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/E3...al_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-inde...Center+bearing
engine mounts
http://www.bmwe34.net/Wiki/tiki-inde...=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.