zilch321

I'm currently seeking out and trying to fix all the vibrations this poor car seems to have. The car is 100% stock.

I'm getting a vibration starting at about 50MPH. With the car sitting still I can run thru the RPM range with no vibration so i'm thinking it must be further back.

Brakes are in good shape and so are the rotors and other wheel related bits. I'm not getting any vibration in the steering wheel and i'm not getting any vibration in the brake pedal.

While I was under the car this evening i did get my hands around the drive shaft on the Diff end and gave it a wiggle. It seemed very solid to me but I didnt get a chance to grab hold of the transmission end.

While i've done suspension/brake and engine work the driveline and transmission are new territory for me. Could the drive shaft feel solid on the Diff end and have play on the tranny end? OR should I be looking for something else.

Thanks for all your insight. BTW car has 149K miles.

-m

slo

iTrader: (1)

the drive shaft U joints should be flexible not tight or notchy

tires balance?

cptpain

iTrader: (1)

being that you said the car is 100% stock, it might be time to replace a few things....hmm?

while you were at the driveshaft did you check to see if the balance weight was still there? it looks like a small plate attached to it.... if you cant find anything like that along the length of the driveshaft then that might be the problem. happened to me last summer, and again a few months after getting a new aluminum shaft...

zilch321

I'm going to give a good look at that shaft tomorrow. Now that I have some idea of what i'm looking for (weights) and shaft play. There is a chance the tires are out of balance but the previous owner have new tires put on right before the sale. When checking out the brake system I noticed that all the wheels did have weights attached. Doesnt mean they are correct but it might be the newest item on the whole car

Thanks folks, i'll try and post what I find until I get some closure in case others have similar issues.

-m

zilch321

Ok, well at lunch i put the car up in the jack stands and had a better look at the drive shaft. Yay for working from home.

I didnt see any play in the shaft. I couldnt really tell what was up as far as weights go. There was a small longish looking tab on the drive shaft on the tranny side but I couldnt tell if thats the weight I was looking for or not. Looking at the service manual they mention balance washers but I didnt see anything about weights for me to reference against the shaft.

I should probably get some Raleigh area RX7 gear heads to check out the car and tell me what they see. I saw some rather craptstic looking front bushings which were still in tact and I saw some rather clean looking front transmission bushings (maybe recently replaced).

Maybe a second person in the car could help pinpoint the issue.

darktritium

To be honest, I don't think I had any driveshaft play either, but my tranny-side U-joint was shot. Shot as in frozen; it only moved in one axis back and forth. Pulling out the driveshaft is probably going to be your best bet just to check it. The symptoms in the PM you sent were what I was experiencing. In fact, I JUST helped out (hopefully helped) someone who had driveshaft issues too except he was going to be making a trip from here to Florida soon.

zilch321

Right now the todo list is to have the local tire shop check the wheels to make sure everything is balanced out OK. If so i'll attempt to get the rusty exhaust off and get that shaft out for a full inspection. Good chance you are correct, I didnt see any play in the shaft - maybe thats because its frozen - not sloppy. I've done a lot of forum searching and most of what I see people complain about is slop. Frozen Ujoints dont seem to turn up very much.

inflatablepets

I too suffered from the driveshaft plague until 2 days ago. When I checked, the little needle bearings were sitting on the heat shield. It sounds like that's what's wrong, and it will get much worse if you let it go.

zilch321

Dont like to leave threads hanging open so I wanted to confirm, I indeed had a frozen Ujoint.

So for those searching this later, sloppy drive shafts are bad but it appears you can also have Ujoints freeze up on you. I for one wasnt aware of this fact. My Diff side joint seemed Ok it was solid but workable in all directions. My Trany side ujoint would turn in two directions (call it up and down) but wouldnt turn in the other two directions (call it left to right).

Thanks to everyone who gave input. I'll get myself a new shaft ordered tonight.

--m

darktritium

Awesomeness. I'm glad to hear that you fixed it! As I'm sure you know, installation is the reverse of removal. Also thought that maybe you should get some gear oil to put on the tranny-side input shaft.

zilch321

With the car already up on ramps and jack stands I'm planning to drain all the fluids out and start fresh. I have a few bottles of Red Line gear oil. I need to find a decent speed shop here in Raleigh to buy supplies.

zilch321

Final confirmation on this whole drive line issue. Got my drive shaft from Mazdatrix today and got it installed. Vibration now gone and the drives smooth.

BTW, I installed some new exhaust hanger donuts - holy cow do those things suck to deal with when they are new. Those 500 dollar dyson vacuums dont hold a candle to the pure suck that is install those things...

BASTARD

iTrader: (4)

a little late as you already found out it was the drive shaft..

but for future readers... there should be no rotaional flex in the drive line... the best way to check it is to get a couple large channel locks... place one set on the same u-joint caps as the driveline and the other set on the yoke caps and twist them back and forth like the drive shaft would apply force... if there is any play your u-joints they need replacing... and since the u-joints are not replaceable in the 2nd gen you will need to buy a new driveshaft...

side note, your drive shaft could have been bent

zilch321

It might have been bent but I have been lucky to have a very clean car on the underbelly and there isnt any sign of damage to the shaft. Of course I have no other way to gauge this other than visual inspection.

In my case i'm 99% sure it was the Tranny side ujoint. It was frozen up bad in one set up directions (call it up and down), while the other direction (left to right) was fine. And by frozen I mean I put the shaft on my workbench and hit the damn yoke with a dead blow hammer and it still didnt move. Its probably been that way a long time.

James Norris

My drive shaft had no play in it either...But I still figured the U-joints had to be shot or the shaft was just un-ballanced because the car was so old. I bought a used one for 30 dollars in the for sell section and it fixed it. You could also do the mazdatrix drive shaft with replacable u-joints.

zilch321

Hey folks, I'm following up my thread with some more vibration issues. As you can tell from the existing posts I've replaced the drive shaft with a new one from Mazdatrix and I'm still getting a vibration in the vehicular. The vibration is now much less violent and more annoying than anything but I'm still trying to track down the source.

This evening I put the car up on jack stands ( a bunch plus the jack still in place), pointed the car away from the house and ran it up to 55mph standing still. I was still able to feel the vibration in the vehicle.

So where do I go from here? With a known good drive shaft installed and a known good balanced set of wheels? I'm taking the bushings in the control arms and suspension out of the pictures because the car technically wasnt rolling down the road. Am I stuck at this point replacing motor and or transmission mounts?