Vibration at 3100 RPM..anyone have this problem?

[1BAD93]

Doesnt matter which gear i'm in once the car has warmed up i get a vibration/hum that lasts from 3100 to about 3400 rpm. It feels/sounds likes it comes from the middle-rear of the car but i'm not really sure. It seems to have started a couple months after i installed a catted mac prochamber. I'm thinking it may be a bad cat or maybe its just the sound the prochamber makes and there isnt anythign i can do about. Any ideas.

Joe

 

[Kilgore Trout]

Could it be the driveshaft? Did you remove your dog bone?

 

[1BAD93]

No i never removed the dog-bone. I should check to make sur eit didnt fall off. If it is the driveshaft what are my options, aluminum replacement or can it be balanced?

 

[Kilgore Trout]

If you removed the driveshaft did you mark it so it went back on correctly?

 

[1BAD93]

I never removed the driveshaft? or the dog bone? Only mods are catted prochamber, magnaflows, and a K&N FIPK

 

[COramprat]

Is this while moving or just idling?

 

[1BAD93]

This is while moving. Its even more pronounced under acceleration load..but you can feel it during decel as well while going though that RPM band.

 

[COramprat]

Probably a bad U joint. Crawl under the car and see if there is any excessive play in the joint.

 

[1BAD93]

Thanks. I'll have to check it when i get out of work. Any idea how muhc play is excessive. If i try and move the driveshaft there will be play from the transmission but how can i specifically check the u-joint

 

[COramprat]

Try to move just the knuckles of the joint. If they move any you need to get a new one.

 

[1BAD93]

The rundown on my bad DS was at around 2000rpms I would get a real deep moan that resonated throughout the car. Like a subwoofer with a steady hum. I would do it in each gear and at about the same rpms.

I just read this post you made on another thread. That is the exact way i would describe the sound. I tried getting under there to wiggle the u-joint but it really didnt move. What did you do to fix yours..did you replace the driveshaft or have it balanced?

 

[HoustonGT]

I just read this post you made on another thread. That is the exact way i would describe the sound. I tried getting under there to wiggle the u-joint but it really didnt move. What did you do to fix yours..did you replace the driveshaft or have it balanced?

Bah! That explains the damn sound i've been getting lately with my vibration.
how much is it gonna run me for a new u-joint and driveshaft balance?

 

[1BAD93]

I'm wondering the same thing. An new aluminum one will run 270

 

[HoustonGT]

I'm wondering the same thing. An new aluminum one will run 270

Yea i'm just wondering if the aluminum driveshaft is worth that much. I remember about 2 years back when that sucker was like $159 and then the price of metal skyrocketed and so did the cost of the driveshaft and all the exhaust systems as well.

 

[Kilgore Trout]

I got an aluminum driveshaft by trading my GT for a Terminator...

 

[COramprat]

I just read this post you made on another thread. That is the exact way i would describe the sound. I tried getting under there to wiggle the u-joint but it really didnt move. What did you do to fix yours..did you replace the driveshaft or have it balanced?

Yea...bought an aluminum one for $159 Now you have to add a hundred.

If you have a bad u-joint just get a new one. Not hard to swap out and they are about 35-40 bucks I think.

 

[Mustang5L5]

One PITA way to find out...swap the stock pipe back on

 

[the98stang]

It's most likely the exhaust.

The U-joint will hold up for quite some time unless you've messed with the DS before