High speed rattle :S
 

hey guys,

I've got a techy here, I'm getting some kinda rattle up front at about 155-162ish km/h in 4th :S SKETCHY I KNOW, but, it goes away when I get out of that speed range and or if I shift into 5th, but, it isn't coming from my tranny, all my belts are tight, could it be aerodynamic something or others?

I wouldn't know if my car does it, I have never gone 162 km/h (100 mph) in my car, although it is smooth at 80 mph.

If it were aerodynamic issues, the car would do it in 3rd, 4th and 5th gear at the same speed (provided you would rev your engine past the redline in 3rd gear).

My (very wild) guess is that because it is a fourth-gear only issue (engine and drive shaft spinning the same speed), it is most likely a slightly misbalanced driveshaft and flywheel which cause vibration when moving in synch.

If it were suspension or brakes, it shouldn't stop in 5th gear.

I wish I could offer more suggestions, but this is all that I could think of.