Feeling very apprehensive about the potential problem in my transmission...

My 2007 Infiniti G35x sedan has this thud feeling when the car is downshifting from 2nd gear to 1st. All other gears are fine and are smooth when downshifting/upshifting.

In D mode, the car shifts fine at higher RPM's at gear, but when you let go of the gas pedal, you can feel a thud as the car is downshifting.

I also used manual mode, and the car has a hardshift from 2 to 1, while all other gears are fine.

I've had my transmission flushed about 3k miles ago by an Infiniti dealer in June of this year and filled it with Matic J fluid. Is this transmission thud normal? Should I be worrying about this? There's no check engine light or anything.

 

Hey Math,, all I can say is mine does NOT do such a thing, being we have the same car and all, smooth and silent all the way up and down, does not matter in DS, D, or manuel mode, however IF, mine did as yours I wouldn't be to pleased, and would be most concerned..... although I do not have 40,000 yet.... btw, matic J should be fine, its been superseded with matic-s now same stuff...

 

Yeah, my car is already at 80,700 miles, with mostly city driving. I think I'm just going to deal with it. Sometimes it doesn't do this while other times it does. The car isn't worth much anymore anyways and I'd probably trade it before the whole tranny fails.

Everything else feels fine though...so maybe my transmission is just getting old and slowly going bad.

 

My friend had a similar issue with his 2007 X. Got the entire thing drained and refilled and the problem ceased. His was around 140XXXkm's.

Might be worth trying out. I also have a 2007 X, without any problems. It now has 125XXXkm.

 

Could be a worn or broken transmission mount, or dirty fluid. How much did you guys pay for the transmission drain and refill or flush? Anyone using synthetic ATF?

 

I hope it isn't dirty transmission fluid, given that it was flushed 3000 miles ago. I paid only $200 for a complete flush at an Infiniti dealer in MA. They flushed it out with Matic J fluid, not Matic S.