Symptons of a bad Engine Mount and Tranny Mounts

[angusbn]

What are symptoms of a bad engine mounts - excessive vibrations constantly? Other?

What are symptoms are a bad automatic tranny mounts - ckunking noise when the tranny "shifts" between gears?

I'm still getting a ckunking sound around 10-20kmh when the tranny "shifts" into a higher gear.

Can't pinpoint the problem.

[dennyg]

I bought a 1989 535 a few years ago. Car had only 43K on it but I had to replace almost everything rubber on it. I was getting a vibration that I felt under the driver seat at idle. Changed the transmission and engine mounts. It solved the problem.

In my other E34 (94 530M) I was getting a similar vibration at 20-25 miles per hour then it would smooth out. That was a bad u joint and guibo and replacing them was the answer.

Your problem also could be just the sway bar links. 10-20 kms is slow enough where you could hear and feel a clunk but it would be up front and not drive train area. I even changed new ones and didn't tighten one enough and felt and heard a clunking sound going over a speed bump . You almost have to have a wall or building beside you to hear the noise bounce from it.

Hope I didn't confuse you more. I am not a good mechanic but all the above has happened to my cars.

[shogun]

Often, bad motor mounts allow the engine to rock and move around, causing noise and interference problems with the throttle, transmission and clutch linkages. For example, a thumping noise when the transmission is put into gear or when the vehicle is accelerating is a classic symptom of a bad mount.

Cracked or broken motor mounts can be an annoying source of vibration and noise, typically a clunk or shudder when accelerating hard.

Tranny mounts have similar symptoms.. It is generally a good idea to get these items replaced after 100k miles or so (or 8-10yrs) at the most.

Your engine won't fall out as a result of bad mounts, but the vibration can cause other problems as I alluded to.

I replaced my motor and trans mounts a few weeks ago, and the car feels much tighter, and is 'quieter' overall at idle and at speed.

If your mounts are even 50-60% worn you will find a noticeable difference in replacing them.

Yes, an engine shaking more than usual on startup is a classic sign of worn motor mounts.

If you change, change ALL at the same time, engine mounts, transmission mounts and the center bearing, because all are in the same line of the drive shaft.
Then you have a really smooth and quiet driveline.

Moving engine also can cause - in my opinion - the typical crack of the connectors at the radiator. Because the radiator is fixed onto the chassis and does not move, but the engine moves quite a lot when the mounts are not good, sometimes they are completely separated. Recently we changed the mounts on an E32 Alpina B12, the mounts were only 2/3 of the original size.

Such mounts should in my opinion be replaced anyway after a certain period.
At the same day we changed the engine mounts on another E32 B12 and an E31 B12, so 3 cars with same engine, about 4 years difference in production years and about almost 100 k miles difference in miles. All looked about the same. That tells me that not only driving makes the wear but just the weight of the engine over 8-10 years and the aging of rubber.

I am still not sure how much effect a bad final drive mount has. I never changed it on my car
http://bmwfans.info/parts/catalog/E34/Touring/Europe/525i-M50/LHD/A/1994/may/browse/rear_axle/differential_suspension/

[angusbn]

We'll the gargage called and they said they'd only replace the engine and tranny mounts on time taken to fix estimated as 8 hours or more. They had no shop rate for this job. Said the bolts were rusted badly but I suspect they weren't interested. I said don't bother I'd leave it for now. Red herring or legit excuse??

[Old Man Pete]

8 hours???? I did mine with ramps, axle stand and couple of jacks in about four hours, no pit or lift. That was for engine mounts, front and rear tranny mounts. Definately reduced a lot of vibration, now got to re-attack thrust arm bushes as I damaged them when replacing front struts and shocks :-(

[Mordan]

shogun. does changing all the rubber of the driveline means you have to remove engine and tranny?

[angusbn]

The mechanic sounded honest enough stating it was a big (expensive) job. He also said replacing the driveshaft center support required dropping the entire exhaust system from the engine manifold and he didn't sound gung-ho doing that either since the manifold bolts (studs) likely would require torching.

So the clunking sound will remain.

[BennyM]

To change the rubber mounts you have to support the engine and tranny some other way. You don't have to remove them. When I did mine, I used an engine hoist to hold the engine from above while I took the mounts out below. You could probably do it with just a jack stand or two. Fit the jacks snugly under the engine and tranny to keep them in place and replace one mount at a time.

BennyM


shogun. does changing all the rubber of the driveline means you have to remove engine and tranny?

