Wonder if anyone else is having this problem.

When downshifting my 2003 Sedan 5AT in manual mode, the transmission will jumb back up to a higher gear. For example, when I'm slowing down and shift from 3-2 or 2-1, the indicator and transmission instantly jumps back up to the higher gear (eg on a 3-2 downshift, it immediately goes back to 3). I'm not going to fast for the downshift so I wont be anywhere near redline in the lower gear. I've reset my ECU and it seems to lessen the problem for a short time, but comes back fairly fast. It doesn't seem to happen on the 5-4 or 4-3 downshift so I don't think the switch in the shifter is faulty. I suspect it's a S/W glitch. I've asked the dealer to check, but it keeps coming back NFF from the technician.

Anyone else heard of this and if so, is there a remedy

Thanks

2003 G35 sedan
5AT
Premium
Aero

 

I also have the 5AT. Never had a problem shifting like you
describe. But then I never downshift from 2 to 1 while moving.
I've had no problems shifting down from 5-4 or from 4-3.
It also sounds like you need to go to another dealer for service. They are not equally competent. I won't go back
to SouthWest Infiniti in Houston because of their lousey
parts department and arrogant service advisors.

2003 Twilight Blue 5AT Sedan, sunroof,
Graphite Leather, splashguards,
12 wire Hyper-grounding kit,
350Z intake duct, Stillen Hi-Flow Airbox
Underbody rear diffusers, Drilled aluminum pedals

 

Also a 5AT. Never experienced your issue. When I get a loaner, I normally practice my manul shifting skills and never experience what your describing unless you just don't shift and it red lines .

 

I have a 5AT.. the only time i have experianced the same issue is that if the revs are too high or the car is going too fast for the lower gear.. it will pop it back up.. :/

 

Yes, the transmission software doesn't like to let you bump it down if you're decelerating quickly. It plays it safe.

It helps to remember that it's more of a top-gear selector than a current-gear selector. The transmission will use all gears between 1 and whatever number appears on the dash as it feels necessary.

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter

 

i have a 5AT too but only downshift from 5-4, 4-3, and 3-2, never from 2-1 because you get this pretty big jolt most of the time if you do unless your mostly at a complete stop already. put the manumatic back into one only at a complete stop. the jolts from 3-2 . . . try to downshift when the rpms are anywhere from 1 to 2.5, at most three. it shouldn't switch back to the higher gear in that range

 

I have a 5AT too but I only shift 5-4 and maybe once in a while 4-3. For the most part I find the auto does a good job on it's own so there really isn't a need for me to get involved unless I'm looking for something to do. If you think you have a problem maybe take it to another dealer or take one of the techs for a ride and show him exactly what it does and when.

2003.5 Garnet Fire 5AT
Wishlist: Nismo CAI, Borla Exhaust

 

The only time I use it is on windy roads or when I'm turning left from a stop and want to get ahead of someone. You can keep it in the high torque band in 2nd and FLY.

G

2003.5 Black w/ Willow G35
Premium / Sport / Aero / Winter / Navi / Tint

 

Thanks for responding guys. It sounds like the transmission algorithm is set up to protect the engine from over revving. I downshift mainly to save the brakes (excessive wear) and to hold a gear when accelerating from an on-ramp. I guess if I really want to shift, I need to go get myself a 6MT.

Any news on the 2005....will there be any significant changes?

 

You shouldn't downshift to "save the brakes" anyway. Only downshift to maintain speed on a steep grade, or if your brakes have failed, or you're hauling a trailer. Clutch jobs for manuals and whatever you'd have to do to an auto after you tear it up costs considerably more than a brake job. Even without a 3yr/36kmi free brake/rotor replacement warranty.

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter

 

Yes Lee, I have a similar problem.....mine primarily jumps back up on the 4 to 3 shift that I frequently use when cornering. It NEVER did this until after my last ECU reflash at the dealership. I am driving the same as I was before the reprogram and like you, I am NOT downshifting with the rpm's too high. I hate it doing this and I am going to ask them to return my ECU program to the previous version on my next trip to the dealership.

 

I keep seeing things about ECU resets, is this something the dealer does routinely when you take it in for service, or what?


Brilliant Silver/Graphite '04 Sedan/5AT

 

What I am speaking of is done at the dealership...they upload the most current revision of the ECU software each time I go in - if a newer revision is available.

I have also read about(but not tried yet)people resetting the
ECU learning program by disconnecting the battery overnight. They say it makes a BIG difference in the 5A/T's performance.

 

Yeah, that's what I thought, but is that something they just automatically do when you have it in?


Brilliant Silver/Graphite '04 Sedan/5AT

 

The 5AT is controlled by the TCM (Transmission Control Module). The ECM (ECU) has very limited input into how the transmission "behaves". If my information is correct, there seems to be at least two if not more TCM programs.

Can someone confirm these are good part numbers for TCM software? # 31036-AL0000 & # 31036-AL0004


2003 G35 Sedan - DP / Willow / AT / Premium / Sport
350Z Engine Cover, T-Stat & Air Duct / Stillen CAI
GG 7-Wire H-G Kit / TechnoSquare ECU / E-Fans
Street Edge TC / B&M Cooler / Stillen Exhaust