mmasse

i would like to buy some Porsche special tools required to rebuild the transmission.
000.721.928.60 Retainer plate
000.721.928.30 assembly bush
000.721.928.40 puller

Does anyone knows where can I buy them?..do regular dealers carry special tools?

My other questionis, are these usually very expensive?...They are actually very simple tools

Thanks

springer3

I have the tools needed to rebuild a 901 transmission. I don't know if they work on the G 50. Setting the pinion preload is a bit of a trick on the 901 boxes. I suspect the G 50 is the same.

I am willing to loan tools if you can confirm they work. I would need a deposit large enough to cover the replacement cost.

mmasse

Springer3,

Thanks a lot for the offer. i will try to find out if they work for my transmission. Do you know the part numbers of your tools?

Any specific hints on the process for setting the the pinion preload?

Thanks again,

Bill Gregory

Dealers can typically order any Porsche tools for sale.

springer3

I will look on my tools tonight, but I don't recall seeing a part number. They may be "knock-offs", but I did successfully rebuild several 901 boxes with them.

I don't know how the G 50 ring/pinion pre-load is set, but Porsche does not change things that work as they develop new models. On the 901 box, the preload is set using paper shim/gaskets between the intermediate plate and the main transmission housing. The factory tool is a fixture that bolts into the differential housing, and provides a reference to measure the pinion position. Most mechanics I called don't have the special tool, and instead measure the old shims and install the same thickness new ones. That is a no-no if the bearings are replaced. Slightly loose or tight and you get gear noise. Way loose you can break a gear. Way tight and you can burn up the gear set.

There are some DIY possibilities, but I did not pursue any because I found a professional with the tool willing to set the preload the factroy way. The purpose for the pre-load is to ensure the driving force is located at the center of the helix of the ring, and the center of the helix of the pinion. That is the sweet spot, where things are strongest, and the best combination of rolling and sliding contact occurs. The sweet spot keeps friction low, and minimizes gear noise. Two DIY approaches:


1) Study the factory location tool, and find alternative measurement system (not easy, unless you have access to pecision measurement tools).

2) Spray a very light coat of machinist's blue (oily paint) on both gears. Assemble the transmission with best guess of the correct shims. Roll the gears under driving direction load. Look at the scuff marks in the blueing that reveal the contact location. Add or remove shims as needed to get the contact point in the center. This would be a tedius method, but should get you at the perfect preload - possibly even better than the factory method as you observe the desired result directly.

I never tried a DIY method - potential for breaking a transmission drove me to the factory method. A bad guess could lead to disaster. If you can locate the special tool, it is the way to go. Good luck.

mmasse

Question about the pre-load.

i do not plan to copmpletely rebuild the transmission. I will only change the synch ring for the for gear.

Do I still have to bother about this procedure? From the manual I understand that i only have to readjust the pre-load if disamble and replce parts on the differencial...or are you talking about something else??

On the tools.
Unfortunately, i was not able to confirm the issue on the tools. I asked to Pguys I know and they have no clue. Below are the tools that i would require for the job. Could you tell me if they look like the ones for 901?

Thanks again

springer3

Nothing looks even close. It looks like Porsche changed the design. If you are not changing bearings, and you keep track of all shims, you should be able to avoid upsetting the pinion preload. If it were me, I would still want to know everything was ship shape while the box is out of the car and already open. It took the mechanic less than 30 minutes to set up and adjust the preload on a 901 box.

mmasse

Thanks anyway for you intention!
I will post the end result of this. I hope it is possitive :-)

Cheers

JasonAndreas

What pages in the workshop manuals are you looking at? 39-13 for C4 & 39-211 for C2 cover adjusting the drive set and setting preload, etc. and it looks like a lot more (17) tools are required.

mmasse

The tools I posted are those needed to disassembly the gear box.

My question was if I have to worry at all about adjusting the drive set, since i do not plan to completly disassembly the transmission. I will only take out what is needed to replace the 4th gear parts.

Any thoughts?

Thanks

JasonAndreas

What ended up happening with this? Did you go through with the rebuild? What tools did you end up needing? Can you do this without having to re-adjust the drive set? Any pictures?