HAS ANYONE FIGURED THIS OUT?? I have the same issue for my 2008 G37 Coupe. The MM used to work a lot, and as time went on its worked less and less and now not at all. Any time I try to engage MM, it kicks me back into drive. DS works just fine, but only if I can get it to engage. Sometimes it doesnt engage at all. Brought it to Infiniti, they switched out the shifting assembly and that did not do anything, the same problem resurfaced. I AM GETTING MY CAR TUNED IN FEB AND WHAT TO FIX THIS BEFORE. Otherwise Im just gonna sell it. Ill get nickle and dimed to death with diagnostics

 

did you ever figure this out? The shifting assembly replacement didn't do anything for my 08' g37 coupe either

 

I had my transmission rebuilt and that didnt fix the issue either. I know all my switches in the shifter assembly work, so thats not the issue.

Ive heard a few people on here say that the manumatic sends a signal to the cluster before going to the ECU. A bad cluster might be the cause of manumatic not working. I might switch mine out one of these days just to try it out.

 

I contacted a few places about the gauge cluster and here’s what I found:
-Some local shops won’t do the cluster replacement since you need a certain tool to reprogram the mileage
-some people did this and it didn’t even fix the problem
-Infiniti charges $1700 for the cluster replacement and labor

I called a shop by the name of The Auto Service in Santa Ana. The guy I spoke new worked for Nissan/dotson for 40+ years. He knew a lot about the issue we are speaking about and is providing a fix on Monday, he says he’s is fairly certain he knows what the issue will be and can fix it. Just to remind you guys, I already did the shifting assembly replacement and that didn’t work either. I’m getting my car tuned in Feb at specialty Z, therefore I need my shifting!!!

 

Definitely update us if he does figure out whats wrong with it.

 

The signal is the dash cluster if you move the tilt column

in and out does it change ?

 

This little tip right here saved me hours of possible troubleshooting. I just got my instrument cluster board replaced and since reinstalling my Tiptronic (sport shift or whatever) would not work at all. I could put the shifter into that mode but it never when to manual. I adjusted my tilt column in and out, up and down, then my manual mode started working all the sudden. Crazy fix, but it worked for me. Thanks Dave!

 

Spoke too soon (karma). Sport shift is intermittent. Works every other drive. The saga continues. Ugh

 

Sounds like you need to clean the manumatic contacts on the shifter. Use a plastic safe electrical contact cleaner.

 

 

I have noticed my manumatic will always work for a few minutes on a cold morning. Then it will slowly start lagging the shifts and eventually quit completely.

I actually want to remove my gauge cluster completely and try the manumatic on a cold morning just to see if the cluster has any role in allowing the manumatic to work or not.

 

I think every other issue about the G35 has been figured out except for this damn manumatic issue. Nobody has been able to do it.

 

I drove around without my cluster installed a few weeks ago while I had it apart to fix something. The car would occasionally go into limp mode. I don’t recall if I tried manual mode or not. Let us know if you can drive no problem without the cluster installed. It had never gone into limp mode before or since so I’m confident disconnecting the cluster had something to do with it.

 

The only real change for me was the replacement of the cluster board. Since that my manumatic has worked intermittently. Have to assume it's something related but no clue where to go from here. Has always worked fine before the cluster board swap. I'll probably reseat the cluster connections and see if that helps.

 

I wonder if anyone is selling a cluster off of their car which had a fully functioning manumatic. We can get it and test it out on our cars to see if it makes a difference.