[avantix]

Hey guys this is a weird one. Coming from a 320i and a 325i I have never heard this before. On my 335 in first or second gear under sudden acceleration I feel a sudden thump in the differential as if the second wheel is suddenly engaging? Anyone else experience this?

[srcstc]

Worn out diff bushings/mounts, *subframe damage* are my first guesses. Is it under warranty?

[avantix]

Originally Posted by srcstc

Worn out diff bushings/mounts, *subframe damage* are my first guesses. Is it under warranty?

Definately under warranty car is 2 months old but I think that the subframe prognosis may be a little severe no?. I have a feeling it might be some internal diff. component. It's almost as if the pseudo limited slip is engaging. Is it normal for the second wheel to engage if the car feels that the first will start spinning and should we feel this? Not sure how our stock diffs work.

Thanks

[srcstc]

Originally Posted by avantix

Definately under warranty car is 2 months old but I think that the subframe prognosis may be a little severe no?. I have a feeling it might be some internal diff. component. It's almost as if the pseudo limited slip is engaging. Is it normal for the second wheel to engage if the car feels that the first will start spinning and should we feel this? Not sure how our stock diffs work.

Thanks

Probably but who knows. There shouldn't be any thump at 2 months old. Is the car lowered or any other suspension mods?
If you have aftermarket rims put the stocks on before you take it in.

[budmanv24]

I've got something similar going on with mine right now. Waiting for the tow truck as we speak. Felt/heard a violent pop this morning. Thought I hit something on the road at first, and was like I didn't see anything. Looked back and sure enough, nothing. Pulled into my destination and it started popping violently as I was idling through the parking lot, jerking really bad too. So I limped back to work and now I wait. It does it really bad in 1st and reverse. Not quite as violent in the higher gears. I'm thinking it feels like the rear differential...possibly driveshaft u-joint but doesn't really feel like it.

[JayKay335i]

Originally Posted by avantix

Definately under warranty car is 2 months old but I think that the subframe prognosis may be a little severe no?. I have a feeling it might be some internal diff. component. It's almost as if the pseudo limited slip is engaging. Is it normal for the second wheel to engage if the car feels that the first will start spinning and should we feel this? Not sure how our stock diffs work.

Thanks

No. We dont have a limited slip differential.

[avantix]

Originally Posted by srcstc

Probably but who knows. There shouldn't be any thump at 2 months old. Is the car lowered or any other suspension mods?
If you have aftermarket rims put the stocks on before you take it in.

Car is completely stock. Gonna take it in. Maybe it's a u-joint or something.
Thanks for the advice guys.

[Dr.G]

Was it just a one time occurance??? Because its happened to me before in a 328i, what i think happened is i was in second turning in and ordered 1st throught the corner and gave it sudden gas at the same time.

It made a huge THUMP sound and the back axel hopped. otherwise the car can fine afterwards. IMO i think its a problem with the manumatics, it gets confused by the 2 conflicting orders at the same time. Change down gear and Power at the same time. Try giving it a little time to complete the gear shift b4 putting down the hammer. If it still happens then by all means take it to get checked out.

I might be completely wrong because this has only happened to me once but the description you gave reminded me of that incident

[Perfectus]

If the car is that new, I'd take it into the dealer immediately to get it checked out. Maybe someone forgot to tighten a bolt somewhere down there!