Gear oil for '89 Porsche

[Big Dave]

My '89 Porsche Carrera (911) is due for a transaxle oil change. Manual calls for GL-5 75W-90.

I've seen some good write ups on Royal Purple Max Gear Synthetic 75W-90. Is this any "better" than M1 75W-90 gear oil?

What about Mobil Delvac Synthetic gear oil-75W-90. I think this is the replacement for Mobilube SHC that was recomended by PCNA.

David

 

[unDummy]

M1 75w90 isn't the best choice for manual transmissions.

Try the RoyalPurple or Delvac.

Its difficult to find a perfect fluid that'll make LSD's happy and allow the synchros to work without notchy or crunchy shifts. Trial and error!

 

[ccs v2.0]

Swepco 201 (80W90 though). Don't overfill.

 

[ediamiam]

I agree with Swepco 201. It's what I use in my '67 912, 5 speed.

 

[Big Dave]

My transaxle does not have LSD. The Swepco 201 I believe is more indicated for the type 915 trans. My '89 has the type G50 trans.

I'm going to give the Royal Purple Max Gear 75W-90 a try.

David

 

[unDummy]

With no LSD, gear oil selection opens up and becomes more easy.

Nothing wrong with RP, or D1, but some more to try:
Neo 75w90HD
Redline 75w90NS
Motul Gear 300
Idemitsu racing 75w90
Silkolene Silktran SYN5
Castrol Syntrax
Synlube MT
Lubro Moly Voll-Synthese Gear Oil

 

[jonny-b]

unDummy, I am impressed that you seem to know about Synlube. I have ordered Synlube for my Automatic transmission and the engine. I am excited to see how it performs. I have been at their webpage and actually been reading most of their info. I like their page because of all the information you find there. I have tested their powersteering fluid, and it did perform well, that is why I have ordered their products again. If I have understood things correct, they seem to have the only oil on the market that is 100% synthetic. This is one of the main reasons to why it outperforms the others.

 

[benjamming]

What testing did you do of their power steering fluid? Can you post some results on BITOG or point me to the link on here where it was previously posted that I must have missed?