Nismo 350z

I dont get that and I have a full exhaust system done. BTW you shouldn't engine brake the car too much. The car automatically goes to 1st when you are coming to a stop. You should definatley get it checked out at the dealership. But yeah as others have said let the car warm up and drive for a while in "D" before switching to manual mode.

cvt

iTrader: (1)

hmmmm...this is becoming disturbing.

JoneZZZ

iTrader: (1)

I think folks are looking for a clear description of the problem.............

In manual mode coming from a stop in what gear?

how do you get an abrupt halt...before or after you stop with the brake? Is the abrupt halt from the tranny or your braking?


what is a "bum" noise?

Aggro_Al

I get the thud in traffic sometimes after I've shifted from 1st into 2nd but had to go back to crawling speed and the car shifts back into 1st. Normally, the tranny will not let you downshift to 1st unless you are going very slow. If I'm coming to a normal stop that isn't stop and go traffic I don't get the thud. My best guess is that it is caused when you are driving really slow in 2nd gear the tranny is torque multiplying so that you don't have to be in 1st. Eventually, if you are going very slow, your RPMs will drop to a level that 2nd can no longer maintain without stalling. Since, you were torque multiplying at that point, the turbine and impeller were spinning at different speeds to create the extra torque. Once the tranny shifts into 1st it instanaeously flashes straight to the stall speed and couples which is why you get that engine braking feeling and the thud when the tranny coupled (viscous locked). It's disconcerting but it it shouldn't be a problem as long as it isn't excessive or really loud. The higher the stall speed is set the more abrupt the gear change will be if you are torque multiplying when you shift gears. Get it checked out by a reputable mechanic if you think it's a problem.

cvt

iTrader: (1)

Aggro Al you always have the answers...thank you!

btw-how do you know so much about the tranny?

Aggro_Al

When I was first looking to buy a Z, I was originally going to get a 6MT. The salesperson got me to try the 5AT and mentioned that it was pretty advanced. I test drove the 5AT just to get the salesperson to give up on trying to sell it to me. In the end, I was really surprised and ended up buying the 5AT instead of the 6MT. I originally came from the school that said performance cars are always MTs and was curious as to just how much different the various transmissions were and learned about them from friends who are mechanics and from my own internet and book research. I eventually found out that I had a lot of misconceptions of ATs. I found out that performance of an AT or MT in a performance car is more a matter of design and preference and that both the AT and MT can be designed to perform in various ways. Driver skill also tends to determine how well a particular transmission works. I would go so far as to say that most drivers come up short on the skills side to fully utilize the potential of either type of transmission, myself included. I will say this though, the electronic controls of a well designed AT allow me to get more performance out of my vehicle than I could on my own and that in itself is fun to me.

rmesola

iTrader: (2)

not normal... mine shifts down to 1st when I stop... with no bump or anything...

I do get this strange sound when my car revs up to 2K rpm when I'm in 2nd or 3rd... disappears when i hit 3k rpm...

sorry for the hijack... just curious if anybody else has a similar experience..

UT Steve

No bump on down shifting. No grind in the mornings. I did the tranny fluid change at 30k.

CarlosZ

I've had it since new. I'm slowing down in 2nd gear(the car is wanting to slow down because it's in gear, I donwshift to 1st(the splitsecond hesitation puts the car into neutral causing the car to feel like it's not slowing down anymore,maybe speeding up or not scrubbing off speed because it's not in gear. Splitsecond later 2nd gear engages causing you to feel the sudden slowing down of the car into 1st. I don't think anything is wrong. I read that for 2005 and up the 350z had some rev matching feature my 2004 does not have.

Aggro_Al

Do you have a MY05 or MY06? In manual-mode, those models have automatic downshift rev-matching. Prior to MY05 the 5AT didn't rev-match the manual downshifts. The auto rev-matching made smoother downshifting but I don't think it added any performance benefits to the 5AT. If you want to rev-match automatically in a pre-MY05, just stick it back into auto-mode just before going back into 1st then shift it back to manual-mode once you've stopped.

cvt

iTrader: (1)

i tried her out and yes it is confirmed that the bump only happens when slowing form 2 to 1...but form 3 to 1 it's as smooth as a baby's butt...

ac8024

Sorry for the intrusion, but I have some noob questions about the MT mode on the 350z. I have a 04 350z, but I usually drive it AT everyday. Need help answering some of my questions. Thanks

Do I let go of the gas pedal then shift
or shift it as I gas?

How many rpm do you shift at normally?

Why does the 1st to 2nd gear feel more rough than others?

Can I downshift on downhill mountains
or leave it on the gear it is?

And can the 5AT do burnouts like a pure stick?

Thanks again

Santacruzslick

iTrader: (12)

Don't let off the gas.

Shift whenever you want to, I usually shift around 3k

1st to 2nd may feel rough if you're giving it hard throttle but shifting in lower rpm's, or if you let off the throttle at the same time as when you shift. Also, if the engine/tranny are cold the shifts may not be smooth. I usually go in full auto till it's warmed up.

You can downshift if you want to use engine braking, but it will automatically downshift when it needs to.

No, the torque converter will still keep you from doing a burnout like a stick would.

JoneZZZ

iTrader: (1)

Properly load the torque converter, and you can burn as much of your tires as you like............


Search on "stall speed" and "torque converter".....

nate_johnson17

iTrader: (14)

I've heard that before. I downshift through all the gears with no problem in my car, you might want to have that checked out.

ac8024

What would happen if I let go of the gas then shift? I used to always shift that way cause the MT tranny is like that. Will it damage my tranny or cause any downside effects? Thanks

Aggro_Al

It shouldn't damage your tranny. Usually you will get a lagged or sloppy shift if you lift off the throttle while upshifting. It's more noticeable in manual-mode than it is in auto-mode. On the manual downshifts, you might need ease off the throttle a little bit if you are going to go way over the rev-limiter or the computer will cancel or delay your shift until your RPMs drop. It's pretty hard to damage the 5AT because the computer will prevent you from stalling or excessively over-revving.

Minda

iTrader: (5)

I was searching for info on of AT thuds and ran into this thread.
After VB replacement, I am experiencing occasional thuds when in auto mode. So far I thought that the problem is overfilled tranny fluid, which prevents slippage for the "smooth" shifts.
Actually, it is very difficult to get that tranny fluid level right, as the measuring procedure in the service manual does not render any consistent results for me. Thus, I thought I would better run overfilled, rather than risk having too little fluid in the tranny.
Alternetive idea was a mismach of the ECM and TCM programs, but I think I would be experiencing much worse consequences.
Any similar experiences?
BTW, I had to replace VB, after it somehow got resetted while the car was shipped from USA to Europe (dead battery, etc.). Although after the batt replacement the car ran, the AT was not working properly - AT Check was constantly lit, kickdown and manual mode were defunct.

Minda