3. Transmission pwm failure/tcc solenoid failure/misinterpretation.
After I performed the top 2 repairs, my mpg went from 9.8 to 12.8 with the same driving.
Nowhere close to what i want to be (considering those were majority highway miles [should be somewhere near 16mpg for hwy speeds of 85mph]).
I do notice that whenever i am at high way speeds the 4l70 wont engage full slip, it will only slip partially,
keeping rpms around 200-400 lower then full lockup (im not super well versed in transmissions), which in turn probably tanks hwy mpgs.
Driving my moms charger with a five speed 5.7L (i also know this is hardly comparable) it engages like around a 80% slip at 70-80 mph,
being at 1200 rpm vs full lockup being around 2500 rpm in 5th gear with no throttle applied.
Also on the 6l80 tahoes (09-14) in 6th gear there seems to be a larger slip difference then the 4l70 tahoes.
My tahoe has been through a transmission already, and 2 different pwm tcc solenoid replacements, still throwing a tcc pwm code.
