5AT Manual mode - downshift miss?
Originally Posted by GixxerSteve
OP, if I remember correctly, I think the 03's (and maybe later years) do not have rev-matching like the 05-06. When you shift, the tranny will shift a little harder and the engine won't match the revs for the speed you are going, in the gear you are trying to shift into. Perhaps there is some safety feature that will not allow the transmission to downshift when the revs will be over redline in the lower gear??
Also, I don't know of any auto that will let you shift into a lower gear if the entry rpm is in the red.
A little OT, but does anyone else with an 03-04 5AT have the issue when you shift into manumatic mode, the LCD display shows "4" instead of the gear you are actually in? You can downshift, but it always starts out at "4". This is so irritating when you are at a stop, shift into manumatic, and it shows "4", so then you have to downshift to "1" so that it will drive like a normal manumatic as you accelerate. My FX is different (aka normal); when I am at a stop and shift into manumatic, it shows "1" because thats the gear I am in. It holds that gear as I accelerate until I upshift. And when I slow down to less than 5 mph, the gears automatically shift back down to "1". Plus it has rev-matching, so when I downshift the gears shift smoothly; there is no jerking like I'm popping a clutch on a stick.
ANY WAY TO FIX THIS/REPROGRAM THIS!?
ANY WAY TO FIX THIS/REPROGRAM THIS!?
Registered User
Joined: May 2005
Posts: 1,282
Likes: 8
From: Canada
Originally Posted by dTor
What exactly is a "rev-matching downshift"? 
Joined: Sep 2006
Posts: 125
Likes: 0
From: Calgary, Alberta, Canada
Originally Posted by DaveB
Update #2
I just got from lunch and drove around with the manual mode modification. WOW! I tried a 4 to 2 downshift at 50mph and it did it. No questions asked. I did a 3 to 1 downshift at 20mph and it did it. No questions asked. It's like a different tranny now.
I just got from lunch and drove around with the manual mode modification. WOW! I tried a 4 to 2 downshift at 50mph and it did it. No questions asked. I did a 3 to 1 downshift at 20mph and it did it. No questions asked. It's like a different tranny now.
Your the ****!
most, if not all 5at's start in 4th because it allows drivers on the freeway to switch over to MM mode. If your going at 60mph on the freeway, and switch to MM, and its in 1st, im pretty sure that would pwn your tranny. As for not being able to downshift , its because your revs would redline way too much. it requires atleast a below 6300 buffer in the lower gear in order for you to downshift.
for example, if your going at 70mph in 4th at 3500 rpm, u downshift to 3rd, it'll jump to 6000 rpm. *not exactly sure what rpm 70 at 3rd gear is .. taking a wild guess for example*
BUT if your going 80, and u jump to 3rd, your rpm range would be required to be atleast 7k? and since our cars can only go so high before the rev limiter starts bouncing and damage your tranny, so to fix that problem, Infiniti's ecu has a built in safety.
You can even test it yourself
Drive at a high speed in a high gear, then let off the gas and just keep pulling back on your shifter *not holding, but pulll back, let go, pull back, let go* until you actually shift down to the lower gear. Then the moment it shifts, floor it and you will notice you gunna bounce off the rev limiter right away.
for example, if your going at 70mph in 4th at 3500 rpm, u downshift to 3rd, it'll jump to 6000 rpm. *not exactly sure what rpm 70 at 3rd gear is .. taking a wild guess for example*
BUT if your going 80, and u jump to 3rd, your rpm range would be required to be atleast 7k? and since our cars can only go so high before the rev limiter starts bouncing and damage your tranny, so to fix that problem, Infiniti's ecu has a built in safety.
You can even test it yourself
Drive at a high speed in a high gear, then let off the gas and just keep pulling back on your shifter *not holding, but pulll back, let go, pull back, let go* until you actually shift down to the lower gear. Then the moment it shifts, floor it and you will notice you gunna bounce off the rev limiter right away.
Originally Posted by DaveB
Yes, the 03-04 cars do not have a rev-matching downshifts.
Also, I don't know of any auto that will let you shift into a lower gear if the entry rpm is in the red.
The 03/04 sedans automatically default to 4 when you kick the shifter over into manual mode. If you want a lower gear then you have to select it yourself. The 04.5+ sedans behave like your FX. There is no programming fix for it. I prefer the system because it works better at the track. I put the car in 2 and let it complete the 1-2 shift because it can execute the shift better than manual mode. Then I hold 2nd to 6300rpms and upshift to 3rd and hold 3rd the rest of the run.
Also, I don't know of any auto that will let you shift into a lower gear if the entry rpm is in the red.
The 03/04 sedans automatically default to 4 when you kick the shifter over into manual mode. If you want a lower gear then you have to select it yourself. The 04.5+ sedans behave like your FX. There is no programming fix for it. I prefer the system because it works better at the track. I put the car in 2 and let it complete the 1-2 shift because it can execute the shift better than manual mode. Then I hold 2nd to 6300rpms and upshift to 3rd and hold 3rd the rest of the run.
