986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Manual Transmission Fluid

Steve Tinker · 09-26-2011, 01:50 AM

There have been lots of discussions & opinions on this - but why would you replace the Porsche gearbox spec oil with something else?
Use the search function and I'm sure you will find many opinions on GL4 vs GL5 specs.....

For what its worth, my local OPC changed the gearbox oil (by my request) on my '01 Boxster S 6 speed when I purchased the car from them. They use Mobil synthetic 75W90 gear oil out of a 40 gallon drum & when I queried it, the tech said it was "as good but cheaper than the Porsche stuff" - I believed him.

Fast forward 3 years and 10,000 miles later, last June I replaced the gearbox oil with the genuine Porsche lubricant as I was not happy with the notchy cold shift action. The difference was immediate after the first cold start - the Porsche lube is superior to the Mobil product in all temeratures !!
I will not go back to aftermarket gear oils again - especially as you only have to change it every ~90,000 km anyway.

09-26-2011, 01:50 AM	#2
Steve Tinker Registered User Join Date: Dec 2008 Location: Queensland, Australia Posts: 1,522	There have been lots of discussions & opinions on this - but why would you replace the Porsche gearbox spec oil with something else? Use the search function and I'm sure you will find many opinions on GL4 vs GL5 specs..... For what its worth, my local OPC changed the gearbox oil (by my request) on my '01 Boxster S 6 speed when I purchased the car from them. They use Mobil synthetic 75W90 gear oil out of a 40 gallon drum & when I queried it, the tech said it was "as good but cheaper than the Porsche stuff" - I believed him. Fast forward 3 years and 10,000 miles later, last June I replaced the gearbox oil with the genuine Porsche lubricant as I was not happy with the notchy cold shift action. The difference was immediate after the first cold start - the Porsche lube is superior to the Mobil product in all temeratures !! I will not go back to aftermarket gear oils again - especially as you only have to change it every ~90,000 km anyway. __________________ 2001 Boxster S (triple black). Sleeping easier with LN Engineering/Flat 6 IMS upgrade, low temp thermostat & underspeed pulley. 2001 MV Agusta F4.