PCV Valve and transmission shift (?)

Joined
Oct 30, 2005
Messages
2,056
Location
South Dakota
I purchased my 2000 Chevrolet Silverado LS (5.3 Vortec, automatic transmission) in March with 183k miles. The previous owner had a rebuilt transmission put in or had the transmission totally rebuilt. The transmission tended to shift harsh. My mechanic stated that the previous owner may have had a shifter kit installed, which would cause harsh or delayed shift.

I changed my oil at the time of purchase with Mobil1 Hm Synthetic and Auto-Rx. I changed it again in October with Valvoline R&P. There were no signs of oil usage with the Mobil1. With the Valvoline there was 1 quart of consumption at about 1900 miles. After posting here, I replaced the PCV valve with the fixed orifice PCV valve. The old AC Delco moved but seemed sticky/gummy.

Since changing the PCV the transmission seems to shift much smoother. Could it be that the PCV was sticking and affecting the vacuum? Can the PCV affect transmission shift?
 
Well it has both a MAF and a MAP sensor so I'd expect it to listen to MAF more. I pretty much doubt it would have much effect, but here you are saying it does, so... :unsure:
 
Will double check the tranny shifting in the morning while the vehicle is cold, but it most definitely seems to be shifting MUCH more smoothly than before!
 
Well it has both a MAF and a MAP sensor so I'd expect it to listen to MAF more. I pretty much doubt it would have much effect, but here you are saying it does, so... :unsure:

Line Pressure/Shift Pressure is calculated based on Load which is calculated off the MAF input unless a P0101/P0102 DTC is set....Then Engine Load is calculated off the MAP (Speed Density)
 
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