3 hours ago, dutchzcarguy said:

And ofcourse this oil is no where to be found in Europe.. the Netherlands to be specific?  Is it General Motors ac delco 75W90 or ??

i see 10-4016 75w90 is a pure synthetic and an other one which i forgot.. i went to amazon.nl (netherlands, typed in: ac delco 75w90 and..... i got a Bosch filter... yep.. thats amazon in the Netherlands....pffff... never have and prob. never buy from amazon overhere. duhhh..

I recommend SWEPCO 201 for use in Servo (Porsche patent) synchro 'boxes. The proper Porsche specialists in NL should be able to supply it, but here's a UK-based supplier:

https://type911shop.co.uk/epages/de867ca1-377e-432e-84fd-bdccf2206766.sf/en_GB/?ObjectPath=/Shops/de867ca1-377e-432e-84fd-bdccf2206766/Products/2042

8 hours ago, dutchzcarguy said:

And ofcourse this oil is no where to be found in Europe.. the Netherlands to be specific?  Is it General Motors ac delco 75W90 or ??

i see 10-4016 75w90 is a pure synthetic and an other one which i forgot.. i went to amazon.nl (netherlands, typed in: ac delco 75w90 and..... i got a Bosch filter... yep.. thats amazon in the Netherlands....pffff... never have and prob. never buy from amazon overhere. duhhh..

 

Apparently Pennzoil developed the "synchromesh" formulation for GM.  So if you can find Pennzoil Synchromesh, it's the same formulation, as the internet seems to show.

But, for whatever reason, maybe because a copyright wasn't acquired or not enforced or because GM let the formulation data out, there is a "synchromesh" for several other brands of oil.  And a "Synchromax".

https://www.amsoil.com/search/?text=synchromesh&timezoneOffset=420

https://www.valvoline.com/our-products/grease-gear-oil/synchromesh-mtf

https://www.pennzoil.com/en_us/products/other-oils-fluids-fuel/manual-transmission-fluids-axle-oils/synchromesh-manual-transmission-fluid.html

https://www.royalpurple.com/product/synchromax-manual-transmission-fluid/

 

And, on the Porsche synchros, there are several discussions about steel baulk rings in the early 5 speed Nissan transmissions.  Another side thread.

JMortensen said he used to work for a shop that used Swepco 201 for those in the Porsche transmissions, and a blend of Swepco and ATF for the "brass" Nissan rings.  I used the blend on an old 5 speed ZX transmission that had problems with Redline and it fixed it.  It's spendy but good stuff.  Most Porsche racing shops will have a 50 gallon drum of it in the shop.  That's where I got mine.

https://www.classiczcars.com/forums/topic/19361-gearbox-oils/

https://www.classiczcars.com/forums/topic/19261-early-5-speed/