Strange gearbox behaviour and weird noise from dash!

[ben wilamowski]

Hi all,

I have recently got myself a 1994 E34 540iV8 Auto, what an awesome car! Have always wanted one and now I want to get her absolutley spot on.

Couple of queries I would be really grateful for your help with:

1.The autobox is reluctant to change up when cold staying in what feels like second gear longer than it should. I am planning on changing the gearbox oil and filter plus transmission fluid and filter and the speed sensor in the gearbox and checking and cleaning any connections down there. Can you think of anything else I should do as a first port of call whilst I am working on the gearbox? Also I will make sure the connector from the throttle position switch to the gearbox ecu is a clean tight fit. Is it worth fitting a new throttle position switch? (Note the good news is that I am not getting any scary messages from the onboard computer!) I do not seem to have a dipstick for the box, is that right or am I looking in the wrong place?


2. I get a strange mosquito like whine on mild acceleration (not hard acceleration or gentle acceleration) this noise seems to be coming through the dash from the engine bay and is very strange, I am thinking it could be the belts or a problem related to what looks like a hydraulic fluid leak at the front left corner of the engine bay. This is kind of backed up by the steering feeling funny if you try to turn the wheel too quickly at parking speeds. I imagine I may need some new power steering pipes / reservoir etc and perhaps a pas pump.

3. Are there any gearbox oil cooler lines near the front of the car that could be leaking fluid?


Many thanks for your help.

Kind regards

Ben.

[Reidal]

Hi Ben, my 530 has the adaptive auto 5 speed with the A and S selector.

When cold, my tranny also holds a little longer than I would normally expect from an auto, but I think this is just a by product of the style of trans.

Mine also does lots of other neat stuff, like hold in a gear if you back off suddenly (like during hard cornering) and will down shift automatically as the road speed drops unlike most other autos that will coast to a stop before down shifting to low..

This is my first experiance with such a smart system, and it is the closest thing to a manual that I have ever had in an auto.

Others here may have a different slant on this but I beleive you may spend a lot of time and effort without any major change in what you see happening.

Ref the noise and fluid leak from the front left, I think that may be the power steering fluid as I have seen a number of V8's with seepage from around there and it always came back to the steering.

The noise maybe as a result of lower than optimum fluid levels, but I think there is a warning light for that.

Do you have the radio/stereo on? I get alternator noise coming back through an FM modulated CD stacker I have fitted, especally noticable when the headlights are on (system under load) and the CD is quiet between tracks. I'm planning a inductor fit to the power supply to try and cut this noise off at the pass.

The fuel pump on mine is on the Left hand firewall and it makes a noticable noise when the engine is not running but the ignition is on.

Does the noise go up and down with engine speed?

[ben wilamowski]

Hi Reid,

Thanks for the info on the transmission.

Ref the weird noise, I don't currently have a stereo in the car so it's not that.

I think it's mechanical and am just hoping it's not the box or the engine itself!

Cheers

Ben.

[ben wilamowski]

Still not really happy with the way the box behaves, it sometimes bangs in the changes quite harshly even when I am just driving along very slowly 20-30mph, it doesn't seem to change up and down smoothly. I used to have an E32 735i se auto and this was much smoother although it may have had a different box it had a 3 position switch sport, manual, economy. My 540 has the adaptive gearbox like yours with a 2 position switch Adaptive or sport.

Also if I am cruising at say 80 mph and I put the hammer down without engaging fulll on kickdown which drops 2 cogs it will just drop one cog but it bangs the change in rather like when you change a manual car and just side step the clutch without letting it out gently, just doesn't seem right to me.
Do you think this is just a characteristic of the box or do I need to worry about it!

[system11]

Also if I am cruising at say 80 mph and I put the hammer down without engaging fulll on kickdown which drops 2 cogs it will just drop one cog but it bangs the change in rather like when you change a manual car and just side step the clutch without letting it out gently, just doesn't seem right to me.
Do you think this is just a characteristic of the box or do I need to worry about it!

Mine does that too - I think the key point here is "put the hammer down". I may be wrong, but it _seems_ like the more you ask the car for above what it's doing, the more aggressively it will respond to the request. You'd expect that to be sports mode only, but that just holds gears longer and is even more likely to change down.

As a comparison, if I put my foot very quickly to the floor (but not kickdown) on mine, it gives you a swift kick in the back changing down, but if I use a progressive flooring rather than a stamp, it doesn't. Try it on yours?

[nixter]

Any update on your mosquito noise? Mine has this between 2600-3100 rpm. It's loudest when I let the engine decel through that rev range.

[EonPeon]

Years ago, an old BMW owner told me to NEVER drive (his 5 series when I loaned it) with the engine above 3000rpm until the engine has fully warmed.

I notice that my E34 530i seems to do this automatically, giving me crappy gear-change performance in favour of NOT letting the engine go above 3000rpm. Once warmed up, the gears changes work fine.

These cars have sophisticated computer-control. I guess that's what's happening here.

[pingu]

1. I think the autobox and engine work together when they are cold to hold on to the lower gears, thus helping the engine and autobox get up to their correct operating temperature more quickly.

2. I used to get a whine from my autobox on mild acceleration but only when the autobox was cold. Do a search on this forum for "5HP30" and/or "Filtrans" for details of the correct filter. The autobox doesn't have a dipstick - you should be able to find a link to the filling procedure. That's assuming the mosquito noise is the autobox and not something else.

3. Have you got a leak? (Your question isn't clear - at least not to me!) If so then try searching for power steering hose leak or something like that.