transmission issues on a 2008 gmc acadia fwd

JAVINDRA

Original poster
Member
May 27, 2018
71
brampton ontario canada
I HAVE A 2008 GMC ACADIA FWD WITH SERIOUS TRANSMISSION ISSUES. ABOUT 2 MONTHS AGO I HAD THE TRANSMISION REBUILT AFTER 3 FAILED VALVE BODY REPLACEMENTS . I INITIALLY TOOK IT IN FOR A TRANNY FLUSH THEY THEN TOLD ME THE OIL WAS DIRTY AND THAT I NEEDED TO HAVE THE VALVE BODY REBUILT WHICH THEY DID AND IT WAS WORSE SO AFTER 3 FAILED VAVLE BODY OVERHAULS THEY TOLD ME THE TRANNY NEEDS TO BE REBUILT WHICH THEY DID BUT THERE WAS STILL SHIFTING ISSUES SO THEY SENT IT TO THEIR TRANNY AUTOMOTIVE ELECTRICIAN AND HE REPLACED THE HARNESS AND ADDED A COOLER BUT AFTER 2 MONTHS IN THE SHOP I AM STILL HAVING SHIFTING ISSUES AND 3 TRANNY CODES ALL RELATED TO THE FLUID PRESSURE SWITCH...P0842 TRAN FLUID PRES/SWITCH A CIRC LOW … P0872 TRANS FLUID PRES SENSOR/SWITCH C CIRC LOW AND P0877 TRANS FLUID PRES SENSOR/SWITCH CIRC D LOW. MY QUESTION IS I AM STILL GETTING HARSH SHIFTS WHAT DO I TELL THE MECHANIC AND ARE THESE SENSORS /SWITCHES INSIDE THE VALVE BODY OR IS THERE A SINGLE PRESSURE SWITCH CONTROLLING THE FLUID PRESSURE IN THE TRANSMISSION....THANKS FOR ALL REPLIES AND BE SAFE
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
Do us all a favor... AND QUIT YELLING!!! Its extremely hard to read.

Now that thats out of the way.

Has anyone checked the tranny cooler lines for a block/partial block? Or the tranny cooler itself for the same?
 

m.mcmillen

Member
Apr 29, 2016
554
Wisconsin
I had a similar problem once. The pressure sensors are inside the transmission and there are these little screens/diaphragms (circled in red) that break. I replaced the whole module and it took care of the problem. If they did not replace the TCM which is what basically this is, this might be the problem.

Screen Shot 2020-05-08 at 7.19.05 PM.png

Link to Amazon for the part https://www.amazon.com/dp/B01KHLJHP0/?tag=gmtnation-20

This part does have to be programmed.
 
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