Geiiga

This has been going for a while, actually, but it seems to be getting worse. It's my first rotary, bought it in July. Since I've had it, at speeds above 55, I'd hear a lot of excess noise when applying power. More recently, probably the past couple months, it's started shaking horribly. I'm not sure if it's the same problem or two different problems or if the loud humming noise at high speeds is unrelated. I took it in to a mechanic and asked if he could check to see what was causing that.

Came back, said the tie rods were bad and that if I didn't replace them the wheels were going to fall off, and that was most likely what was causing the shake. So, my wallet considerably lighter, I got back into the car, and it shook just as bad as it did before. They stood by their assessment and said that the U-joints had a little bit of play in them, but it shouldn't be enough to cause that kind of shaking and that maybe my driveshaft was bent.

Since it's started happening, it's been fine up to about 25 mph, then started shaking up to about 45, where it smoothed out up to 50ish, and then smoothed out again at 65 up to 73ish. And it's not just like a little shake. It rattles the change in my ashtray, I can hear things in the doors bumping around, and I feel like I'm having convulsions. It also only happens when I'm applying power--the only time it shakes while I'm coasting is the deceleration getting off the highway until I get under 60.

So what the hell's wrong with my car, and how expensive is that going to be?

Rx-7Doctor

iTrader: (13)

Is there a clunking noise when you 1st take off or under hard acceleration? Is the shaking coming up thru the steering wheel? Loud humming noise can be rear wheel bearing, bad diff.
I've seen loose driveshaft mounting bolts at the diff cause both symptons.. Bad U-joints will cause vibration in the drivetrain. If the noise gets worse as you increase speed then it could be either a front or rear wheel bearing.

Scott1982

Dumb question, but are your wheels on tight?
Control arms are okay?
You don't have any bent wheels or tires that have flat spots?
Rotate tires front to back to see if there is a difference?

That being said, it sounds like U joints could be bad or diff as others have mentioned specially if happening under power.

Scott

trochoid

iTrader: (6)

I'm 70 miles away from you. Bring it up to St Joseph and I can take a look at it for you. The 2 lane roads on the KS side of the river are a fun trip between here and Topeka.

Geiiga

Yes, but that just started Friday. There, too. Also up through my seat, into the rearview mirrors, and from the back.

j_tso

iTrader: (2)

anyone think it could be a bad transmission mount?

Nicholas P.

iTrader: (1)

warped drive shaft maybe?

trochoid

iTrader: (6)

Keep guessing there Nicky, in the meantime, please explain how a driveshaft could warp.

twinkletoes

iTrader: (17)

+1^

iwantjdm

i just had a similar problem, but mine was just a lot of vibration. not shakeing horribly. but my problem was the back ujoint in my drive shaft. i just jacked up the car and tried to turn the drive shaft while it was in gear with the parking brake on and i could move it. also when it moved it got pushed up so it was no longer in balance.

staticguitar313

iTrader: (2)

check your wheel bearings

$150FC

I have the same problem. Gonna check out the mounts and the driveshaft/diff on tuesday. How do you check wheel bearings?