Drivetrain Questions and info regarding transmissions, clutches, etc.

RPM's at 80 MPH

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Old Dec 17, 2009 | 11:21 AM
  #76  
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Originally Posted by DaveB
If you want CC at speeds at over ~73mph, then don't swap in the 3.5 gears. Do a quick search and you'll dig up numerous cases of 03/04 cars loosing CC above 73mph when going with the 3.5 gears or lower. The 04.5 cars might not have a problem, but the 03/04 cars do.
Thanks Dave.
I've read some of that before, but I didn't realize it was only affected over 73(ish)
So I'm guessing this is caused by the ECM (or TCM or someotherCM) seeing a different ratio of the VSS in the tailshaft vs the ABS wheel speed sensor? If that is the case, I can setup a microcontroller to multiply the pulses coming from the VSS by the ratio of the differance between a 3.3 and 3.5 and that should fix it yes? Or I'm I all the way in left field again?
 
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Old Dec 17, 2009 | 01:34 PM
  #77  
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Originally Posted by nfsp1
Thanks Dave.
I've read some of that before, but I didn't realize it was only affected over 73(ish)
So I'm guessing this is caused by the ECM (or TCM or someotherCM) seeing a different ratio of the VSS in the tailshaft vs the ABS wheel speed sensor? If that is the case, I can setup a microcontroller to multiply the pulses coming from the VSS by the ratio of the differance between a 3.3 and 3.5 and that should fix it yes? Or I'm I all the way in left field again?
Yes, I believe your right. The TCM/ECM sees a discrepency and the 73mph speed must be the point at which discrepency is large enough to either flake out or shut the system down. I also think you're on to something with regards to making something fool the ECM. I think the fix should be quite easy. I'm just not an EE nor bright enough to figure it out. If you could fix the system so that it stayed engaged until at least 79mph, it would great. I'm sure you could sell it.
 
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Old Dec 17, 2009 | 02:20 PM
  #78  
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^Yeah, 79 is the magic number LOL!

I don't think it will be too hard. I built a digital speedometer for my Trans-Am, so I'm used to dealing with a VSS. Only trick will be generating the 'fake' signal in a way that the ECM/TCM will still read it. I don't know anyone locally that has a swapped diff so I guess it'll just have to wait until I do mine.
 
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Old Dec 17, 2009 | 06:54 PM
  #79  
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Originally Posted by nfsp1
^ So you went from a 3.3 to a 3.7 right? And your speedometer is still right and your cruise still works?
I'm thinking about going to the 3.5 LSD from the Z (friend with a Z is upgrading his) but I want to keep my cruise, I use it a lot.
yes, 3.3 to 3.7 - speedo, tach, cc, everything works fine...
 
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Old Dec 17, 2009 | 06:54 PM
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Originally Posted by AARONHL
I hear ya, I was thinking about buying a Frontier rear dif to disassemble. Would that be possible?
pita but possible sure.
 
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Old Dec 17, 2009 | 07:01 PM
  #81  
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Originally Posted by DaveB
On page one, there is a lot of confusion regarding OEM FDs. Per Post #17:



I posted up the info to clear this confusion regarding OEM FDs. That was obvious to everyone except yourself. No crap rpms will be different if you've got a non-OEM spec FD. Next time, I'll make it a point to very clear for the automotive noobs like yourself that need a lot of hand holding to get caught up on this stuff
since you arent capable of accepting simple logic... I'll just do it this way:

Originally Posted by DaveB

Minor differences in RWD 5AT rpms in 5th at 80mph can be attributed to the following:

1) Worn tires (ie shorter)
2) Shorter tires than stock
3) Taller tires than stock
4) Torque converter locked
5) Torque converter unlocked
6) Torque converter in slip-lock
7) non-OEM FD was installed
 
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Old Dec 17, 2009 | 07:04 PM
  #82  
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^ Illogical logic does not compute Just busting your chops.
 
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Old Dec 17, 2009 | 07:17 PM
  #83  
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Originally Posted by nfsp1
^Yeah, 79 is the magic number LOL!

I don't think it will be too hard. I built a digital speedometer for my Trans-Am, so I'm used to dealing with a VSS. Only trick will be generating the 'fake' signal in a way that the ECM/TCM will still read it. I don't know anyone locally that has a swapped diff so I guess it'll just have to wait until I do mine.
might as well wait until you install the new FD... you never know (and some people might be surprised), maybe your cc will work fine. No point in creating something that you're not 100% certain you need yet.
 
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Old Dec 17, 2009 | 07:26 PM
  #84  
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Originally Posted by OCG35
might as well wait until you install the new FD... you never know (and some people might be surprised), maybe your cc will work fine. No point in creating something that you're not 100% certain you need yet.
my thoughts exactly. Besides, I can't build it unless I change my fd anyway, because I won't be able to test it
 
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Old Dec 17, 2009 | 11:22 PM
  #85  
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Originally Posted by DaveB
On page one, there is a lot of confusion regarding OEM FDs. Per Post #17:



I posted up the info to clear this confusion regarding OEM FDs. That was obvious to everyone except yourself. No crap rpms will be different if you've got a non-OEM spec FD. Next time, I'll make it a point to very clear for the automotive noobs like yourself that need a lot of hand holding to get caught up on this stuff
You pull way too much info out of yours and other people's @$$.

You're posted up info is not necessarily correct. There are discrepancies with many people who never changed anything.

Stop regurgitating what you do not know for a fact please. Or go to some other thread to troll.
 
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Old Dec 17, 2009 | 11:25 PM
  #86  
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^Fight fight fight fight!!!

(I know, I shouldn't incite)
 
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Old Dec 17, 2009 | 11:32 PM
  #87  
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I swear every thread I go to that I see DaveB it's the same thing.
 
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Old Dec 18, 2009 | 01:18 PM
  #88  
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Originally Posted by DaveB
Just to clear things up.

03-06 RWD 5AT Sedan (open or VLSD) - 3.3 gear
03-07 RWD 5AT coupe (VLSD) - 3.3 gear
04-06 AWD (open) - 3.5 gear
All 6MTs (open or VSLD) - 3.5 gear

Minor differences in RWD 5AT rpms in 5th at 80mph can be attributed to the following:

1) Worn tires (ie shorter)
2) Shorter tires than stock
3) Taller tires than stock
4) Torque converter locked
5) Torque converter unlocked
6) Torque converter in slip-lock
My stock '05 5AT coupe didn't have a VLSD.
 
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Old Dec 18, 2009 | 01:19 PM
  #89  
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Originally Posted by Tollboothwilley
I swear every thread I go to that I see DaveB it's the same thing.
finally its not only me...
 
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Old Dec 18, 2009 | 01:21 PM
  #90  
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Originally Posted by nfsp1
^Fight fight fight fight!!!

(I know, I shouldn't incite)
are you kidding... entice away - I'm sure there is an entire community tiered of the squabble between Me, Dave and Jeff... Change is refreshing! And confirming
 
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