A/T kicks into 3rd gear. Normal?
06-23-2006, 10:20 PM
#22
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Originally Posted by Suvlaki
What is "higher rpms"? It shouldn't upshift by itself but I have read that if you are redlining it (or close to relining) for a while, it will automatically shift up to prevent wear on the engine...
You might also be experiencing the VDC/TCS kicking in on curvy roads. The VDC/TCS system can override the driver if it senses an unintended steering input. It will happen on both the 5AT and 6MT. The system can employ part or all of the following systems; the VLSD, the Brake LSD, the throttle and in the case of the 5AT the transmission to correct understeer and oversteer. Try turning off VDC/TCS to see if it is the stability control intruding on the transmission. Also, try adjusting your driving style while in manual-mode. To get the best performance, while in manual-mode, you will need to adjust your throttle and shift points just like a regular MT. If you under/oversteer too much the stability control will kick in. I have an MY03 and my car only has TCS. I don't have the VDC to kick-in and correct under/oversteer for me and unless I loose traction I haven't had the tranny shift on me. Even in auto-mode the tranny will not shift on me in the corners if it senses a dangerous condition will result.
Last edited by Aggro_Al; 06-23-2006 at 10:50 PM.
06-24-2006, 04:43 AM
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No, the first thing I do is shut off TCS when I get in the car. I'm not hitting the rev limiter because, as stated in a previous post, it does it anywhere from 3-5.5k. I watched more closely yesterday when I was in traffic riding slowly in second gear. Whenever I reached the point the transmission normally shifted to 3rd it shifted on it's own, even though it was in sportshift. The gear indicator on the gauge cluster indicated the gear change. It doesn't do it every time though. If it did I would have already taken it in to Nissan but I'm sure I'll get a "unable to duplicate" and be charged a diagnostic fee.
Last edited by bmac03z; 06-24-2006 at 04:46 AM.
06-24-2006, 11:55 AM
#24
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Originally Posted by Aggro_Al
Your tranny should not shift up on it's own in while in manual-mode until you shift it. The tranny will not let you stall either, the tranny will downshift automatically if you drop below the stall speed and don't shift yourself.
The Nissan 5AT is a torque converter based performance tranny. The tranny is a real -time learning and adaptable transmission. The jolt you feel is mainly caused by two things and to a small degree the locked/coupled gear ratio difference between 2nd and 3rd gear.
The first thing that causes the jolt is the speed at which the 5AT shifts. If it detects that you are performance driving it will adapt it's shift speed to it's fastest setting and to the learned drivers style. This shift can happen faster than a blink of an eye. The Porsches do it in <200ms (yes, those are milliseconds) and the Nissan 5AT is very similar to that transmission which leads me to believe they will be in the same neighborhood. A human eyeblink is ~300ms for reference and a pro NASCAR driver can manually shift in ~0.7-0.8s.
The biggest reason for the jolt while in WOT is torque multiplication. You will get an instaneous boost in torque at the shift. The shift happens so fast that the tranny will have the ability to use more of it's torque multiplying ability. Torque multiplication is when the tranny outputs more torque to the driveshaft than the engine torque that is being input into the tranny. Many people think in error that a torque converter loses power. A torque converter actually has the ability to create more power to the driveshaft than what the engine alone is outputting. When the impeller (engine side) is spinning faster than the turbine (driveshaft side), like when you are at WOT and shifting, the stator will return excess fluid back to the impeller where the engine has an oppourtunity to re-accelerate the unused fluid to create more torque. The stock Z can almost double the engine torque some pro drag vehicles have 4x & 5x torque mulipliers. As, the fans get closer together in speed the stator gradually reduces the energy return to allow the fans to couple or lock.
The next thing that can cause a jolt is the the difference that the coupled 2nd gear ratio to the locked 3rd gear ratio makes. It's a pretty good size jump. But, because the 5AT uses a torque converter it has the ability to variably gear down to make that difference less then gradually return to the locked gear ratio.
On the 5AT, 1st, 2nd & 3rd have the ability to torque multiply. 4th gear and 5th gear are full lock-up gears. 4th and 5th gears use a mechanical clutch and don't use fluid coupling or fluid torque flow. You don't feel the jolt as much in 4th and 5th because they act just like the gears in a regular MT. They will not use fluid torque multiplication.
http://www.protorque.com/techi/ti_faq.htm#3
The Nissan 5AT is a torque converter based performance tranny. The tranny is a real -time learning and adaptable transmission. The jolt you feel is mainly caused by two things and to a small degree the locked/coupled gear ratio difference between 2nd and 3rd gear.
The first thing that causes the jolt is the speed at which the 5AT shifts. If it detects that you are performance driving it will adapt it's shift speed to it's fastest setting and to the learned drivers style. This shift can happen faster than a blink of an eye. The Porsches do it in <200ms (yes, those are milliseconds) and the Nissan 5AT is very similar to that transmission which leads me to believe they will be in the same neighborhood. A human eyeblink is ~300ms for reference and a pro NASCAR driver can manually shift in ~0.7-0.8s.
