P355A.🙏




6 P's: Prior Planning Prevents Piss Poor Performance.

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  • 2 weeks later...
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Finished the P252A tool this week. I used a section of 1-1/4" gal pipe, a 41mm socket for the mainshaft nut & an old 1/2" drive socket for the tension wrench end. I also made a variation of the P252A that I saw on the Pelican forum, using an old 41mm ring spanner & an old 1/2" drive socket.

I will be starting to fabricate the P37A next week now that I have acquired some old clutch plates for their spline section. After failing to find an old used 915 style clutch plate, I sort out some help from a mate in the auto spare parts field. After figuring out that I needed a 20 spline x 22mm I.D. type clutch plate, we were then able to determine that an early Ford Cortina or Anglia had a clutch plate with 20 splines and an I.D. of 7/8". 






P252A pelican variation:



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I started on the P37A last night, the Ford clutch plate is a perfect fit to the 915 input shaft splines(who woulda thunk it 🤦‍♂️).


This is the start of cutting up the Ford clutch plate, sacrilege for some I'm sure. I'll machine off the flange plate from the spline boss section next week at work.


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I completed my P37A tool for the 915 gearbox this week, I probably spent 1/2 hour each day after work to finish it. I'm thinking of making an additional bolt on piece out of angle iron, to bolt onto the bell housing stud holes so that the P37A tool can be held in a bench vice with the gearbox shaft out of the gearbox.


Cutting out the raw material, 10mm steel plate was used.


Machined the remaining part of the clutch disc off the spline boss on our old little jobber lathe at work.


Spline boss with extension welded onto bell housing brace.


Tapping 10mm metric course threads for the bell housing studs.


I had to straighten the brace because of some heat distortion from welding.


Ta da, my version of the P37A.


Fits on the 915 just like a bought one.😀👍


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Hey PFAer's,

Can anyone assist with the dimensions of 915 gearbox tools P225 & P226?

I'm considering making these 2 tools as well for my future gearbox rebuild, so any help would be greatly appreciated. These 2 tools will be more of a challenge than my previous gearbox tool making adventures.


P225: 915 3rd, 4th & 5th gears.


P226: 915 1st & 2nd gears.


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