Hey guys,

Not sure if anyone else has experienced this, or something similar, but every so often I hear and feel a loud "thump" when the automatic transmission shifts from 2nd to 3rd. This only happens when driving in MANUAL & DS mode, under acceleration. Of course, the heavier the acceleration, the louder and more pronounced the shifting thump will be. IF I shift to 3rd while decelerating, or downshifting, there is no sound or knock coming from the transmission. is this relatively normal, or would it be a sign of a potential transmission problem later on?

At the same time, I also smell a synthetic burning scent coming from the underside, and this happens when I drive on DS, or ride on the same gear in MANUAL mode, for example, coasting on 4th, or even decelerating w/o downshifting. The smell doesn't bother me as much as the transmission sound, but is pronounced nonetheless.

My B2B warranty expires on the 3rd, I have also the Elite coverage, but I'd like to avoid any dealer pushback, and get the (any) issue resolved before they turn into something bigger.

Suggestions?

 

You're probably shifting too high or too low?

 

2>3 hard shift is common in the 5AT.

 

I am the original owner of a 2007 G35S 5AT. The hard 2/3 shift in manual mode is well-known. There is no TSB or known remedy. Other threads suggest it is not damaging to the car. I don't use manual mode much but definitely notice it when I do. I wouldn't worry about it....

 

^ There is a remedy but it requires a rebuild.

 

^ Thank you, I wasn't aware that it was all too common. As long as it's not damaging to the car then I'll be alright....

 

While 2nd to 3rd hardshift is common, there shouldn't be any thumping or feeling any "sounds" during the hard shift.

You might want to get that checked out under your warranty. Have you changed your transmission fluid recently? Usually, the hard shift goes away after a fluid change with OEM Matic S or Matic J. The transmission should shift smoothly after that.

My car has had a hard shift sometimes while in manual or DS mode, but never any thumping noise. I just feel a slight jerk when shifting hard, but that's only if I floor it and the needle goes to redline.

 

07 X, 55k miles and same thing, thud or jolt during hard acceleration in M mode when shifting 2 > 3... I already drained and fill transmission fluid with Matic S about 10k miles ago and it doesn't remedy the "problem". I use M mode sometimes so I hope I'm not doing damage.