Jason Guthrie

Problem/Symptom: When I accelerate over ~25mph, the car starts to shake violently. The shaking feels like it is coming from the cat or driveshaft area.

While driving and shaking, if I let in the clutch, the shaking lessens, but continues from inertia/momentum. Eventually the shaking will stop but by then, the car has usually coasted to under 10mph. If while shaking at +25mph I put the car in gear and let off the gas, a blink/second goes by (I think the driveshaft is waiting to catch tension from its connection points) and the shaking is immediately stopped/held.

I failed smog so I replace my 3 piece cat with a 1 piece bonez setup. This setup took care of any questions about the problem being the cat as it is smaller/lighter, has new hangers, and I got a good look at it when installed and it's not capable of the violent shaking in my opinion.

So, this leads me to believe it is the driveshaft. First, I have an 85gslse. Hayes manual says this driveshaft is not replaceable as it should never require it, then goes on to say how to replace it, then further specifies to take it to a shop such as mazda to have it machine calibrated to specifics no home mechanic could do. Further, Hayes talks about buying this new as it needs to have such precision adjustments, used would never do. Well a new one runs over $1000 ( I thought I saw) and that's bad considering the grand scheme of things.

The Questions:
1. Ever replace one of these?
2. Used parts ok, how specific do I NEED to get when installing?
3. Who might be able to help/do4$ me with this?
4. Anything else you think it could be?
5. Should I look or take it to someone to find out...who?
6. Hit the junkyard and pull this badboy out of a SE and swap it? =)

*I'm pretty sure it's my Hayes manual, I have like 3 fixit mauals and 2 speedshop manuals, I get them all mixed up.

Serzy

Go nab a used one out of a 1st gen. I dont even think the driveshaft is specific to the GSL-SE but look into that more first before you go pull one.

Also mazdatrix sells an aftermarket one that is only $242 and has replaceable joints.

Jason Guthrie

Thoughts on install price?
For my rx7 to drive smooth/er, I wouldn't think twice about dropping $250 on a new part. But install, is it gonna be tons or what. I'm headin to mazdatrix to see the part. I don't recall my manual saying anything specific about SE over GS/L, I just mentioned it in post incase someone knew already.

Does this mean I have to buy a new driveshaft or that the one they sell has driveshaft/u-joints that replace the ENTIRE unit? I must be tired as this really confused me.

clean

Hey Jason,
It's not all that much work to install it, I would say that if I had a hoist, I could take the old one off, and put the new one back on in 1/2 hour to 45 min. If you can jack the back end up, it actually comes off pretty easy, if you want to do it yourself. There's only four bolts (then you have to pound it off) then slide the shaft down a bit, and to the rear and it'll come off. You might find that you get some gear oil pouring out of the back of the tranny.. put a bucket there. Anyway, the new one should be easier to put on than it is to take off the old one.
If a shop does it for you, don't let them charge you for more than an hour tops (That's PLENTY of time)!!
I'm a real novice at this, and I found it pretty easy. Aside from having to find out that I needed to pound the back end off.. :p

Clean

Oh, and replace any oil that pours out of the tranny. That's easy to do too, just annoying 'cause there's not much room.

Jason Guthrie

Clean, you did yours yourself?
Did you have a similar symptom?
What made you think you needed to replace it?
How did it turn out and did the symptom go away?
What did yours cost total?
Did you replace the driveshaft or both the driveshaft and the ubolts?

The reason I ask is, a couple of sources say to replace the whole setup which includes the spider joints (each end where the driveshaft connects, ubolt area maybe?) but I believe that to have more than 4 bolts as you stated correct?

My car is way to low to get under. I doubt I could get it on ramps. I think I would have to take it somewhere. I'll have to call around for it.

Serzy

Replacing a driveshaft is a super EASY job just make sure you got a can of WD-40 and some metric wrenches and sockets a set of jackstands and a good jack and your set to go. To take out the driveshaft all you have to do is undoo the 4 bolts that hold it to the differential than wd-40 the hell outa that whole are and give it a few good whacks with a rubber mallet till it breaks free than just hold it and pull it out towards the rear of the car, and thats all!

Slide in the new one (there are some grooves on the output shaft of the tranny so it might be a bit tricky getting em to lineup but you cant put it in the wrong way so just rotate the shaft till it slides into the tranny than life it up to the diff and bolt in the 4 bolts and your set to go!

The driveshaft from mazdatrix includes everything youll need. I think it comes assembled and all you gotta do is the above process...



I had to do mine cause I swapped in a 5spd tranny and tosses the automatic tranny, and the driveshafts are different lengths.

clean

Hey Jason,
Serzy's right, it is super easy. I didn't actually replace mine, I was replacing the clutch so I had to take the shaft out, and put it back in. The hayne's manual goes through the whole process (it doesn't tell you to whack the driveshaft with a hammer to get it off.. but you WILL need to). Your car is too low, but you could buy a jack and jack stands (don't go under the car without jackstands) for about what it would cost you in labour to replace the shaft. Plus, if you enjoy that kind of thing, it's worth it!!! Then you have the jack and stands for the next time you want to play around under your car. :-)
Anyway, if you want to do it yourself, remember, if you have any problems, there's a lot of guys here who have taken out their driveshafts, so you'll have lots of help online!
Clean

Oh, and the hayes manual calls the driveshaft a propellor shaft. I bought my jack for about $25 CAN, (2 ton) and my stands were probably around $15 a piece (birthday present).

