94 540i - new owner - transmission & drivetrain

[S Fred]

I am the new owner of a 1994 540i. This is my first BMW.

From all I read about Bimmers, they are known for responsiveness and
silky-smooth transmissions. Mine seems neither terribly responsive nor
silky-smooth.

1) Shudder when accelerating. I know this can be related to driveshaft.
My mechanic confirms this, although it's not the "typical" remedies
that are recommended elsewhere in this newsgroup. Those fixes have
already been done. He recommends changing out the whole driveshaft.
Thoughts?

2) Tranny seems to not downshift as it should for first half-mile or so
of driving. RPMs very high, like it's not shifting into higher than
3rd. Then a noticeable "settling" of the transmission as it does what
it's supposed to do.

3) Generally, gear shifting does not seem smooth as silk at all.

I know this is hard to comment on in this kind of forum, but just
wondering what your thoughts are. I am aware of the Nikasil issue with
the cylinders, but not sure that any of these things have anything to
do with that.

Basically, it comes down to this: I bought the car to have a FUN car to
drive, right now it's not, and I don't know if it's my car in
particular or if my expectations are wrong/too high.

[Kalevera]

Most of this has been discussed in depth.

1) Drive shafts do go bad, it's a in the seat of the pants vibration. Shuddering can describe pretty much anything -- need more info.

2) It doesn't seem to be shifting past third when cold because it isn't. The transmission electronics are programmed to hold gears when cold to speed up the warming process. Once the car is hot, it shifts normally.

3) What's the mileage? Car could be getting ready for a valve body job.


It's probably the car. People typically sell used BMWs because they're a headache and they cost a lot to repair if you don't do your own work. If the car doesn't have much service history and is around ~ 130k, get ready for a cycle of replacing wear parts. After a while, it'll calm down and not require much maintenance.

[mattyb]

The 540 is a geat fkn car so your expections are right to be high. as kal said shuddering can be a number of things.
1. How are the tranny and engine mounts? first place to look
2. uni joint, how is it? CV ?
3. centre bearing and flex disc( guibo as some call it)? whats the story there
4. dog bones and rubbers etc
5. as kal asked whats the mileage???
6. Drive shaft change overs are expensive as they come as a complete unit, this is rarely an answer to anything.
7. have someone experienced in BMW trannys assess the tranny fluid and change or adjust accordingly.
8. we need to know more about the car to give any relevant help. eg: milage, history, condition, country located within etc etc. as there nuances from counrty to country with these cars.

ps. have you had a look under the car yourself and are you mechanically minded?

welcome and hope we can help and of course pics pics pics

[BillionPa]

if you let the car warm up from cold cold for exactly 180s, you will not experience the shift delays.

if you have the money, let a trans specialist drop the tranny, inspect the clutch packs and valve body, replace as necessary with new filter and fluid.

follow mattyb's list for diagnosis.

remember, your car is 13 years old, and if driven hard, that is a VERY long time. it will need maintenance in many if not all of its key mechanical and electrical systems to drive like it did 10 years ago, and depending on how much cash you throw at it, drive better than it did new.

[mattyb]

yes, good and very valid point about warming up there. it can never hurt to let it idle for a couple of minutes. btw fred nikasil would have nothing to do with issues you have at the moment. its only a valid point if u happen to live in some parts of the US with crap fuel local. The guys in the US will be able to help you there more than I cause Im in OZ and we never had nikasil issues here touch wood or laminate.

[markus]

replace enigne and tranny mounts. im sure they are in need of replacement if they havent EVER been. Mine were replaced at 124k and broke in 2 pieces on the way out. I had a shuddering under acceleration like yopu described and it pretty much cured it. Also I just replaced all 4 shocks and springs with bilsteins and eibachs and that got rid of a vibration under accel. Maybe wheel hop?

[Spasso]

As mentioned before, vibration in the seat of the pants could be slipping clutches in the transmission.

I test drove a 535 that only shuddered in first gear but totally smooth in the rest of the gears so that took the driveline out of the equation.

[jbourke]

... it can never hurt to let it idle for a couple of minutes

I'm sorry mate I have to disagree with you here ... the best thing for any car is to start it up and drive away gently ASAP. Oil pressure is not that great idling, especially when cold. And don't rev beyond 3K until oil has warmed up (depends on storage and outside temp).

[markus]

bmw even recomends driving as soon as you start

[BillionPa]

the amount of friction modifiers in your oil and its winter grade determine if letting the car idle is bad for it or not.

the primary reason bmw says to start and drive is to get the catalyic converters warm as fast as possible.