How stuck can I get with a bad drivetrain?

[tim eh?]

I've been getting vibrations from my drivetrain for a year now. Not a lot, just a tiny shake when the auto is shifting out of first. But recently it has been quite a bit worse.

I am due at the garage next week (for shocks/coils/mounts actually, after I do the tie-rods) but in the meantime I have around 12-1500 km to do this weekend, how is that for timing? Even if I am able to work on it myself I certainly don't have time before I go.

Just the last week it has been getting more noticeable. It happens between shifts 1,2 and 3 (shifting up only), and if I accelerate really hard (from 0) and turn a corner I actually get a (metal on metal) bang, it feels like something actually bumps the floor. I don't think it is the guibo thing, my mechanic noticed it before and he said he was pretty sure it was something else. I think U-joints are a common failure up here because of the conditions, it happened to my last car.

So anyway, can it fail catastrophically and/or wreck the rest of the car? or is it just going to annoy me more and more and force me to accelerate like a grandma? Can I lube it up for a one-shot trip?

no need for wisecracks about 'accelerating really hard' in an m20 please i know already :)

Thanks - I need to know soon...

[whiskychaser]

How stuck? Pretty permanently. If the prop lets go it could dig in and pole vault you into oncoming traffic.

[tim eh?]

How stuck? Pretty permanently. If the prop lets go it could dig in and pole vault you into oncoming traffic.

the prop is the centre mount thing? sounds nasty, I think I'll change my plans.

I am glad I asked because I was never any good at the pole vault - I either missed the mat or ate the pole.

[bubba966]

By prop he means the driveline. Lose a u joint at the front of the driveline and it's really nasty. Lose a u joint at the rear of the driveline and it's just nasty. I lost a center u joint in the driveline on my truck once. Luckily I wasn't going faster than 20 when it happened and the rear section of driveline wasn't long enough for it to dig into the pavement. But boy did it beat the **** out of everything underneath the truck.

Would hate to see what happens to an E34 that loses a u joint as it's got to be way worse than what I saw on my truck.

And it sounds like you're about ready to lose a u joint by what you described. Don't think I'd drive 1,500km if it really is your u joint on it's way out.

Get the rear wheels off the ground while leaving the tranny in park and try turning the driveline by hand to see if your u joints have slop in them. Might have to wiggle the driveline back and forth by the u joints to check them if attempting to turn them by hand doesn't work.

[Ross]

Even if it drops (which it won't) it ain't gonna' pole vault you. Urban myth, period. Take it from someone who has broken LOTS of driveshafts.
It sounds as if your center bearing support has failed. This will allow the center bearing to flail away inside the collar that usually has a rubber mount for the bearing. No real consequence other than it bumping around down there.
$20 and the pleasure of dropping your exhaust to change it.

[whiskychaser]

Even if it drops (which it won't) it ain't gonna' pole vault you. Urban myth, period. Take it from someone who has broken LOTS of driveshafts.
It sounds as if your center bearing support has failed. This will allow the center bearing to flail away inside the collar that usually has a rubber mount for the bearing. No real consequence other than it bumping around down there.
$20 and the pleasure of dropping your exhaust to change it.
I saw it happen to a 17 tonne council refuse truck. The back wheels only came about 3 feet off the ground. So if you need all 4 wheels off the ground to qualify for a genuine pole vault then this clearly doesnt:D. It only launched the truck onto the other side of the road. Acid test: ask your nearest and dearest what they think

[tim eh?]

Thankyou guys for the replies. I think she'd make it but I cancelled anyway. Gives me a chance to get underneath it this weekend and do the steering anyway. Will make for a much nicer trip with fewer shakes all-round.

I only have ramps and it's going in for shocks anyway so I will definitely inquire about getting this done then as well, I would be happy to not do it myself. I like working on the top, the sides and the inside:). I think Ross pegged it - that is exactly where the bump comes from, but I couldn't say. UJ failure I've experienced changed with speed, this feels like it changes with torque.