[shogun]

engine mounts on my 750 takes some hours. But on a 535 it is faster, here some pics from a 735, see post 22
http://www.7-forum.com/forum/5/kein-tuv-109804.html
center bearing
http://www.bmwe34.net/Wiki/tiki-index.php?page=Center+bearing
engine mounts
http://www.bmwe34.net/Wiki/tiki-index.php?page=Engine+mounts

[Mordan]

thx shogun. I'm looking into.

but I agree the exhaust is a pain for the E34. at least mine with a M40. it is a shame.

while it is pretty easy to remove the exhaust on my E30 M20 no cata that's why probably. because you just have to remove the bolts of the middle muffler holding it to the pipes and remove the bolts for the rear muffler holding it to the car.

for the E34 M40.. hell you have to remove the bolts of the exhaust manifold. *******s, no intermediary pipes like on the M20.

[rockin1978TA]

I have a 89 535I thats is making a rattle/vibration between 10-25 mph. You can feel it in the front seats, and if you put your hand on the driveshaft tunnel behingd the console. Has anyone else replaced the center bearing/flex seal/transmission mount on a 535? According to the E34 site, you don't have to completley remove the exahaust, but he's working on a 525. Since I can't see what part has failed, should I go ahead and plan on buying a transmission mount/center bearing/flex seal?

[Ken35i]

I have a 89 535I thats is making a rattle/vibration between 10-25 mph. You can feel it in the front seats, and if you put your hand on the driveshaft tunnel behingd the console. Has anyone else replaced the center bearing/flex seal/transmission mount on a 535? According to the E34 site, you don't have to completley remove the exahaust, but he's working on a 525. Since I can't see what part has failed, should I go ahead and plan on buying a transmission mount/center bearing/flex seal?

I'm in the process of it now. You may as well replace everything. I took the exhaust out.
I had vibrations obviously in the driveshaft the centre bearing was the cuprit, well actually not the bearing itself it was the bearing housing; it had a couple of cracks in it causeing it to move.

[rockin1978TA]

So, did you have any problems getting the bolts out where the exhaust hooks into the manifolds? That's my only concern is breaking one of those. Also, any problems seperating the 2 drive shafts? According to the Bentley book , there is a sleeve that needs to be loosend, which says to use a specific BMW tool, then either a nut or a c-clip to get them apart.

[Ken35i]

Well, no. About a year ago now I replaced the head gasket and I bought new manifold-exhaust studs and nuts and I put anti-sieze paste on the threads. So this time around removing the exhaust was not as painfull.
When I removed the exhaust system to do the head job I did break one of those studs trying to undo it, as it was siezed. Apparently it was very difficult for the workshop to remove the little bit of stud that was stuck in the hole.

So if you can do the job without removing the exhaust, good.

The driveshaft in the Bentley is different to the one on my car.
RealOEM link. (http://www.realoem.com/bmw/showparts.do?model=HD12&mospid=47382&btnr=26_0042&hg=26&fg=10)
That's what my driveshaft looks like. There is no sleeve, you need to undo Bolt #9 to seperate the shafts and it's on f'ing tight. I'll post a picture of mine tonight, if I remember, as it's out of the car.

[Ken35i]

Few pictures.
Driveshaft:
http://img.photobucket.com/albums/v318/kenskee/DSC00141.jpg

Center bearing:
http://img.photobucket.com/albums/v318/kenskee/DSC00142.jpg

Center bearing again (this time you can clearly see the damage, was quite hard to see):
http://img.photobucket.com/albums/v318/kenskee/DSC00145.jpg

[rockin1978TA]

So you can get a wrench in there to remove that bolt, and seperate the two shafts? Looks pretty tight fit to get a box wrench in there. I have a feeling mine is a lot worse, by the amount of noise it's making.

[Ken35i]

I used a normal ring-spanner. I needed to put the shaft in a vice to undo it...very tight. You can undo the bolt say a few turns then 'pry' or 'push' the bolt forward which will hence push the shafts appart. Just remember to mark the shafts before you pull them appart... I didn't so I had to have them balanced my recent thread. (http://www.bimmernut.com/forum/showthread.php?t=41902)

[rockin1978TA]

I'm definately going to be doing this my self. My wife was getting impatient with me getting around to working on the car, so we took it to an independent shop we used a long time ago. He said he'd pull the driveshaft, exhaust for $308, which I thought wasn't bad, then he said parts would be another 400. i searched the parts on BMA's site, and came up about $106. I know there is mark up, but come on. I even gave him the list of parts from BMA with the prices. He wouldn't warranty any work if I bought the parts. He then commented on how the whole car was falling apart, I told him, my wife will be down in 30 minutes to pick it up.
This is after he first told me he didn't drive the car. Car runs and drives great, besides drveshaft chatter.