high-pitched whine: 2000-2500 RPM

[gravyface]

In 5th gear, going about 80KM/hr, at 2000 and increasingly higher pitched until 2500 when it disappears.  No sound on deacceleration, only in top gear.

Probably nothing, but new sounds = scary to me.

[PumpItUp]

honestly, who drives in 5th gear at 80kph (50mph)

change the transmission fluid if you're that worried
tell me if you find any products which you add with the fluid that actually work for reducing tranny noise :confused: because i seen a lot at the store and i'm guessing they're all a crock of shit

[gravyface]

honestly, who drives in 5th gear at 80kph (50mph)

You're right: next time I'll drop it into 3rd and see if I can get the angry sewing machine to harmonize soprano with Robert Plant on Zep I, II, and III for the whole trip next time.

[nicknikolovski]

Usually some sort of bearing most likely in the driveline (gearbox to rear wheels). Could also be a slipping/loose drive belt/s.