when i am going 25mph or slower everything is good. When i hit 30 mph(doesn't matter what gear) I feel a vibration about mid cabin(driver/passenger seat). its bad at 30mph and starts to go away about 45/50 mph. Now like i said it doesn't matter what gear I'm in, i can put it in neutral and it still does it which leads me to believe it might be a rear axle. but i was also thinking maybe the drive shaft is loose? It doesn't affect the performance at all just kind of bother some. Any one have an idea?

 

Is your steering wheel shaking at all? Might need an alignment.

 

no its not shaking. I also thought it might be the wheels out of balance so i got them rotated and balance. but that didnt help

 

Check for excess play in the axles and the driveshaft

 

rotate tires front to rear, see if vibration changes.

sounds like one of the rear tire/wheel assemblies need rebalancing.

also, how is the wear on the rear tires?

 

Tell us what effect having the rear windows down has?

 

okay ill try the windows down thing. i had the wheels rotated and balanced about a month ago, and i will look at the tread wear.

 

The reason I ask about the windows is because my car has a vibration in the 50 to 60 mph range and it is much louder, actually rattles your eardrums, with the rear window lowered. I take this to be some sort of aerodynamic buffeting. This noise started about the time I replaced the worn OEM tires.

 

do you have an aftermarket exhaust? Check to see if any of your pipes are rattling against the driveshaft.

 

okay the tires are good all the way around. with the windows down it doesn't make much of a difference, but it slightly resembles a helicoptor. Im pretty sure there is no aftermarket exhuast, if there is its really quiet and i love it. I only had the car a few weeks before it went in and got a new clutch/flywheel and the tranny overhauled(brought to me by the warranty).

 

What kind of tires are on the car? Just because they look good doesn't mean the are good.

 

they are nexen N5000 m+s.

 

I'd be willing to bet the vibration goes away when you change tires. Did you see them actually balance the tires? What you describe definitely sounds like a tire issue.

 

Well I use to have a lil rattle at idle. Im thinkin its my xs downpipe tappin something. it wasnt that bad before but it was raining today and now the rattle is pretty loud at idle and goes away as soon as Im driving. Does the rain have something to do with it???

 

no i didn't actually see them rotate the tires. funny you should say that cause they didn;t even charge me for it. my thought was they thought i bought the rims from them or something becasue they were enkie. i guess i will wait till spring time when i change the tires out. thanks for the input.