Like some others on here I have recently experienced a loud bang when pulling out of a side road and heading up hill. I had a quick check at the time and couldn't see anything obvious such a broken link arm or similar so continued my journey and everything appears to be normal. Today I finally got a chance to jack it up and have a look underneath, both drive shafts are fine with no play, there is no play in the diff flange or prop shaft joint and from what I could see there were no loose or broken items. What I did notice was that with both rear wheels in the air, the car in neutral (it's an automatic if that makes a difference) and the handbrake off, if I spin one wheel, the other doesn't turn which I would normally expect to see. Is this correct?

What happens if you drive slowly around full lock left, then, right. Do you get a build up of tension in the transmission - it will release with a bang.
Do you have 4-wheel drive when you accelerate hard from zero - if not front tyres will scrabble for grip. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 77k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

Hi Ian, no build up of tension in the transmission but not tried the flooring it from stationary to see if the front wheels have an issue getting grip, will give that a try and see what happens

Sorry I got interrupted before I added the link that includes info on Bell Engineering who are excellent at helping diagonsing transmission problems.
https://www.freel2.com/forum/topic33268.html?highlight=bang FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 77k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

dennij wrote:

Like some others on here I have recently experienced a loud bang when pulling out of a side road and heading up hill. I had a quick check at the time and couldn't see anything obvious such a broken link arm or similar so continued my journey and everything appears to be normal. Today I finally got a chance to jack it up and have a look underneath, both drive shafts are fine with no play, there is no play in the diff flange or prop shaft joint and from what I could see there were no loose or broken items. What I did notice was that with both rear wheels in the air, the car in neutral (it's an automatic if that makes a difference) and the handbrake off, if I spin one wheel, the other doesn't turn which I would normally expect to see. Is this correct?

The loud bang when pulling away and then seeming to drive normally can be a failure of the splined coupling between the gearbox and power transfer unit.
It happened on mine shortly after I bought it and the front offside wheel would often break traction when pulling away in damp or wet conditions. Following a chat with Austin at Bell Engineering I parted with some cash for a replacement PTU and coupling which I fitted on the drive (not easy) and that cured the problem and restored the drive to the rear wheels.

Same thing happened to my wife when she was pulling away and it turned out to be the front transfer unit spline and drive shaft unit had sheared off, £1426 later and the old girl is 100% again.

Thanks for all the replies it appears that as you have said my transfer box/PTU has given up. Not bad though as it managed 178,000 miles before letting go. Just trying to decide whether to repair or retire as I also have the dreaded tin worm on both rear sills.

What sort of money is it to get rusty sills fixed ? Watched on YouTube this morning a fella with a fl1. It failed the mot on a little hole, when he took the plastic off there was heaps of rotten rusty metal.