hi guys,
you surely know that GM improved a lot of parts on 2008 and up 6L80s and other 6 speed transmission.
there is a newer bulletin very interesting:
#09-07-30-004I: Slips in Reverse or Third, Delayed
Reverse or Drive Engagement, DTC P0776, P2715,
P2723, Harsh 2-3 Shifts (Inspect 1-2-3-4 / 3-5-R
Housing and Pump Seal Rings) - (May 10, 2012)
Long story short, I put the newer 1-2-3-4 / 3-5-R Housing p/n 24238694 with newer pump into a 2007 6L80E. the housing has the same parts inside except some piston which have different sizes and so different working pressures.
I upgraded the tune in the pressure area, shift time and some other little stuff (according to the tuning school newest book too) and the shift are firm, no flare at all, good comfort nice to drive (is a totally stock truck, no performance in mind, no performance oriented, daily driver)
BUT when coasting down to low gear if I slowly press the accelerator pedal I have a brutal shift engagement and I don't understand what is the root cause.
any tip looking at the tune?
any tip about the PID that should be scanned to find the root cause?
thank you so much for sharing!
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