Pittdp

Mine started rumbling like my back wheels needed balancing, but when I took it up to the tire place he told me my u-joints were going out. I went to the local junk yard and found on that looked just like mine and bought it for 75 dollars. That was 7 years ago, and it is still going strong knock on wood. 83 Rx7.

Denny

Hey, Buckaroo...
My local Mazda dealer wants $400, for a new one...I'd most definitely go with MazdaTrix on this issue. That's unless you can score a quality used one from a yard. Do not! DO NOT! take the shaft to a shop like I did. Even when they say they balanced it, it will still have a slight vibration at certain speeds. Go new shaft, or quality used...

Denny, from the 'ol corncrib...

Jason Guthrie

How bout the symptom. Is what I am describing sounding like the propellar/drive shaft? LoL. I live in an apartment so this type of work is not allowed and my driveway is on a slope. I might be able to swing the work, however, I still wonder if that is what it is. Any other ideas on what makes the car shake like this?

Serzy

Most likely that is your problem, some vibrations can also be fealt if you have broken trannsmission or motor mounts... There are two motor mounts and one tranny mount, each are about $20 i think, the tranny mount is even easier to change than the driveshaft, not sure about the motor mounts tho.

Pele

iTrader: (28)

Get a garage in a box for like $50 from Track Auto or PepBoys. Hell, Even Wal*Mart sells em.

The ones at Track are made by G.M. GoodWrench or A.C. Delco (Smae people anyhow.) And are very high quality. They contain a pair of 3 ton JackStands, a good hydraulic floor jack, and a padded creeper. Good stuff. They had a big display of them at my local track... I may get one instead of laying on ground on a piece of cardboard and using cinderblocks to hold the car up.

CECCHIN

sounds similer to what happened to me. I was on the highway headding home at like 11pm and outta the blue my 7 sounded like she was goign to shake herself appart, i knew it was the drive shaft. so i rode in the break down lane @ like 5-10mph to my exit (luckly not too far) i got to the park'n ride and called my brother to come get me. The next day i went to have a look see and i jacked her up and got under her, and the rear u-joints lost its cap!!!! i guess the retainer clip came off somehow and loosened up, fell out. Lucky me my car is an 80, it has replaceable U-joint on the drive shaft. Heh, so i ordered the replacement u-joint and the day after i was up at the park and ride with my tools and jack, and took the drive shaft right off, at the park and ride mind you, it must have been a sight for peopel passing by, and i can't immagine what the peopel thought who saw me walk away from my 7 with the drive shft in hand, haha. I took it home and put the u-joint in and brought it back, put it in and later that day i had my mom take me back up and the 7 was good as new!!!!! I'd have to say it was the easiest thing i have ever had to fix on my car.

Jason Guthrie

Finally got the car smogged and back on the street so it's time to get this drive shaft fixed. But I got a few more questions:

If transmission fluids come out from the driveshaft area, how do I get them back in. I feel like an idiot but I thought there was oil, antifreeze, break/clutch fluid, and water. WHERE is this stuff coming out of and how do I get it back in from the bottom of the car? I guess I just don't understand this part. I was told my gearbox is sealed, meaning I don't fill it with any fluids...

Driveshaft from a GSL-SE at a junkyard, costly?, can I tell if it's still good?

And last, is there any way to tell visually or with my bare hands under the car if this is indeed the problem I should be tackling? For example, will the shaft slide forwards and back or wobble around. It kind of dawned on me that this could be related to a busted LSD or transmission from my "I think it makes logical sense" kind of way.

rockhead

Jack up the back or drive one side up onto the sidewalk. Use jack-stands, don't be a camaro driving bodybuilding idiot who drops his car on his head and bench presses it off.

Grab the dirty old drive shaft and try to spin it or wobble it and feel for any play. If you can wiggle it around with your bare hands its hooped and your hands are dirty! Brand new mazda shaft will fix it, of course its the same unserviceable piece of **** you've already got one of. I'd go for the mazdatrix unit, be sure they understand the exact car so you get shaft you want instead of getting shafted. I got a quote of four hundred cdn$ to convert my mazda shaft to replaceable joints and balance it by a local drive shaft shop. That price competes with the Mazdatrix unit so you might wanna shop around.

Once the shaft is out you should be able to move the joints easily and there should be no free play in them.

If you have no idea what age the oil is in the beast you might as well drain it and give it fresh oil, synthetic if you really love the car. you can drain it before the shaft comes out and refill it when you're done to minimize the amount you wear. The manual should have a handy entry point for getting the fluid in, sorry I don't know everything, yet, but I'm close ;-).

Felix Wankel

There is a drain plug on the bottom, and a fill plug on the side of the trans.