wtk - slight rumble at 90 kph in 4th gear

[undercover]

any ideas on the cause of the following -

if i accelerate through the dial, at about 85 kph i start to feel a slight rumble through the cabin of the car, increasing slightly as i get up to 90 kph, and slowly dying off after 95 kph. the rumble is not constant one, but more of a pulse (maybe 1 second intervals), indicating to me it's caused by some rolling movement. it sounds as though it could be coming from the drive shaft or gearbox. now this only happens if i pass 85-95 kph in 4th gear. if i pass 85-95 kph in 2nd, 3rd or 5th, there is no vibration at all.

any reason why this may be happening, and in 4th only?

thanks in advance. the car is rwd btw.

[carryman88]

ummm.....1st question...what kind of car are we talkin about.....2nd question is u pass 85 to 95 kmph in 2nd gr????
3rd....does ure steering vibrate at all during ure "rumble"

[undercover]

1. it's an rs200 altezza.
2. i redline at 7800 so yes, 90 kph in 2nd
3. no steering vibration at all.

[undercover]

any advice on this?

[turbohead]

drive shaft center bushing, cross. do a visual under the car an see if anyting is loose

[wagonrunner]

question is u pass 85 to 95 kmph in 2nd gr????

that's strange to you?

[undercover]

I already took off the drive shaft and had the cross on both ends changed. The mech didn't say anything about the condition of the center bushing though... can these be repaired or do they have to be replaced altogether?