Alright gurus Im gonna need your guys help. I just replaced my front diff mounts today.

The car is still having the same problems as I had before. It still clunks everytime I hit the gas. Above 55mph I get alot of vibration. And if I slow down in neutral from 65 it gets a even bigger vibration. But if I just let of the gas in gear from 65 down there is no big vibration.

So what do I do now. All I can think of is to replace the driveshaft.

 

Heres a pic of the old mount

 

theres something seriously wrong with that picture..
I cant put my finger on it...
its like... that mount... its.. not broken!

 

trans mount? crossmember? if its not the diff mounts i dunno

 

Driveshaft.

And that diff mount looks like the competition mount, which is know to be trouble-free in most cases.

Driveshaft balance or bad u-joints would also explain the vibrations.

Actually I take that back, it looks like it might be the stock mount with the weight block removed...

 

sounds like bad u joints

 

is it possible for a driveshaft to just randomly become unbalanced?? i pulled out of costco the other day and all of a sudden i had a mean driveshaft vib and its still doing it, the u-joints feel fine on mine.

 

I've already replaced the Transmission mounts and the cross member. Yes that is the stock mount with the weight block removed. The shop but the weight block onto the competition mount.

I am now planning to get the Mazdatrix aftermarket driveshaft and ujoints now. Is there any general info I should I know about it.

Do you think I should be warry of the Rear diff mounts?

 

Probably the driveshaft but another thing that will cause a clunk, if if the camber link has a loose bolt at the bottom.

I don't recall the real name of this LINK, but MAZDATRIX sells one and calls it an adjustable camber link. It's about a foot long and is installed in a up/down position. See the Mazdatrix site for what I talk about.

The reason I know about that one is because I removed the Mazdatrix adjustable one and reinstalled the original one and did not fully tighten the lower bolt. CLUNK upon starting off from a stop.

Third picture from the bottom at this: http://www.mazdatrix.com/h6_86-92.htm

 

The clunk is mainly coming from the shifter area and little bit behind me in the middle. I'll make sure to tighten up all the bolts when I do the driveshaft.

 

Should I be worried about the rear diff mounts at all . I bought the mazdacomp ones but are about to sell them because I hear that the rear diff mounts almost never break or have any problems.

 

they don't break often from what i hear but they probably are worn out though.

Definately sounds like a u-joint problem though.

 

but even if they are worn they would not cause this clunking noise?

So yea definitely will be replacing drive shaft and u joint in the near future.

 

what kind of 7 do you have cause i have a mazda trix drive shaft with around 10k miles on it for any n/a's if your intrested. i would want 100 plus shipping thanks.
let me know

 

+1 on u-joints.

and you wasted $180 on a new diff mount, that one is perfectly fine, you can mail it to me though.

 

damnit... oh well lets say I fixed a problem that would of possibly happened in the future. Lets look at things on the positive side and that diff mount was only 100 bucks it was the mazda comp one. And if you would like the mount its up for sale on the west coast section give me a price.

and on the driveshaft mines is N/A. But I would rather get a new one. not saying that yours would be fualty or anything but I just want to make sure this problem gets fixed.

 

thats cool, ill just put it on my car

 

yeah that diff mount would bust eventually. Pull the driveshaft and check for play in the u joints.

 

If it's not the driveshaft what else could it possibly be? I've already checked the diff mounts they are fine I have the mazdacomp front one now. Is there another thing that could cause this problem?

 

my vote is for excess backlash in either the diff or the trans. NA trannys are junk, so its a good possibility. if the rear hasnt ever been opened then it probably also has loose clearances.

 

backlash wouldn't cause a vibration, only something out of balance would. so for balance you have accessories at the front of the engine(rarely cause a balance issue), the engines internal/external balancers and they would only be of issue if the flywheel key somehow got sheared off and spun the flywheel 180* out or if the engine was improperly built with the wrong parts(this would not come out of the blue one day though, only come about after an engine install), the driveshaft, half shafts and the wheels.

wheels rarely cause a balance issue to come and go, it may vary with speed but it is consistent with speed, not load.

a driveshaft can vary in balance if the u-joints are worn, hence why with load it may either get better or worse and with no load it may vary as well.

engine/accessory imbalance is RPM dependent, not speed or load dependent.

all that in mind you see why i chose the driveshaft as the likely culprit. something else to think about is: some vibrations are normal and transmitted through the body through worn mounts or broken mounts so inspect all the suspension bushings, engine/tranny mounts and rear diff mounts if the u-joints feel tight.