Driveline vibration....

[Mewsy]

525 auto M20, when i am travelling at around 70-80kph, the auto usually drops into 'lock out' like it is changing to a fifth gear. Lately, over time it has been shuddering into the lock out. Its not so bad if I am easy on the pedal, but under accelleration it feels like a slipping clutch on a manual. I topped up the tranny fluid the other day as it was a little low, nothing major but it made no difference. I have replaced the trans mounts about 15,000 k ago.
Since I have had the car - over 2 years, there has been some slight vibration in the driveline, my mechanic suggested the center bearing. Any thoughts on why this is happening now ?? Does my tranny have a flex disk that may need replacing, or is it something else. Any suggestions appreciated.:D

[genphreak]

525 auto M20, when i am travelling at around 70-80kph, the auto usually drops into 'lock out' like it is changing to a fifth gear. Lately, over time it has been shuddering into the lock out. Its not so bad if I am easy on the pedal, but under accelleration it feels like a slipping clutch on a manual. I topped up the tranny fluid the other day as it was a little low, nothing major but it made no difference. I have replaced the trans mounts about 15,000 k ago.
Since I have had the car - over 2 years, there has been some slight vibration in the driveline, my mechanic suggested the center bearing. Any thoughts on why this is happening now ?? Does my tranny have a flex disk that may need replacing, or is it something else. Any suggestions appreciated.:DI believe its just a centre bearing. Though the symptom could be caused by a broken bearing, it could also be shuddering from the trans as the lock-up torque converter engages.

Drop the pan on the tranny, change the filter (check the o-ring comes out ok and you get a replacement one with the filter). Also swap to Synthetic if you want to try to avoid doing trans rebuild, it's worth doing all these even if the centre bearing is the culprit. I'd expect the tranny to be the real cause. I had one do this once due to cruise control failiure (brakes+engine abusing the tranny) at high speed. It sorted itself out after the filter and fluid change and eventually went away.

BTW to check the centre bearing you have to pull the exhaust off, it is not that hard but you need the car up high, on a hoist is best. :) Nick

[Jon K]

It could also be the guibo - they work hand-in-hand the guibo and CSB. Replace both if you decide to do one, because you will be back in there all over again if you do not.

[HDhandyman]

I'll second what Jon just said. I had the same problem on the way back from Chicago the week before the meet. Lost my CSB (ripped), then lost the guibo (guibo=flex disk), then that shook the tranny mounts loose----It was nasty. Once you get vibe in any one of those parts, it's like dominos down there.

BTW, Jon K has some very nasty pics of what can happen with CSB and Flex disk somewhere around here....I looked, but couldn't find them for you, sorry.

[franan]

did you fixed your problem if yes e-mail me back why i have same problem from 40 miles to up i have a vibration but after 50 to up drive like nothing wrong.I just read your statement let me know what was the result.Thanks anyway.

[franan]

i have a 1990 535i auto with 89 k on it one owner recently i had a vibration issues i see a lot of people had the same trouble,but at 40 to up you can feel it after 55 drive with nothing .Also when i turn the main light on the car not moving no problem put the car on drive blow the fuse #5 front yellow light out dashboard and the rear left all at the same time can someone can help me.Thanks