I have 2006 g35 coupe automatic transmission. At first the problem used to be when I would switch to manual it would still just read D but lately the problem is when I switch to Manual it will show what gear I’m in but now it won’t shift for example I’m in one I drive and when it’s time for me shift it won’t even though my car is pulling and rpms are telling me to. Or if I’m driving going like 45 I put it in manual and it’s in 4th I try to shift down and nothing happens sometimes or if it does drop to 3rd and my Rpms go up and it’s time for me to shift it won’t shift.
Does anyone know what the problem is? sounds like a transmission problem but I really hope not.

 

Most likely a problem with the micro switches in the shifter assembly. There was a thread recently about troubleshooting this kind of problem with pages from the fsm that will tell you where to probe with a meter to confirm your switches are operating properly when you switch to manual mode and then when you up or down shift. search for manual mode or micro switch and look for threads from a few months ago. if your transmission shifts normally in auto, you shouldn't have transmission problem.

While you're in there debugging do the thing to swap the up/down shift direction. There are threads about reversing that pattern too. Makes so much more sense to upshift by pulling on the shifter.

 

@jbarnett250 do you think buying a whole new shifter assembly would fix this problem?

 

maybe but i'd troubleshoot to confirm the problem first. i hate throwing parts at stuff without knowing for sure and spending money that doesn't fix a problem. testing the switches isn't very difficult. if you don't have a meter you can pick up a cheap one that will do the job for not much money and it will be useful for other work on your car.

i was surprised to see a shifter assembly on ebay for less than $50 https://www.ebay.com/i/273858518602?...oaAqMlEALw_wcB.

you can see the manual mode switches clearly in the photos on that auction. good luck.