Anyone solve the 3k Vibration? - Page 28

nightkrawler · 5th November 2009, 01:54

i would assume that the stiffer the mount is the more the vibration is going to be transferred. i think a solid aluminum mount would be much worse.

Vantaam, why dont you try this... get your car on the lift again, put a pole jack etc under the tranny, remove the top nuts off the mounts then jack the tranny up off the crossmember. then see if the vibration is still there, if its gone then we know definitely that this is how it is being transferred.

koolmofo · 5th November 2009, 18:26

Quote:

Originally Posted by nightkrawler

i would assume that the stiffer the mount is the more the vibration is going to be transferred. i think a solid aluminum mount would be much worse.

Vantaam, why dont you try this... get your car on the lift again, put a pole jack etc under the tranny, remove the top nuts off the mounts then jack the tranny up off the crossmember. then see if the vibration is still there, if its gone then we know definitely that this is how it is being transferred.

Hey nightkrawler, just wanted to add my experience. I recently had my clutch replaced, and since then, I have had the vibration
being discussed here. You can feel it more at higher speeds, and when it is colder outside. (just started to get chilly in the N-East) and I noticed it more this morning. I thought it was the clutch install, but perhaps it has something to do with the mounts. I haven't had a chance
to go back to my indy, but maybe the issue could be the wrong torque, or just bad mounts.

vantaam5 · 6th November 2009, 09:06

Will try tomorrow,nightcrawler and keep you updated!

nightkrawler · 7th November 2009, 23:10

well today i confirmed that the vibration is definitely being transmitted through the tranny crossmember. got the car up in the air and a jack under the transmission, then removed the crossmember. the vibration was totally 100% gone, not even a trace. i really dont understand how it is being transmitted through the rubber mounts, it dosent make any sense.

i also found out that bmw tranny mounts have a letter designation on them for how stiff they are. the factroy m5 mounts are type "N", which is pretty stiff. the lower the letter the softer the mount. ie A would be softer than B, and C would be stiffer than B. i tried a pair of e65 mounts which are type "M", made no difference. i have an old set of e36 mounts laying around which are type "K" which seem much softer than the stock ones. im going to give them a try but i doubt it is going to make any difference. im pretty stumped here, at this point idk how we're gonna fix this.

vantaam5 · 7th November 2009, 23:15

No idea yet on this

Thanks alot for confirming,nightcrawler!
Was today too busy to try it!

ANiMOSiTY · 9th November 2009, 08:22

Are the mounts maybe just a bit worn and thus softer than original spec?
Maybe a set of new N-type mounts will solve the vibrations?

escarolo · 9th November 2009, 12:16

What are exactly the "tranny crossmembers"?
Can you show them with pictures or a scheme?

Best Regards from Spain

vantaam5 · 9th November 2009, 14:17

I have brand new mounts and installed them correst and have it

nightkrawler · 10th November 2009, 00:28

yes mine are new as well and make no difference. the crossmember is a brace that bolts to the body and supports the tail end of the transmission via two rubber mounts.

nightkrawler · 23rd November 2009, 01:23

Vantaam5, i mine has gotten much worse over the last month. in fact ever since i lowered the exhaust to adjust the rear hangers the vibration seems twice as bad. when i first got the car i could never really feel it when i was driving, only in neutral. now i can feel it when the car is in motion as well. i also feel it now much more through the floor and the pedals. do me a favor please... lightly rest your foot on the clutch pedal and do the in neutral rpm run up test. see if you feel it in the pedals.

i think you may be correct in your theory that it is related to the headers. im wondering if one is cracked, maybe on the inside? i've noticed the following things since the vibration has gotten worse.

slight "exhaust leak" type noise from bank 1 manifold area
found fault code 140 in dme 1 time for 02 sensor control bank 1
vibration now felt more through pedals and floor, also shifter.
obc fuel consumption shows loss of 3-4mpg
vibration is much worse when the engine is fully up to temp.

what am i missing here?