Dave, I thought the dealer had updated firmware that changed this behavior. I know my 04.5 coupe (with TCU embedded in the tranny, not in the passenger side footwell) does not exhibit this "top gear selector" behavior and I think it has the downshift rev matching as well.
Originally Posted by johnsonhuang
most, if not all 5at's start in 4th because it allows drivers on the freeway to switch over to MM mode. If your going at 60mph on the freeway, and switch to MM, and its in 1st, im pretty sure that would pwn your tranny.
BUT if your going 80, and u jump to 3rd, your rpm range would be required to be atleast 7k? and since our cars can only go so high before the rev limiter starts bouncing and damage your tranny, so to fix that problem, Infiniti's ecu has a built in safety.
Originally Posted by rcdash
Dave, I thought the dealer had updated firmware that changed this behavior. I know my 04.5 coupe (with TCU embedded in the tranny, not in the passenger side footwell) does not exhibit this "top gear selector" behavior and I think it has the downshift rev matching as well.
Originally Posted by GixxerSteve
Wow, this is good info. Is there any way to update the software in my 03 G's TCU to the software used in the 04.5+ G's (with the rev-matching and without the initial 4th gear selection)? Or if that isn't possible, could I simply replace the TCU from say an 05 or 06 G sedan into my 03??
Unfortunately not on both accounts.
Originally Posted by DaveB
The 04.5+ 5ATs will be in the appropiate gear if you select the manual mode while at speed. If you're going 50mph, it will put you into 4th.
3rd gear in the 2WD 5AT Gs is good to about 102mph. I've never had problem dropping the car manually into 3rd at 80mph.
3rd gear in the 2WD 5AT Gs is good to about 102mph. I've never had problem dropping the car manually into 3rd at 80mph.
Registered User
Joined: Jun 2007
Posts: 18
Likes: 0
my 03 must have an update, mine always seems to just shift straight over, from the gear it was in in drive, to manual in the same gear, except for gear 5, it always goes down to 4, which i dont mind too much because i am going to downshift anyways, i use manual for driving a little more.... agressively
Originally Posted by Nicb903
my 03 must have an update, mine always seems to just shift straight over, from the gear it was in in drive, to manual in the same gear, except for gear 5, it always goes down to 4, which i dont mind too much because i am going to downshift anyways, i use manual for driving a little more.... agressively
Okay, well after searching (oooh, the infamous "s" word) for TCM upgrades, I found many threads that basically answered my questions. DaveB was right, turns out many 03-04 owners have previously asked this question and there is no way to upgrade the TCM to the rev-matching 04.5+ model. However, I did find the instructions for the TCM Update here https://g35driver.com/forums/drivetrain/27842-sedan-5at-upgrade.html, so I will try to get my dealer to do this.
Originally Posted by GixxerSteve
However, I did find the instructions for the TCM Update here https://g35driver.com/forums/showthread.php?t=27842, so I will try to get my dealer to do this.
Originally Posted by DaveB
My 03 sedan has never grabbed 3rd if I want a double downshift like a 4 to 2. I don't know what it would do if I tried a 3 to 1, but I never manually grab 1st unless I'm at a stop or going anymore than 10mph.
UPDATE
A couple years ago I adjusted the metal pins that actuate the up/down shift buttons within the shifter unit. You can see the pins/buttons when you remove the console and look on the passenger side of the shift unit. I simply bent the pins so that they would engage the buttons quicker without as much shift lever motion. I had adjusted the upshift pin quite a bit, but not so much on the downshift pin. Last night I adjusted the downshift pin. Now upshift/downshift buttons engage with less a 1/4" movement of the lever. Today while driving, I was trying to get the tranny to second guess my downshift intentions (primarily a 4 to 2 downshift at 40-45mph) and it would plop into 2nd everytime This isn't the norm for my car at all. I don't how adjusting the pin made a difference, but it apparantly has. You might want to try it. Just be gentle bending the pin though.
UPDATE
A couple years ago I adjusted the metal pins that actuate the up/down shift buttons within the shifter unit. You can see the pins/buttons when you remove the console and look on the passenger side of the shift unit. I simply bent the pins so that they would engage the buttons quicker without as much shift lever motion. I had adjusted the upshift pin quite a bit, but not so much on the downshift pin. Last night I adjusted the downshift pin. Now upshift/downshift buttons engage with less a 1/4" movement of the lever. Today while driving, I was trying to get the tranny to second guess my downshift intentions (primarily a 4 to 2 downshift at 40-45mph) and it would plop into 2nd everytime
This isn't the norm for my car at all. I don't how adjusting the pin made a difference, but it apparantly has. You might want to try it. Just be gentle bending the pin though.will if bending the pins in the shifter helped than did you add a grounding unit too. my trans doesnt like to downshift into 1 some times. It'll to a pulse for a sec and than shift hard into first. People have told me that its not a smart to downshift into first unless you've got some type of upgrade
Thread
Thread Starter
Forum
Replies
Last Post
FRUG35
Engine, Drivetrain & Forced-Induction
1
Sep 11, 2015 03:07 PM
