4L80E Trans Tuning, Possibl to reverence MAP instead of TPS??

[tdmkr496]

Just curious if it is possible to reference MAP for transmission pressure instead of TPS. I have a turbo car and often times at part throttle it can make boost which may cause the trans to slip.

[joecar]

Transmission line pressure is indirectly derived from calculated engine torque (which is calculated from some combination of MAP and TPS).


If your trans is slipping, connect a pressure gauge to the line tap on the side of the case and check how low pressure is dropping to.


If your VE/MAF tune is not correct, the calculated engine torque will go too low which will cause line pressure to go too low... log GM.TRQENG and GM.TFMPRS.


Your trans may have a leaky pressure regulator valve, or it may have other problems like leaky accumulators.