Here’s the scenario. From a cold start, I drive at 30 - 40 MPH for about 1/2 mile to a RED traffic. As I gradually break, the light is long so there’s no hurry to get to it, the car downshifts normally in it’s cool G37x-downshifting-kind-of-way. BUT, when it shifts from 2nd to 1st, it SLAMS into 1st gear with a loud BANG that is somewhat unsettling. This event has happened to me three (3) times - once with my wife as a passenger. It has never happened to her while she was driving. Has anyone else had the same experience?
Well, have you checked the transmissions fluid level?
A 2009 - seems likely that it is still under warranty. A good transmission tech should get it on a scanner. If its under warranty, take it to the dealer. If not, find your best local, independent transmission shop.
How about a look at TSB’s? Transmission “events” usually makes their way there.
I spoke to Service at the dealer and he said he didn’t know anthing about the problem. I’m going to post on the Infiniti and G37 forums as well.
7-Speed ? A Nissan Technical Service Bulletin For 09 Infiniti FX35, G37, And M35 Models With 7 Speed A/T Only, Discusses Harsh Downshifts, But It’s A Harsh Fourth Gear To Third Gear Downshift.
For a harsh 4th to 3rd downshift, while coasting at 30 - 20 MPH with closed throttle, the Nissan bulletin written for Infiniti technicians, gives the procedure for reprogramming the TCM.
I don’t see anything for a 2nd to 1st problem.