4l60e shift problem
07-24-2013, 03:33 PM
#2
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Need more details... will it shift if you try it manually? Does it shift under part throttle okay? If it will shift automatically under part throttle while left in D or 3 but not under heavy, wide open throttle conditions, then chances are it's in the tune.
07-24-2013, 03:53 PM
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It shifts ok at normal driving either manually or in D. Tuner could not get it to change any different. When I say ok its still sluggish. Trans guy thinks shift kit is in order.
07-24-2013, 05:06 PM
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Would be curious to know what your "Shift times" are set to and pressures. Any idea how the transmission was shifting prior to it being swapped into your IROC?
07-24-2013, 10:10 PM
#6
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By "heavy throttle" do you mean WOT? WOT (typically over 96% throttle, but programmable) uses different shift tables that the partial throttle shift tables. If the WOT shift tables were way wrong, it might not shift.
Edwardzracing: Not to hijack this thread, but if you could explain to give a link to "Shift times", that would be appreciated. I know most other trans tuning tables, but have no idea what "Shift times" does.
Edwardzracing: Not to hijack this thread, but if you could explain to give a link to "Shift times", that would be appreciated. I know most other trans tuning tables, but have no idea what "Shift times" does.
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07-25-2013, 07:44 AM
#9
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This sounds like the part-throttle shift tables are way off. This could be because the PCM doesn't know the speed of the car because the rear-end ratio is tuned incorrectly, the VSS is bad, etc.
Is your speedometer connected to the PCM? Is it accurate?
I would use a scanner (like HP Tuners) to view/log what speed the PCM thinks the car is moving at.
Is your speedometer connected to the PCM? Is it accurate?
I would use a scanner (like HP Tuners) to view/log what speed the PCM thinks the car is moving at.
07-28-2013, 11:09 AM
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I have the same problem and i am my tuner. If i set the shift points for wot way low, then it will shift but if i set them to over 6100 rpm then it just blows right by it, hits the limiter hard. I'm very sure its not in the tune. A shift kit seems like a logical solution. I'm really considering a 4l80E for mine but its a heavy truck. I hopes you find a solution and post it up. If it does turn out to be the tune, that will be good news because it will be Ann easy fix.