The biggest reason for the jolt while in WOT is torque multiplication. You will get an instaneous boost in torque at the shift. The shift happens so fast that the tranny will have the ability to use more of it's torque multiplying ability. Torque multiplication is when the tranny outputs more torque to the driveshaft than the engine torque that is being input into the tranny. Many people think in error that a torque converter loses power. A torque converter actually has the ability to create more power to the driveshaft than what the engine alone is outputting. When the impeller (engine side) is spinning faster than the turbine (driveshaft side), like when you are at WOT and shifting, the stator will return excess fluid back to the impeller where the engine has an oppourtunity to re-accelerate the unused fluid to create more torque. The stock Z can almost double the engine torque some pro drag vehicles have 4x & 5x torque mulipliers. As, the fans get closer together in speed the stator gradually reduces the energy return to allow the fans to couple or lock.
The next thing that can cause a jolt is the the difference that the coupled 2nd gear ratio to the locked 3rd gear ratio makes. It's a pretty good size jump. But, because the 5AT uses a torque converter it has the ability to variably gear down to make that difference less then gradually return to the locked gear ratio.
On the 5AT, 1st, 2nd & 3rd have the ability to torque multiply. 4th gear and 5th gear are full lock-up gears. 4th and 5th gears use a mechanical clutch and don't use fluid coupling or fluid torque flow. You don't feel the jolt as much in 4th and 5th because they act just like the gears in a regular MT. They will not use fluid torque multiplication.
http://www.protorque.com/techi/ti_faq.htm#3
I knew something locks up in the 2-3 shift. And no wonder why the 4-5 shift is soo seamless. If you look at the rpms in the 4-5 shift, it is soo smooth it just pops into gear. The 1-2-3 shift have a slight delay.
06-24-2006, 04:07 PM
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Just read the post by AGRO AL
Just wanted to say that my 04 5AT does the same but the real reason for this post is to say that AGRO AL's description of the cause of the "thump", as well as the general discussion of the torque converter and trans, is one of the best explanations of anything that I have seen on this site--good work and thanks for the info. I asked the dealer and all I got was a blank look. thanks again
06-24-2006, 04:57 PM
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Originally Posted by Aggro_Al
You might also be experiencing the VDC/TCS kicking in on curvy roads. The VDC/TCS system can override the driver if it senses an unintended steering input. It will happen on both the 5AT and 6MT. The system can employ part or all of the following systems; the VLSD, the Brake LSD, the throttle and in the case of the 5AT the transmission to correct understeer and oversteer. Try turning off VDC/TCS to see if it is the stability control intruding on the transmission. Also, try adjusting your driving style while in manual-mode. To get the best performance, while in manual-mode, you will need to adjust your throttle and shift points just like a regular MT. If you under/oversteer too much the stability control will kick in. I have an MY03 and my car only has TCS. I don't have the VDC to kick-in and correct under/oversteer for me and unless I loose traction I haven't had the tranny shift on me. Even in auto-mode the tranny will not shift on me in the corners if it senses a dangerous condition will result.
It seems stupid as there's no technical reason that automatic transmissions and stability control are mutually exclusive. There are plenty of automatic cards w/stability control so I'm guessing it might be marketing/market segmentation related.
Last edited by cwerdna; 06-24-2006 at 05:11 PM.
06-24-2006, 10:16 PM
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i have the same probles in my 03 g35 it seems to shift real rough inmaual mode almost like slipping in to gear. I recently changed my rims so he rears arent bigger than the front and it helped alot, but i have alot of experince with honda v6 tranny and they do the same thing and have hda a recall on them from 97 to 06, even if you buy A new one tomorrow there is a recall on the tranny. i think their is also one for the 350z and g35 from 03 to 04. Ill have tpo look back into it but Its either a recall or athey goodwill one if its shifts to hard. go ask the local dealer thats who told me when I had my 350z 6sp
06-25-2006, 08:34 PM
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Originally Posted by cwerdna
Uhh, you CANNOT GET VDC w/the 5AT. At least that was true with the 03 and 04 coupes and still seems to be true on 06 coupes. The best you can do is TCS w/the automatic.
It seems stupid as there's no technical reason that automatic transmissions and stability control are mutually exclusive. There are plenty of automatic cards w/stability control so I'm guessing it might be marketing/market segmentation related.
It seems stupid as there's no technical reason that automatic transmissions and stability control are mutually exclusive. There are plenty of automatic cards w/stability control so I'm guessing it might be marketing/market segmentation related.
Last edited by Aggro_Al; 06-25-2006 at 08:37 PM.
06-25-2006, 08:59 PM
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Originally Posted by Nismo 350z
I knew something locks up in the 2-3 shift. And no wonder why the 4-5 shift is soo seamless. If you look at the rpms in the 4-5 shift, it is soo smooth it just pops into gear. The 1-2-3 shift have a slight delay.
If you don't like the way the car shifts or want to increase performance you can try modding the valvebody, the torque converter and the ECU to adjust what you want.
