UH OH gear box concerns

[Lummox]

Evening all,

Had a scoot round various forums and haven't found an answer so i thought i would save the best one till last. I went out in the car this afternoon and i was approaching a T-junction where i was turning left. I slowed down and saw there was nothing coming so i went to accelerate and it seemed like the gearbox couldn't make its mind up as to what gear it wanted, I got a revving engine but no drive and then this almighty bang from the back end and acceleration like you wouldn't believe, it was so severe that i thought i had been rear ended "AGAIN". But no problems since, the only post i can find that comes anywhere near says that a guy fitted 22" wheels and it caused no end of bother - I fitted 22s about 5 weeks ago but had no dramas before this one time event. I have just phoned my friend and booked her in for a gearbox oil and filter change along with the transfer box and diff oils also on the change out list.
Has anyone else had the same issues???

Lummox

[X5Sport]

I had my E53 do this a couple of times when pulling away from Roundabouts, especially when not stopping.  For some reason the controls in the box seem to get into a tizzy and when it did sort itself out the drive engaged with, as you said, a god awful bang.  No idea what was going on but it was not a pleasant experience - definitely enough to make the engineer in me cringe. :'(.

It was as if part of the box said "we're going to stop" and then the ECU then said "go!" at the wrong moment.

It felt as if it could not decide between first, second or third and when it did decide the drive clutches just banged in with no overlap (the normal method).  500nm of torque being engaged suddenly is not pleasant! 

Richard

[Lummox]

Thanks for that Richard, I honestly thought someone had ran into the back of me. I checked the rear view mirror and there was nobody there then i looked at the girlfriend and got the "what the hell are you doing you lunatic" look. I tried to explain that it wasn't my fault but she was having none of it, after her being involved in 3 crashes last year and me in 2 of them (one my fault and one not) she is a tad nervous in a car now. I was just worried that it may be the early signs of a high dollar repair bill about to kick me between the legs haha

Craig

[X5Sport]

Understandable.  I looked in the rear view mirror to see if the transmission was still in the road behind me and in expensive shattered parts.....  :'(

Only did it twice, but.........

Richard

[Rusty]

I tend to shift into 'sports mode' when approaching any junction I think may either require a quick getaway or a rolling takeoff. This makes the box drop into 1st earlier.
As the X usually pulls away in 2nd, as you give it some the ECU declares defeat as the torque etc is all wrong and so stuffs it into first resulting in you earlier experience.

Not good for the car and makes you look like an arse in a 4x4 too.


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