4L60E Delayed Shifting If Launched
4L60E Delayed Shifting If Launched My 99 Z will usually shift at the commanded rpm/speed on the 1-2 and 2-3 shifts if I punch it from a roll. If I launch the car it shifts well beyond where I have it set. My shift points are at 6000 rpm with the corresponding speeds for each shift but the 1-2 shift won't happen until atleast 6400 up to 6500. The 2-3 isn't as bad but still delayed, 6300-6350. Is it time to replace it or is there something i can do to fix it? Fwiw I have tried lowering the rpm and shift speeds all the way down to 5500 rpm with no change, it just does what it wants.
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From: BERWICK PA
I am assuming you have tuning software and data capability to know what you do with the command to shift times and have monitored this.
Possible causes would be of course badly worn clutches/frictions.
But more likely AFL issues. . If it was worse on the 2-3 I would say too much AFL and flooding solenoids . But because its worse on the 1-2 I would suspect LOW AFL from a badly leaking AFL valve and low AFL feed to the solenoids .
Your 2-3 shift time is typical for a stock 2-3 valve timing sounds close to what I would suspect little over but 3-4 set may be a little tired.
The 1-2 takes considerable more force to apply the 1-2 valve, So I would say Worn AFL . But other possible causes are Leaky oings on the 1-2 solenoid or leaky orings or damaged screen in pump.
Things you could try short of a removal rebuild are- Replace the AFL valve with a GENTLY OVERSIZED ONE from global https://globaltransmissionparts.com/...CZBBr_WUExhrZo.
Replace orings on shift solenoids or solenoids themselves
Possible causes would be of course badly worn clutches/frictions.
But more likely AFL issues. . If it was worse on the 2-3 I would say too much AFL and flooding solenoids . But because its worse on the 1-2 I would suspect LOW AFL from a badly leaking AFL valve and low AFL feed to the solenoids .
Your 2-3 shift time is typical for a stock 2-3 valve timing sounds close to what I would suspect little over but 3-4 set may be a little tired.
The 1-2 takes considerable more force to apply the 1-2 valve, So I would say Worn AFL . But other possible causes are Leaky oings on the 1-2 solenoid or leaky orings or damaged screen in pump.
Things you could try short of a removal rebuild are- Replace the AFL valve with a GENTLY OVERSIZED ONE from global https://globaltransmissionparts.com/...CZBBr_WUExhrZo.
Replace orings on shift solenoids or solenoids themselves
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Frank formerly of Performabuilt, Now just me, What can I build for you today? Call or message me. Click sig pic for my facebook
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From: Poplarville, MS
If buying a transmission, check out Frank's Custom Transmissions. Frank is a sponsor here and is always in the forum giving out his professional advice. If that's not enough, I don't think you will find a better transmission elsewhere. You owe it to yourself to check out what he has to offer. Contact info is a few replies before this one.
If buying a transmission, check out Frank's Custom Transmissions. Frank is a sponsor here and is always in the forum giving out his professional advice. If that's not enough, I don't think you will find a better transmission elsewhere. You owe it to yourself to check out what he has to offer. Contact info is a few replies before this one.
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From: Ann Arbor, MI
Are you sure you are setting the WOT shift points and not just the part-throttle table?
Also, what many people miss, is that the trans won't shift until BOTH (!!!) the WOT RPM and WOT MPH table values are met. For this reason, I generally set my WOT MPH about 20% below what I need so that any changes to the WOT RPM will change the shift point. (Note: some tuners set the WOT MPH to zero to avoid this problem; I don't know if it has any strange results; I just set mine 20% below what is needed.)
Also, what many people miss, is that the trans won't shift until BOTH (!!!) the WOT RPM and WOT MPH table values are met. For this reason, I generally set my WOT MPH about 20% below what I need so that any changes to the WOT RPM will change the shift point. (Note: some tuners set the WOT MPH to zero to avoid this problem; I don't know if it has any strange results; I just set mine 20% below what is needed.)
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