Spectator

iTrader: (1)

So, I went to the drag strip tonight. Ate everything up except a crazy **** with a suped-up Eagle Talon TSI.

Anyhow, waiting for my last race, Slowly comin to the starting line waiting for others to go, my car has trouble going forward. Let me explain, I release the clutch really slowly and its like if my emergency brake was pulled, so I give it just a bit more gas and release the clutch a bit more and then I hear a "TOK!" and then everything is fine and dandy. Wtf...Then doubting I should go down with the race, I do it anyway...Everything goes perfect except that my car starts to vibrate around 30 mph and increases vibration as I gain speed. Also, if I press on the gas the vibration gets worse and if I let go, it clams down, just like if the pressure on the drivesjaft was making it worse.

So what do guys think it is? Driveshaft, differential ( do RX7 diffs go out sometimes? Never heard of that.)

I havent jacked the car yet, I'll have to wait thursday.

Thank you

iceblue

More or less a U joint or broken rear diff mount

ramello

iTrader: (1)

+1 to that
i had a u-joint go bad and had real bad vibration issues that got worse with speed so sounds similar

although on a side note my mazdaspeed6 shuttered and vibrated like crazy today under hard acceleration and i found out coil 1 was bad causing a missfire.....not that its related but could be something similar?

1SxyRXy

word... sounds like u joint

Spectator

iTrader: (1)

What would a broken U-joint look like? I mean, to find out right away when I jack the car up.

AcidAngel7477

iTrader: (16)

just look at your driveshaft after you jack it up..theres one after the tranny and on at the diff..should be able to tell right away..but you might have to take the driveshaft off to see if the u joints are super loose, if they are. then the driveshaft is bad. you also might have blown an apex seal..does it shutter really bad on start up? and die after the cold start? could also be the diff. mount you might want to check that as well..and since were on the subject check the tranny mounts as well **** it im feeling froggy check the motor mounts too..

:AA:

texFCturboII

iTrader: (17)

i agree, probably a U-joint. If it is a problem with the diff mounts, when it;s jacked up, push up on the differential. If it moves, then it's a bad diff mount.

TehMonkay

iTrader: (-1)

You would hear clunking while shifting if it was a differential mount.

fastrotaries

You really have to get under there and look for cracks and such on the U joint. Also look for missing bolts on the driveshaft, tranny mount etc. Make sure everything is buttoned up.

Spectator

iTrader: (1)

Wtf!? No. The car shakes above 30 mph, nothing more.
You shouldn't say these things, if I were a noob and beleived these assumptions, I'd be scared shittless right now.

Anyhow, I'll look it up tonight...if I have time. The driveshaft is new, so the guy who made it probably made a mistake while making it.

MidnightOwl

My clutch master and slave cylinder wasn't bled correctly when I had to move my car around a few months back and it wouldn't engage until almost at the top of it's travel and it engaged hard with a huge TOK sound. I'm not sure if it's something that would apply to your situation, but it's another option. Bled it right the next day and the clutch was working fine, no TOKs.

Spectator

iTrader: (1)

No, my clutch disengages after 25% travel maximum. And it wouldn't cause my car to vibrate from the center. I'm pretty sure the rear u-joint is shot. What pisses me off is that its new.

boost_its_what_for_dinner

my rear diff. front mount went bad and it would knock whenever you shifted and cruising speeds with a load on the motor i.e. 5th gear on interstate(it was a na though)

Spectator

iTrader: (1)

It doesn't knock.

The car vibrates.

Period.

Red_Rabbit86

hmmm hey i kinda had a sound liek that a few months back scared tthe **** out of me. anywho now once in a great while it donest feel like its in gear plus if i let the car cost to a stop or just let it roll to decrese speed it tends to pulsate so maybe i have a bad u join or diff mount

Spectator

iTrader: (1)

Well, I found out what the problem is...I lost a bolt.

One of the 4 bolts that holds up the DS to the diff fell off. And thats what the TOK! was and why the car was shaking... It left its hole just sligtly, jameed against the diff casting and locked the diff. The added pressure of releasing the clutch broke it off and left a nice little mark on the diff casting.

Now my problem is...mazda. I called the dealer to get a new bolt but it seems that the washers are the weights that balance the DS. They have like 5 different available washers, 2.2 grams to 2.7 grams. Which one am I supposed to get? I never ever even bothered with that and never had any problems. I muist have changed them 6 times at least since I have the car and never bother to note where which one went. Just pulled the nuts off, put'em in a box, take them out and screw'em in.

So, how do I know which washer top get?

mxd

iTrader: (1)

4 of the same. to be safe, get 4 bolts nuts and washers.
Safety first.

Spectator

iTrader: (1)

I'm pretty sure you're wrong.

Is he?

Sorry

ericgrau

iTrader: (1)

I've never worked on the driveshaft before (and I know you love the noob advice you've gotten so far) but...

It sounds like those washers are weights to balance it, kinda like balancing a wheel. What weight(s) you get depends entirely on what you need to balance to minimize vibration. I suppose if you didn't care, you could just match it to the other washers. Again, I could be wrong.

It sounds like an undertightened bolt came off, or maybe an overtightened one broke off. I'd check the other 3 bolts for proper torque, but I highly doubt they're broken. And do you need to get a special bolt from Mazda? It would seem like any high strength automotive bolt would do. Then if you have a gram scale you could buy some washers of the proper weight. That'd save some money and you could replace the other 3 bolts just for kicks; even if it's unnecessary.

AcidAngel7477

iTrader: (16)

that is why i asked..never said that it WAS an apex seal..i said you MIGHT have..in any case its a good thing that it was what it was..

:AA:

AcidAngel7477

iTrader: (16)

:AA: