ive got bad vibration at high rpms

donkey_punch said:

i notice that you did 3:73 gears. did you get an aluminum drive shaft?

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Good catch. When revving in neutral, the driveshaft doesn't rotate. Basically, all metals have a rotational frequency. At least, I think that's what it's called. When rotated at a certain speed, the metal flexes more; that's the vibration. When upgrading to 3.73 or 4.10 gears, you reach the rotational frequency of the stock driveshaft and you get vibration. It may not be noticable at first, but the extra vibration puts s bit more stress on the u-joints. The vibration can show up later on. Usually, you won't notice the vibration until you're at freeway speeds - the driveshaft won't spin fast enough on the street.

An aluminum driveshaft has a much higher rotational frequency, so you'll likely eliminate the vibration by getting an aluminum driveshaft. Did the vibration show up right around when you got the new gears?