Where do I start... I used to run penrite oil in the 'T' before it blew up, now I have the FG F6 short motor in it and it's done roughly 10000k's. We ran it in on Castrol Magnetic for the first 1000k's, changed the oil and filter, and I was putting off changing the oil untill now as this week I'm off travelling roughly 1500k's in a weekend, and next week I'm heading down to Hervey bay where I'll be getting a tranny service done, and the centre diff bush replaced along with a couple of other little niggling things, all up it will be about a 2500k round trip. So, I bought some Nulon 10w40 and a new filter, did my usual 45min service and checked that everything under the car was sweet before the trip, and upon start up the car seemed quiter, yeah oil can do that. Then, I shifted into 'D' and no noise at all from the tranny, went for a drive and the car seemed a LOT quieter to the extent that I could swear even the exhaust note at 60kph was quieter. Put my foot down and brought it into boost, and the turbo seemed to sound nicer too... Anyhow, I picked up the missus, and she notice that the transmission didn't 'clunk' like it always does, and when we were driving se said "the car sounds quieter today, what have you done to it now". As if to imply that I spent more money on it without her knowledge. I haven't smoked any hooter, I've not been drinking for the past 6 days, and I haven't bumped my head recently (to my knowledge). Can an oil and filter change really do this, or have all our little problems somehow been realted to using a cheaper oil?