Driveshaft hitting transmission tunnel

[E28M5 SubDriver]

Have had this problem since I've owned the car - drive shaft seems to flex and hit the tranny tunnel on hard acceleration in 1st/2nd gears. I can feel the guibo clutch rub just for a second or two (kind of a thumping noise). My center support bearing broke completely last year and drive shaft constantly rubbed the tranny tunnel 'til I replaced the bearing. However, replacement of center support bearing did not correct the rubbing problem on hard acceleration. I am thinking my diff mount is bad:
http://www.bmwmobiletradition-online.co ... etradition
Part number 13 in the above link...I just replaced rear subframe bushings with no correction of the problem. I guess the other options are motor and tranny mounts, but I have no interest in continuing the easter egg hunt...Thanks for the help!

[Bimmerguy2002]

All those mounts are cheap and easy to replace, if the car is an M5 there should be no reason why they arent replaced.....
The diff mount is like 70 bucks new

Tranny mounts could be separated, id replace all the worn components all at once since they are a safety issue.

tranny mounts, guibo, center support, and diff mount should be in new condition.

[Kyle in NO]

You need to get another driveshaft. The U-joints in yours are likely binding up and causing your problems. Very common. No amount of new bushings or mounts will fix this. That is why there is an entire industry dedicated to reman driveshafts...

[Mark 88/M5 Houston]

I hate to say it, Matt is on the right track here. I'd replace the engine, transmission and differential mounts and then see where you are with the noise. I'd also check the rear face of the radiator, if the fins are damaged in a circular pattern your engine is flexing on the mounts enough to cause the fan to contact the radiator.

[igotbank]

You need to get another driveshaft. The U-joints in yours are likely binding up and causing your problems. Very common. No amount of new bushings or mounts will fix this. That is why there is an entire industry dedicated to reman driveshafts...

x2 I totally agree with kyle. I had the same problem a few years ago when i owned my first m5. I went ahead and replaced all of the mounts and the problem didn't go away. Had a tech friend test drive the car. After about a 2min test drive he concluded and suggested i get a driveshaft. I got a remanufactured one and never looked back. Good luck

[Blue Shadow]

If you do not want to replace stuff only to find that change did not fix the problem, you need to investigate the problem and replace the parts that will fix the problem. Subframe bushings...that ain't it.. You needed them so it is no big deal that they are new now.

Probably the same with all the other rubber parts mentioned in this thread, you need them so no big deal if you replace them.

But to solve your problem, you probably need to look at it carefully and see what parts are allowing the driveshaft to hit the tunnel. Motor mounts, tranny mounts and diff mounts don't seem to me to be the items that would allow the driveshaft to have such a deflection to cause the problem, but then I haven't had these parts in fully damaged condition on my car. So the first thing I would look at is the entire driveshaft, the guibo, the center u-joint, the csb and the rear u-joint. If all of that looks perfect then, and while the car is up, check the motor mounts, tranny mounts, diff mount and rear trailing arms (dog bones). You will find lots of stuff to replace.

Now where on the driveshaft is it hitting the tunnel? You should be able to see the marks if you experience this problem a lot.

I might have posted this in the Tech section so you could get the input of the community instead of just the guys that read and answer on the M5/M535i forum. Sure this system is M5 specific if it is the original type parts, but it is the same problem all E28s can have.

[E28M5 SubDriver]

Appreciate all the help. So far I've replaced guibo, CSB, rear subframe bushings, and Pitman arms. No evidence the radiator fan is hitting the radiator...As for the tranny mounts - do the UUC TME fit the E28 crossmember? These were a good product I installed on my E36 M3 and I seem to recall mention somewhere that they work on E28, but I am not 100% on that.

Anyone know where I can source the diff mount for $70? As I understand it, this part is M5-specific and it runs $245 at Maximilian. I know BavAuto carries reman driveshafts, but are they the best source out there?
-Josh

[Mark 88/M5 Houston]

You can use the M535i Diff Mount (331711297860) instead of the one specified for the M5. I would recommend either Beyre (sp) or Portland Driveshaft for a replacement driveshaft. I'm sure Steve Haygood can fix you up with any parts you may need. His contact information is here: http://www.mye28.com/viewtopic.php?t=21197

[skylere28]

You need to get another driveshaft. The U-joints in yours are likely binding up and causing your problems. Very common. No amount of new bushings or mounts will fix this. That is why there is an entire industry dedicated to reman driveshafts...

x2 I totally agree with kyle. I had the same problem a few years ago when i owned my first m5. I went ahead and replaced all of the mounts and the problem didn't go away. Had a tech friend test drive the car. After about a 2min test drive he concluded and suggested i get a driveshaft. I got a remanufactured one and never looked back. Good luck

DIDO to that ^

i got mine from bav and it was a good transaction i didnt have any complaints

[E28M5 SubDriver]

Great info - thanks all. Been lurking on the board for a while now searching old archived posts etc. to find answers, but finally pulled the trigger to tap into the collective expertise. I've owned E28 M5's now for 8 years and despite their quirks and problems I never get tired of them. They are just too unique.

[M5ZEALOT]

Hey, "brah" native Hawaiian here from Hilo. Nice M5 but man, you are in paradise, can't you post a better picture with some sand and coconut trees, hula girls????!!!!! There are lots of places on the North Shore or even by the Kalua Ranch perhaps. Missin' home.

check out my license plate frame.

[E28M5 SubDriver]

Hehe, what you don't like the photo in the parking lot in front of the AZ memorial on Ford Island with the Koolau's in the background? I have done a couple Kole Kole pass drives, but didn't get a pic. The car is filthy and about to get detailed this w/e. Will take it some place "nice" on Oahu for some photos afterwards. Not a local Hawaiian myself, but lived on Guam and HI for the past 5 years, so I am used to island life and caring for a rare BMW at the very end of the parts supply chain...

[M5ZEALOT]

Hehe, what you don't like the photo in the parking lot in front of the AZ memorial on Ford Island with the Koolau's in the background? I have done a couple Kole Kole pass drives, but didn't get a pic. The car is filthy and about to get detailed this w/e. Will take it some place "nice" on Oahu for some photos afterwards. Not a local Hawaiian myself, but lived on Guam and HI for the past 5 years, so I am used to island life and caring for a rare BMW at the very end of the parts supply chain...

I was just kidding....the parking lot with black top looks great! I lived on Guam too, my dad's last duty station was Andersen AFB. We lived in Yigo and Dededo. I hated the "cloud burst" where one side of the road was wet the the other dry.....so hard to keep a car clean on Guam. Maybe going to Oahu in Nov. to visit grandma, I should look you up.
THIS WOULD BE A NICE LOCATION FOR A PHOTOSHOOT - A WAVELESS DAY @ SUNSET BEACH!

THIS IS WHAT DRIVE IN OAHU, NANA'S CHEVY!

[Randomg]

So is the m535i part the same? I know the m5's was made stronger due to the extra engine power, so it would make sense for the m5 to have the stiffer mount.