Reverse Gear "slipping"

[Richard Ware]

Hi Guys, well i now have a 330ci Convertible, and all of a sudden when i put it in reverse gear the engine just revs up. It hasn't quite stopped working ie doesn't go at all, because on a level surface the car will slowly start rolling ever so slowly and if i feather the throttle a bit i can just about make it work.

Apart from asking the obvious question "what the bl***** he** has happened" is the gear selector somehow electric ie the selector lever does not directly connect to the gearbox.

Regards

Rich

[Guest Mr.Beemer]

hello Richard -

its an auto I assume '

does it lock in reverse & other gears?

get your gearbox oil/filter checked out :unsure:

[Guest DazH]

Like how dilly has pointed out, I assume it's an Auto tran..

Sounds to me as though you have a pressure/valve issue with the tran itself. When you take Dilly's advice (which is good advice), the transmission specialist you take it to will be able to quite easily diagnose this. Don't worry for now, just get it to a professional. Auto-transmissions are incredibly complicated so diagnostics without being there are difficult.

Please keep us in the loop!

Daz

[Richard Ware]

Yes its an Auto, The car works fine in all forward gears both in D and Tip Tronic mode. just to re-iterate, the car has SOME movement in reverse. it does not have "complete and permanent loss of movement to back up" which is the diagnose for the drum problem, some thing other sites have assumed. What is this pressure valve you talk about?

Also any idea on my last question re the gear selector.

With regard to taking it to a gearbox "professional" i assume these are the same ones i took my X5 to with a problem in D where it span up at 1000 revs and wouldn't change gear but worked perfectly in Tip tronic mode, Their advice "its knackered, need a replacement.. £2500" well i fixed it myself by jacking up the rear wheels and jacking it down, this cleared the problem and full functionality was restored.. problem was the rear air suspension compressor was broken and for some reason this affected the g/box, Don't ask me why. So my opinion of these professionals is somewhat jaded into thinking their opinions are financially biased

Regards

Rich

[Guest DazH]

Yes its an Auto, The car works fine in all forward gears both in D and Tip Tronic mode. just to re-iterate, the car has SOME movement in reverse. it does not have "complete and permanent loss of movement to back up" which is the diagnose for the drum problem, some thing other sites have assumed. What is this pressure valve you talk about?

Also any idea on my last question re the gear selector.

With regard to taking it to a gearbox "professional" i assume these are the same ones i took my X5 to with a problem in D where it span up at 1000 revs and wouldn't change gear but worked perfectly in Tip tronic mode, Their advice "its knackered, need a replacement.. £2500" well i fixed it myself by jacking up the rear wheels and jacking it down, this cleared the problem and full functionality was restored.. problem was the rear air suspension compressor was broken and for some reason this affected the g/box, Don't ask me why. So my opinion of these professionals is somewhat jaded into thinking their opinions are financially biased

Regards

Rich

Hmmm sorry to hear about that matey.

The problem with this situation is that, transmissions are sealed units and to take them apart you really (and I mean, REALLY REALLY) need to know what you are doing. I've known automotive engineers to base their entire PHD on auto-trans alone. They really are a mechanical nightmare if you don't know what you are doing. Like you said, their are cowboys out there so i tend to stay clear of railway-arch/industrial estate units next to a eastern european food companies. You'll want to try your best to find a really recognized specialist.

The cars I tend to own are older than your one so when a problem like this arises and a filter & flush does't solve it, it's far far farrr cheaper for me to just.... pop another tran in myself so.. I don't have much experience with this "Professionals" myself.

What you decide to do is up to you. Hopefully someone else will be able to input something a little more technical than me as a filter & flush is at the top end of my Auto-tran knowledge, sorry mate.

GOOD LUCK!! and keep us posted please

Daz

[Guest Mr.Beemer]

do you feel the reverse gear locks in such as the drive gear ? if not then there is a possibility of the gear selector.

do you here a certain noise in reverse gear like a low power steering fluid ?

I still strongly recommend you to check the level & condition of the gearbox oil at warm temperature after a short drive.

the gearbox units are generally built for life which don't break but what can wear out or fail is the torque converter which sits in the box itself. it all relies on the oil.

[Richard Ware]

Mr Beemer, HI. when i place the selector in R it selects exactly as it did before, if i'm on a flat surface that i wouldn't move on in N i start to move backwards, in fact getting faster up to 10mph if i let it, all without throttle. I dont hear the low power st fluid oil sound.

Would opening the fill bolt and seeing it oil drips out (like my X5) be the preferred way of checking level?

Thanks

[Guest Mr.Beemer]

I am assuming its not the gear selector problem as its locking in the way it should & it does move in reverse just slowly like turtle mode '

like DazH mentioned it could be a valve issue in the box where not enough fluid is getting to the reverse gear.

to check the fluid use the fill bolt when the car is on flat surface & warm after a drive. leave the car running select the park gear when doing this.

fluid should stream out through the plug. check the condition of oil, make sure its not fully black or burnt smell.

use the correct type of fluid if topping up is required.

repairing gearboxes & engines are two different things, its like a health doctor & a brain surgeon, same line but two different things!