Transmission Thump On 4.8iS – 1st To 2nd, 2nd To 3rd

[Ricko]

Just wondering if any forum member had experienced anything like this…..

I’ve recently become aware of a noise which can only be described as a bit of a thump when going from first gear to second gear or second gear to third gear. It normally happens when everything is warmed up but it’s not noticeable in the higher gears or under hard acceleration through the gears.

My initial thought was suspension bushes but as the car as just passed its MOT then maybe not. There has been no transmission or self levelling suspension error messages either.

I searched Outpost and a couple of people have experienced something similar. On the 4.8iS as well…..Feedback from other users points towards transmission mounts, the transfer case on its way out, wheel bearings or a chain in the transfer case. As I have a relatively low mileage car I would hope that’s its none of these………

Anyway the car is booked in to my local BMW dealer next week so hopefully anything they find can be carried out under the warranty that I have recently extended.

[CondorX5]

Rick, just keep moaning on about it to the dealer if not totally rectified, if the whole transmission has to be replaced so be it. Love the warranty! The cases I've read seem to end up with gearboxes being replaced in some cases. Not a bad thing to try to have the entire 4.8 rebuilt during the warranty - I think Turks has just about managed that now I need to roar around a lot more in mine - my first year is coming up end July, but I'll renew the warranty, its kind of silly not to, with the 4.8. I'll use the MOT Guarantee next month though.

[Turks]

I think the gearbox is about the only thing that I haven't needed to have done on the Warranty!

Although it has just passed its MOT, the rear subframe bushes can be overlooked - it just depends how thorough your MOT tester has been on his visual checks. Rear subframe bushes would give this sort of symptom when changing gear.


Turks.

[Ricko]

Thanks for the tip. I'm going to have a good look under the car today at all the suspension bushes to see if there is anything obvious........

If it is sub frame bushes I don't think I'll be able to claim anything throuhg the warranty as the dealer will proabably claim wear and tear. I'll check the small print just in case.

[Ricko]

Well I had a good crawl about under the car to have a look at all the suspension bushes……..There’s some play in both the front sway arms.

The rear sub frame bushes look OK although I’m not sure how you would determine if these were on their way out. No signs of cracking or perishing.

Oh well……..Can’t do any more……Lets see what the dealer finds……….

[Ricko]

Update on the thump............

Took the car in today to my local dealer..........The service administrator suggested taking the car out for quick drive with their technican so he could listen for the thump.

The technician heard the thump so I left it with them.........

Got a phone call this afternoon - They are going to replace a "propshaft bearing" so they are keeping the car overnight. This will all be done under the extended warranty so only £100 excess to pay.

I'll ask for a pro forma invoice for my records so I can post the part numbers for reference. Might help someone else in the future. I just hope this sorts the problem out.

[Turks]

Glad to hear it Ricko. Warranty is great eh?!


Turks.

[ANDROID]

The problem may be in the sliding clutch, try to look at it. or it could have a leak in the repair kit. It's either in the master or secondary repair kit. Hope this helps!