As a matter of fact, adding a high-stall torque converter will give you the best bang for buck short of going FI. The mod is fairly cheap and you can go from a mild to extreme ranges depending on your preference. Depending on how high you raise the stall speed, you may be able to cut your 1/4 mile by 0.5 sec and still be NA and streetable.
Last edited by Aggro_Al; 06-25-2006 at 09:05 PM.
06-25-2006, 09:49 PM
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Originally Posted by Aggro_Al
I just built a fully loaded MY06 350Z 5AT and a fully loaded MY06 G35C 5AT on their websites. Both sites say that they come with VDC/TCS as standard equipment. On the 350Z side, some of the lower trims don't come with VDC or TCS regardless if it's an MT or AT.
During the 03-04 model year, there was no grand touring version. The only trims on which I remember you could get an automatic were enthusiast and touring and you couldn't get VDC w/automatics on those even if you wanted them. The highest end trim was track but that was manual only.
That said, the OP has an 06 touring w/5AT. You can only get VDC on that trim w/the manual.
06-25-2006, 09:51 PM
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Originally Posted by bmac03z
No, the first thing I do is shut off TCS when I get in the car. I'm not hitting the rev limiter because, as stated in a previous post, it does it anywhere from 3-5.5k. I watched more closely yesterday when I was in traffic riding slowly in second gear. Whenever I reached the point the transmission normally shifted to 3rd it shifted on it's own, even though it was in sportshift. The gear indicator on the gauge cluster indicated the gear change. It doesn't do it every time though. If it did I would have already taken it in to Nissan but I'm sure I'll get a "unable to duplicate" and be charged a diagnostic fee.
06-26-2006, 12:14 PM
#33
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Originally Posted by cwerdna
Uhh, you CANNOT GET VDC w/the 5AT. At least that was true with the 03 and 04 coupes and still seems to be true on 06 coupes. The best you can do is TCS w/the automatic.
It seems stupid as there's no technical reason that automatic transmissions and stability control are mutually exclusive. There are plenty of automatic cards w/stability control so I'm guessing it might be marketing/market segmentation related.
It seems stupid as there's no technical reason that automatic transmissions and stability control are mutually exclusive. There are plenty of automatic cards w/stability control so I'm guessing it might be marketing/market segmentation related.
06-28-2006, 10:18 AM
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How about 5th gear? if I'm in sport shift and shift to 5th, it will always downshift back to fourth within say 10 seconds. As soon as I put it back in full auto it upshifts to 5th though.
06-28-2006, 11:39 AM
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Originally Posted by bmac03z
How about 5th gear? if I'm in sport shift and shift to 5th, it will always downshift back to fourth within say 10 seconds. As soon as I put it back in full auto it upshifts to 5th though.
Take your car in for an inspection.
BTW How do you know what gear you're in when you're in auto-mode? The shift display will show what gear you are in when you're in manual-mode but it only shows a "D" when you are in auto-mode. Are you talking about the Z 5AT or another car?
06-28-2006, 12:11 PM
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Originally Posted by Aggro_Al
...BTW How do you know what gear you're in when you're in auto-mode?
06-28-2006, 02:04 PM
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Originally Posted by Aggro_Al
It shouldn't downshift into 4th from 5th in manual-mode unless your RPMs drop enough that it might stall.
Take your car in for an inspection.
BTW How do you know what gear you're in when you're in auto-mode? The shift display will show what gear you are in when you're in manual-mode but it only shows a "D" when you are in auto-mode. Are you talking about the Z 5AT or another car?
Take your car in for an inspection.
BTW How do you know what gear you're in when you're in auto-mode? The shift display will show what gear you are in when you're in manual-mode but it only shows a "D" when you are in auto-mode. Are you talking about the Z 5AT or another car?
07-25-2006, 04:52 PM
#38
Guys any update on this? Did a high stall TQ had any effect?
My AT sometimes shifts hard from 1 to 2, and especially from 2 to 3, after I depress the throttle following a kick-down. It feels like the shift is delayed and the car almoust slows down a bit, then the tranny catches up with the wheels again. Because of that the whole car shudders at a time - rather unpleasans I must say.
Before I ran into this thread, I though that I had a tranny defect, but now I am confused.
Minda
My AT sometimes shifts hard from 1 to 2, and especially from 2 to 3, after I depress the throttle following a kick-down. It feels like the shift is delayed and the car almoust slows down a bit, then the tranny catches up with the wheels again. Because of that the whole car shudders at a time - rather unpleasans I must say.
Before I ran into this thread, I though that I had a tranny defect, but now I am confused.
Minda
07-25-2006, 09:06 PM
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Does this ever happen to you guys, sometimes when I'm downshifting to a lower gear in Manual Mode, it will say that it shifted, but there's like a delay and the car will just no go for a sec and then start going.
07-26-2006, 09:10 PM
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You probably have one of the newer models that have the automatic downshift rev-matching. If you do, it's normal. That delay is the tranny rev-matching. Also, on the 5AT, if your downshift command will cause the tranny to overrev it will delay or cancel your shift to protect itself.