5th Gear Lockup on AT?
I have 2 Maximas that have topgear lockup once the tranmission warms up. I've looked in my owners manual for my '06 G35x and can't find any mention of this feature. The X's trans doesn't lockup in 5th. Is this the way it is or do I have a problem.
Also, in another thread the road speed vs. engine speed calculated to almost 27mph per 1k rpm, same as my '05 Max. My G35X is going 25mph per 1k rpm with stock 215/55-17's. Anyone see the same thing? |
I see the same MPH. ~80MPH i'm approx 3000-3100RPM on the tach.
As for 5th gear lockup, i'll check on my ride home today how it behaves. I beleive it locks up, but not completely. Not like a manual trans really. Even in tiptronic mode i don't beleive the converter is fully locked. I'll reply later after my commute home |
The JATCO 5AT can/will lock in 3rd, 4th, and 5th. If your tranny wasn't doing this, it would throw a code related to lock-up clutch/unit. The 5AT is very responsive, the gearing is deep, and the TC has a higher stall therefore the TC lockup isn't nearly as obvious. The lock-up mechanism is quick to release and is quite smooth.
As for the engine vs road speed, there are simply too many factors like overall tire height plus are you factoring in that the G35X has a deeper final drive than the standard RWD G automatic (3.3 vs 3.5)? |
3100 RPM at 80MPH on my '06X with stock 215/55's.
As for locking in 5th, it does. It's just not tight like a manual. If i stab the gas it blips up maybe 100RPM. If i let off, it drops maybe 100RPM. At lower speeds, it drops to idle though, as soon as i give it gas, it blips up to around 2000RPM or so and then locks up again |
Sorry to disagree with you DaveB. There are NOT too many variables. The internal trans ratio is known. The final drive ratio is known. The solling circumfrance of a known tire size is known. I think it was Mustang5L5 that posted an XL spread sheet that calculated the road speed in each gear and engine speed. I have it saved on the computer at work otherwise I'd post it again. If it wasn't you Mustang I can't remember who it was and I can't find it now.
I'm pretty sure that the engine speed drops to about 1k on the highway when I take my foot off the gas. I will double check and report back. In 5th 2.0Krpm= 50mph, 3.0rpm=75mph 3.2K=80 in my car. |
Originally Posted by Mustang5L5
(Post 4500626)
As for locking in 5th, it does. It's just not tight like a manual. If i stab the gas it blips up maybe 100RPM. If i let off, it drops maybe 100RPM.
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Originally Posted by Bassman
(Post 4500919)
Sorry to disagree with you DaveB. There are NOT too many variables. The internal trans ratio is known. The final drive ratio is known. The solling circumfrance of a known tire size is known. I think it was Mustang5L5 that posted an XL spread sheet that calculated the road speed in each gear and engine speed. I have it saved on the computer at work otherwise I'd post it again. If it wasn't you Mustang I can't remember who it was and I can't find it now.
I'm pretty sure that the engine speed drops to about 1k on the highway when I take my foot off the gas. I will double check and report back. |
At 80 MPH i'm right at 2875 RPMs. 2003 5AT.
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Originally Posted by Bassman
(Post 4500919)
Sorry to disagree with you DaveB. There are NOT too many variables. The internal trans ratio is known. The final drive ratio is known. The solling circumfrance of a known tire size is known. I think it was Mustang5L5 that posted an XL spread sheet that calculated the road speed in each gear and engine speed. I have it saved on the computer at work otherwise I'd post it again. If it wasn't you Mustang I can't remember who it was and I can't find it now.
No it wasn't me who posted it. Someone posted it for me when i was asking about final drive ratios for the X and RWD. |
Here's the table again with the values for an '06 X.
SPEED vs RPM CALCULATOR User entries here: (stock) Tire width (mm): 215 215 Aspect ratio (%): 55 55 Wheel diam (in): 17 17 Axle ratio: 3.538 3.538 5th gear ratio: 0.834 0.834 4th gear ratio: 1 1 3rd gear ratio: 1.471 1.471 2nd gear ratio: 2.264 2.264 1st gear ratio: 3.54 3.54 Results: Tire diameter (in): 26.3 26.3 Tire circum (in): 82.7 82.7 Tire revs/mile: 766.5 766.5 MPH/kRPM: 26.5 26.5 RPM: 5th 4th 3rd 2nd 1st 0 0.0 0.0 0.0 0.0 0.0 1000 26.5 22.1 15.0 9.8 6.2 2000 53.1 44.2 30.1 19.5 12.5 3000 79.6 66.4 45.1 29.3 18.7 4000 106.1 88.5 60.2 39.1 25.0 5000 132.6 110.6 75.2 48.9 31.2 6000 159.2 132.7 90.2 58.6 37.5 7000 185.7 154.9 105.3 68.4 43.7 Speedometer error if not corrected: (- means reads low) 0.0% I couldn't figure out how to post the actual spread sheet which allowed you to change tire size. |
Originally Posted by Mustang5L5
(Post 4502222)
No it wasn't me who posted it. Someone posted it for me when i was asking about final drive ratios for the X and RWD.
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Thanks for reposting the link Dan.
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