Advice needed. Hum and vibration in 6th gear.
 

Hey everyone. Been reading these boards but first time post.

I recently bought a 96 Z28 6 speed. It is my first V8 and I am loving it over my previous V6.

I have been having a odd little hum and slight vibration come out of my car when in 6th gear though. The hum is a very slow and quiet in and out hum. I suppose I notice it only because I drive so much, most people in the car dont. It only happens when in 6th. Also, when I let off the gas in 6th I will get a slight vibration when I let off the gas, but as long as I am pushing on the gas even a little it will not vibrate. I am just wondering if anyone has any advice on this, or if it may be a tell tale sign that my engine is about to take a dive. I just passed 100k on it and recently replaced the clutch, although this was happening before and after the clutch replace.

Any help woud be great. I know enough to keep my car in good running condition but I am not too knowledgable about the inner workings of the engine.

I'm also saving up for new exhuast and headers. Just hoping my savings for that is not about to be blown on this.

Thanks
-George

I just noticed the same thing the other day. It's like a pulsing hum and it only happens in 6th when I am on the gas, if I let up off the gas it stops. Others dont notice so much but it bugs the hell outta me hehe Any Ideas guys? :bow:

Yeah, it is suttle enough that probably the only one who will notice is the primary driver of the car. Yours sounds exactly like what mine is doing, so it means at least I am not alone.

-George

Yours is the opposite of his? When you let up it quits but when you're on the gas it starts doing it?

no, same thing except his vibrates when he lets OFF the gas , mine doesnt. Both pulse when ON the gas in 6th gear. Any ideas?
:confused:

Probably the drive shaft.....my car use to vibrate(kind of pulse) in 6th gear at about 75-80mph. I put in a 1le drive shaft and the vibration went away.

Yeah it's your driveshaft. You probably don't notice it humming at low rpms at low speeds, just when your at low rpms at higher speeds. Get an aluminum or carbon fiber one and you'll be just fine. Plus the added weight loss should help you out some too. Atleast go get your current ds balanced and that should cure the problem. Hope this helps.

I think that it could be your u joints. Mine use to vibrate like hell when I was going down the interstate at around 70-80. As soon as I replaced the u joints it all went away. Also I always thought that my drive shaft was out of balance because I would get under my car and the u joints felt soild with no movement in them. Well when I finally took the drive shaft out you could instantly feel that there was a flat spot inside the ujoint itself. If they haven't been changed in 100k miles then that is where I would start. The u joints are $13 each and to have them pressed in is $10-$15 a piece. Definately a lot cheaper than replacing the whole drive shaft. Hope this helps.