B3 3.3 Gearbox issues - Help

[Rav]

A bit of an odd one. I have an e46 B3 3.3 (#032) which i use as my daily driver. Today, she let me down twice and I am worried.

Accelerating to get onto the M4 the car in the left lane of the slip road decided to cut straight across me. I let go of the throttle and the car acted very odd. All power was lost for a second, the dash lights lit up including handbrake, abs etc The radio also rest which is very odd, but the car did not restart or the engine did not have to crank over to restart at all.
I changed the battery a week or so ago, so thought little of this, convincing myself that it could be an earth strap.
Then as i got home, coming down the approach into Marlborough, i let go of the throttle and the car did the same again. Power is lost for a split second all dash lights come on and the radio goes back to the splash screen.

Is this gearbox a specific Alpina part or is it BMW? Does it use different software?

The car went to Birds last week for new brakes, diff oil and a few other bits. This could be a total coincidence. Today the car has acted up twice. They did find a code relating to EGS in the ECU and Kos mentioned clutches inside the gearbox starting to fail.

Any ideas please? Please help. Confidence in the car cannot be lost. She is my daily driver.

[Rav]

Ok, so i went out to investigate between meetings and rain showers.

It seemed odd that the gearbox issue would cause the power off/on of the car. This is more likely to be connected to the battery replacement of the car in the recent weeks. I assumed that this issue might be a loose battery terminal or earth strap.

I opened up the battery area to find....my smart new battery (replaced under warranty, thanks Eurocarparts). Both battery terminals were tight, but the gold coloured, round clamp was loose and moving about on the top of the battery, going up and downhill must have slid this thing into the battery terminals shorting +ve to ground. Hence the dip in power and the reset.

20240318_113326.jpg (3.67 MiB) Viewed 123 times

Gulp. It could have ended up nasty. Warning to others to check this. I have added some old spacers between the clamp and the battery now and ensured that it is tight. The original batteries must have been taller or sitting in a raised tray?

[hashluck]

Glad you found it. Have only just seen the post and reading the first one, no way did it seem like a gearbox issue but rather an electrical battery one even before I read the battery had been replaced. Under heavy braking explains what was happening in this case.

[JohnW]

Great that it was a simple fix, but could have caused a fire too. You have been lucky.

t’s a little like changing between winter and summer wheels, I go back to check the bolts with a torque wrench after a week and generally at least one has settled loose again.