Redline MT90 Transmission Oil

The N16 manual gearbox is not the quietest and famous for whining especially during slow 1st-2nd gear traffic jam gear speeds Penang is famous for. Bloody irritating unless you crank up the ICE! With mileage now approaching 20K km it was time to replace the gearbox oil anyway and I looked around for a decent synthetic transmission oil that would help reduce the gearbox whine while providing adequate protection and minimizing transmission loss. Having used the excellent Redline 75W90 previously on the SP my 1st choice would again be from Redline. Will not be using the 75W90 on the Slowtra as it's rated GL5 and besides I would not be using the friction modifiers in the 75W90 as the Slowtra does not have a limited slip diff. Using the 75W90 would just increase gearbox wear. You have been warned! The service manual states that gearbox oil with 75W90 viscocity and GL-4 rating be used. Referrencing Redline's web page led me to the MT-90 which is the correct specification transmission oil for my gearbox. I settled for the MT-90 rather than MTL for the comfort of additional protection as the Slowtra is not a race car. Man this sounds like a condom or birth control advertisement! Those with auto-gearboxes can look elsewhere.

However it did take some time to order the MT90 as it's not common unlike the more popular MTL. Northern Garage ordered some for me (Thanks Ah Loy) and a stock of MT-90 arrived in about 2 weeks. The N16's big fat manual gearbox needs about 3+ bottles as one MT-90 bottle is listed at 1 quart (0.946 litres) thanks to the American's love of everything non-metric. This means that you have to order 4 bottles unfortunately. One bottle is around Rm55 so total cost is RM220. Definitely not cheap! Picture below of the MT-90 sitting in my room

Closeup
I had the Slowtra checked in yesterday (Sat) for tranny oil change at my usual workshop. Decided to skip TCEAS as I'm not partial to paying big bucks for a simple gearbox oil change. Only cost me RM8 labour at my usual place. Pix below of the bolt plug (in red box) which needs to be loosened to drain the gearbox oil.
Took some time to drain out all the gearbox oil. I would leave things for at least 30-45 min before refilling. Cleaned the underside of the Slowtra with healthy doses of WD90 during this time. Pix below of fresh MT90 being pumped into the gearbox. Car next to mine is my Bro CP's 200bhp Proton Satria Monster!

Driving home from the workshop the differences were instantly noticeable. Gearshifts felt slicker and the tranny whine is less but unfortunately not 100% eliminated. The downside is more pronounced tyre roar at slow speeds now. This means there is less tranny whine to mask the tyre noise. All in all a decent investment!