seventhgear

it starts at 40mph.
then slowly get worse at higher speed. motor mounts? drive shaft? something maybe not tuned right.? anyone have any feed back? it will be greatly apreciated. its getting worse everyday.
thanks again
jack

mazdaspeed7

driveshaft

Evil Aviator

It could be the tires/wheels, but it's probably the driveshaft u-joints binding. The only way to check the driveshaft u-joints is to remove the driveshaft from the car and see if you can move the joints by hand. If you need to pound on the u-joints to move them, then they are toast, and you need a new driveshaft. See the Factory Service Manual on how to remove the driveshaft (Mazda calls it the "propeller shaft"), paying special attention to the part about marking the flanges and balance washers prior to removal. Also be careful to lower the exhaust system carefully and evenly, as the exhaust tips tend to break off if the front or rear falls to the ground.

BTW, Scott's Sport got its initial interior gutting via a bad driveshaft that suddenly locked-up. This is not a good thing.

seventhgear

well im gonna change my tranny tomorrow night. and i have an extra driveshaft thaT i was just gonna swap and see if that did the trick. thanks guys. i was thinking tired too but it stopped when i let off the gas so i ruled that out. all i could think was d-shaft/tuning/mounts.
well if n e one has n e other comments or experiences i would like to hear them . thanks EVIL & MAZDASPEED7
jack

Xentrix

if it isn't the driveshaft it is most likely the wheels then. A quick check is to grab the wheel while still on the car and push it. If you've got a loose wheel bearing you'll feel a clunk.

Hope you get it fixed.

poor college student

when you push it, are you tlaking about when it's on the ground...? or after u jack it up? u know what's weird, when my car's jacked up, it kind of looks like the wheels aren't on straight....

ARD T2

iTrader: (22)

Yeah, I think driveshaft and trans mount

bingoboy

check all your tires bud, maybe you have a chewed up thing. i had a car that had bad vibration at speeds like yours...by 70 it was unbearable. i found a tire that had a bulged chewed up spot on it that when replaced fixed the vibration.

like cuz the shocks push the wheels down farther than they sit normally and give you a wacked out camber? heheh

GLHS

Normally you can hear a clunk or a click when you give the car gas if the u joints are bad.. The GXL had a bad u joint and made those sounds....

Check and make sure the balance weight is still on the driveshaft.. I have seen them fall off and create a nasty vibration thats just gets worse the faster you go.

It should a flat metal peice welded on.

seventhgear

i know i was listening for a clunk while i was driving. but only sometimes i could hear it. maybe because my car is loud i dont know. didnt sound too bad though. like i said it only does this whilegas is depressed.if i let off it gets smooth. thatz what ruled out my tires. so man this **** is pissing me off. thanks guys
jack

Xentrix

you shake the wheels when the car is on the ground. you'll feel play in the wheel and it sorta clunks if you've got loose wheel bearings, there's a writeup on www.fc3s.org on how to fix it.

seventhgear

im hearing major clunking now through shifts. DRIVESHAFT

GLHS

Does the sound happen when you shift real slow?

Does it sound like its hitting the underside of the car?


I have a good driveshaft, we could trade something for it..