Bad vibrations at certain RPMs...
 

When I take off hard I get a little vibration now at like 2 or 3k, and then at the end like from5-7 its pretty damn bad. If I take off normal & just go up to like 6, it does it when I switch gears. It feels like its up fron with the engine. Could it be the motor mounts? Maybe something to do with the flywheel maybe? It doesn't do it when its in neutral so you know. Any suggestions would help. Thanks.

O ya, its worst in 1st gear.

If it's really bad around 15-25 mph then my guess is bad front U-joint. I had that and it shook the whole dash pretty bad. Other possibilities include transmission mount. Haven't had that so don't know the symptoms.

Bad tranny mount, will vibrate in neutral while revving the motor. Push the clutch in and it stops. Well at least my 80 did...

Ok, it doesn't do it in neutral. It does it at like 2-4k in first gear real bad, then at 6-7k. In second gear it does it some too. Think it might be the U-joints. How would I check this & also how much would it be to fix? Can I do it myself? Thanks.

Not sure how to check exactly. But unless you already have an aftermarket driveshaft then the whole thing will have to be replaced. The stock ones had non-replaceable U's. Couple options though. There are a few people on the forum that have had their bad ones repaired by taking it to a machine shop or something. You can buy a new one, if so I would go ahead an spend a little extra on the one with replaceable U's (from Mazdatrix I think), or you can get a used one. I took a gamble and got one off Ebay. But it was only $15 so it wasn't a bad gamble, and turned out to be a good shaft anyway. Otherwise try junkyards.

So the part I need is a "U-joint"? What does it look like? Did you put your in yourself? Thanks alot.

Yeah, it sounds like the driveshaft (aka propeller shaft). You can't replace the u-joints, so you will need a new driveshaft. They are not really that cheap, so you may want to remove yours and check it out first, especially since it may not be the cause of the vibration. Oh, just remember to mark the bolts and washers before you remove them so that you can put them back correctly. What you are looking for is free movement of both joints - they tend to lock up on 2Gens, but any type of free-play "rattling" would also be bad.

You can get and aftermarket driveshaft from Mazdatrix. It won't last any longer than one from Mazda, but at least you can rebuild it. I guess that you could try to find one from a salvage yard, but I can almost guarantee that it will be worn, too.
http://www.mazdatrix.com/g4.htm

Well I looked at Mazdatrix & the aftermarket one is like $240 which isn't soo bad. I really have no clue how to change it but I guess if I got it I would see what to do, lol. How much trouble is it to change anyways? The vibrations aren't too bad really. First gear is the worst, second has a little from 2-3k or so, then nothing else. Car rides normal and everything besides the vibrating then. Hate to replace something that doesn't need replaced.

Easy as hell dude, just remove 4 bolts at the diff. and pull it off the spline in the trans. Reassembly is reversal of removal :)

If you ever have a front u joint come outta place, you'll change your tune. :) Get under the car with the e brake on and the tranny in gear and try pushing the drive shaft up and down, also try turning it , there should be little or no play in it. Especially up and down :)

Alright thanks man. I found a used one for $75, or I can buy a new one for $240. I think I might get the used one as I am on a budget right now.

Just remember that as soon as you pull the driveshaft outta the tranny, fluid is going to leak everywhere. And also, when you take the four bolts out of the differential, you have to spin the driveshaft around to get to all the bolts. So neutral is key in this situation.

How much fluid comes out? I don't want it all over my driveway. To tell the truth I don't even know exactly what to take apart. Anyone have any pics? Thanks alot.

if the vibratoin continues there are balancing washers on the 4 bolts to the drive shaft and diff. also check the tranny and diff mounts.

Alright, will check everything when I get off work, not sure exactly what I am looking for but think I will be able to tell if something is broken. Thanks.