4L60e will not upshift at WOT
03-02-2012, 07:27 PM
#21
The speedo will never "correct itself" it uses the information programmed into the computer...
Also unless theres a HUGE height difference btw the 17 and 18s it would not cause a 15mph discrepancy. So if its off with the 18s it was probably almost just as bad with the 17s...
Get that corrected in the tune and see what happens. Also unplug the MAF and see if it shifts any differently..
Also unless theres a HUGE height difference btw the 17 and 18s it would not cause a 15mph discrepancy. So if its off with the 18s it was probably almost just as bad with the 17s...
Get that corrected in the tune and see what happens. Also unplug the MAF and see if it shifts any differently..
03-02-2012, 08:18 PM
#22
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You changed tire size and your speedometer is off 15 MPH.
Your transmission still thinks it has the tires on for which its tuned for thus all your shift tables off.
If you still have your old tires and rims which your tranny didnt have an issue with, install them back on, and see if your shifts and speedometer is correct.
Your transmission still thinks it has the tires on for which its tuned for thus all your shift tables off.
If you still have your old tires and rims which your tranny didnt have an issue with, install them back on, and see if your shifts and speedometer is correct.
I wish I had't mentioned the speedo being off now for the confusion lol.
Here is a timeline
Jan 10'-new lS6 crate engine installed with new PCM tune
Trans shifts perfect
May 11-trans will not up shift at WOT all of a sudden trans then starts to slip loses 3-4 clutches car sits until
Feb 12- trans is rebuilt when car is driven out of trans shop I notice still no up shift at WOT mechanic says its computer. I drive car to house(speedo is correct)park it and send PCM for retune for headers, converter, 18 inch rear tires and to possibly correct WOT problem.
Last week-install retuned PCM, no WOT fix and speedo is now 15mph at 80
I can try unplugging the MAF see if that helps??
03-03-2012, 07:55 AM
#23
Hmnn... 1-2 shift does not happen at WOT until you let off the gas: Best case: try replacing the TPS. Middle case: leak in the 2nd gear apply circuit (servo assembly or 1-2 accumulator). Doublecheck by using the pressure gauge and watch for a big drop when the PCM commands 2nd gear. Worst case: poor line pressure rise...
What's changing in this scenario??
1. The TPS volts.
A scan of the system will tell U hats up w/ that.
A trans psi scan will cover the leaks/broken parts scenario.
03-03-2012, 08:30 AM
#24
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I showed the mechanic the same thing you just posted, he checked tps there are no codes and voltage is correct. I asked him if it can be the leaking 1-2 accumulator valve he said no because it doesn't upshift when it downshifts from any gear at wot.
03-04-2012, 01:03 PM
#26
I would not waste the time taking the car to a trans shop. The problem is into the tune itself. In order for the car to shift. U have to recalibrate the speedo for whatever tire, or gear change you do. U should really have a professional tuner look at your tune. I had this same problem for over a year until I talkd to a tuner. So honestly you will b waisting money taking the car to a trans shop or replacing the pcm.
03-04-2012, 01:24 PM
#27
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How is the tune going to detune itself to upshift at WOT to not upshift at WOT over the course of time? Like I said the trans wasn't upshifting at WOT for a whole year with a correct speedo it's just this last tune the speedo got screwed up
03-04-2012, 06:26 PM
#28
what are you using to see how far off the speedo is, are you using a computer or hptuners. im just saying that when it comes for the trans to shift correctly you have to have all the tables looking exactly the same, whether it be wot or part thottle. even if you have one table off just a alittle it will cause the car not to shift. can u post ur tune so someone can take a look at it to see if they see anything awkard that could help you.
by the way who did your tune on ur car.
by the way who did your tune on ur car.
03-06-2012, 11:08 AM
#32
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Um yeah I took it back twice...driving the car out of the shop originally 3 weeks ago and turning around then again last week after I got my PCM back. Both times the mechanic said it's the computer not the trans. I just took my car to another trans shop today and the mechanic said it's probably the seperator plate inside the valve body where the shift kit was installed. So basically I may have a trans mechanic telling me it's the computer so he doesn't have to do any free warranty work and another trans guy telling me it's the trans to get some work. I don't think the tuner is trying to sell me a pcm I don't need because I could just buy another pcm and send it to him but he may be wrong about it being the pcm. The trans downshifts and upshifts at 3/4 throttle and that's what I don't get.
03-06-2012, 06:28 PM
#34
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If its the transmission why is the builder telling me he's 100% positive it's not the trans and according to his scanner the PCM isn't commanding the up shift at WOT? I guess my next step is taking it to another shop that has a scanner that can check.
03-30-2012, 03:18 PM
#38
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If its the trans why was it doing it before the rebuild and why are two different scanners saying the trans is not getting the upshift command at WOT?
03-31-2012, 04:42 PM
#39
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I spoke with someone off here who I bought the PCM from he said he has his own race shop and knows a thing or two. I told him the shift kit was re used in the rebuild and did not upshifts right before and after the rebuild and feels its the check ball in the valve body..drilling the holes out for the shift kit and its gotten bigger over time. Another trans guy is telling me the same thing. Will the computer not command the upshift at WOT If a check ball in the valve body is loose?
03-31-2012, 05:08 PM
#40
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My input would be the before it was needing a rebuild and the after the rebuild isnt right. Im no trans guy. But have dealt with a stack of these... and 99% of the time WOT No upshift is trans bad. If you slighty let of the pedal it will shift but not at WOT. That is my usual test drive on a high mileage LSX for my friends to buy it.