i'm starting to get a lot of vibration at freeway speed and i'm suspecting my driveshaft. vibration occurs whether the clutch is in or out and is really bad around 3k rpm in all gears.

if i pull it off the car, what can i look at on it to determine if the u-joints are bad?

thanks,
john

 

Check the u joints, front and rear to see if any play. You should be able to check with driveshaft in place. Get under there and hold before and after joint and twist, lift, pull, to see if any play. Check trans mount also.

 

Could it be the tires?? My drive shaft is going out too but is not making the car vibra. The only thing my shaft is doing is make clanking noise when i shift at low rpm and speed. I had a friend that had the same problem we never figura out what it was. But i post the question before and someone suggest that it might be the fan clutch if the all tires and stuff was good. And does vrbration go up with RPM??

 

twisted - does your driveshaft sound like someone whacked your car underneath with a hammer (like a rubber mallet on metal)? like a TOONK sound? i get that noise now and then when i'm letting off the clutch at a light.

the vibration seems to build up at 3k rpm, then settle down a bit. feels like i have a back massager on my seat.

i will get the wheels checked out since that's a simple and cheap fix.

john

 

Been throught two diveshafts on two different '90s. Different symptoms both times. The first was the classic "Clang" when engaging the tranny. No vibrations at all when driving at any speed. Mazdatrix write up on drive train claims that a clang when shifting into low gears is the front U joint and in high gears the rear joint.

The second and most recent was a vibration that began over 60 MPH but absolutely no clanging at all. Felt vibs in steering wheel and shifter. The vibration began at lower speeds the more it was driven. Got worse over one week period with infrequent driving.

I'd first have the wheels checked for balance before we say the drive shaft is the culprit. Might also be the wheel bearings.

 

check the alignment of your rear tires. Also, it is my understand that if your rear schocks are bad it could manifest into the problem you are having.

 

thanks for the extra ideas guys!

 

Have you done anywork recently on your driveline? Pulled the drive shaft for any reason? Sometimes drive shafts have washers on them that are there to help balance, if you took off the driveshaft but forgot to mark where those washers went, it could unbalance the whol shebang.

Steve

 

we did pull the driveshaft out a while back...but that was a good 3k miles ago. this vibration appeared overnight pretty much. and with 225k+ miles on the tranny clock, i'm not overly surprised if stuff's starting to wear out.

john

 

final result - took the car in to the local rx7 guy and he said the driveshaft is bad.

john

 

Selanne8 - Glad you got it figured out.. Unforunatly new drive shafts are a tad expensive. you can bitch about mazda putting in non-replaceable u-joints, or just be impressed that their engineering held together for 225k+ miles (like they did on my car)

TwistedDriver - I'd get that driveshaft looked at.. it's a potentially dangerous problem when the driveshaft starts to get loose. I've heard of them coming off/apart and through the floor of cars, and other nasties.

 

thanks for the concern, but i am trying to get rid of all the oil leaks first. I know that is not the most important but is bugging me. Drive shalf rebuild or a new one is expensive but i am working on saving some money for it. PLus it think is just a little lose right now so i think i can get a way with using it for a few more thousand miles, if not hundreds. BUt once again thanks for the concern!

 

They are expensive. I replaced mine with OEM from Mazdaformance ($279+ shipping). You can also get a driveline shop to install replaceable u-joints for about the same.

 

Here's the deal on driveshafts -

NA driveshafts do give up after a certain point - it's usually felt as very bad driveline vibration, and you'll often get different vibrations as you're on and off the gas.

It's damn near impossible to determine if a driveshaft is bad with it on the car. You can't even see the first U-joint with the exhaust on the car, and once you get the exhaust off it's four more bolts to pull the driveshaft.

With the driveshaft out, it's REAL obvious if the U-joints are bad. The U-joints should flop around like a universal joint you use with a socket set - if it's real hard to move one direction or the other, or if you see obvious damage, it's bad.

TurboII driveshafts NEVER go out - I've yet to see a bad one. Dunno why. And, no, you can't use it on an NA .

I usually just look for a good used driveshaft - picked one up for my wife's car for $20-30.

Also, if you get a big clunk/whump when you take off in 1st gear, it's quite likely your differential mount is broken. Easy way to tell - get moving in 1st gear, then pump the gas pedal. If you hear it whumping each time you pump the pedal, that's the diff mount hitting the frame of the car. The Mazdacomp replacement is only $60-80 brand new, and makes a HUGE difference.

Dale

 

wonko - funny, my car just reached 225k also :-D i went with a mazdatrix aftermarket one...not as pricey as the oem mazda shaft and mazdatrix sells the replacement u-joints for about $20.

dcf3cs - maybe the turbo ones don't go bad cuz most turbos don't reach 225k miles...or at least i haven't seen any incredibly high milage t2's.

john