Techlink for the 6L80 thermal bypass valve

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swathdiver

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See a GM notice on a temperature controller for the 6 speed transmissions that should be looked at, changed if it is the higher temp. bypass valve. For the later model Tahoes, not the 21s.

It lowers the temp finally. Most folks that pay attention just flip the original one over so it runs even cooler like the 900s.
 

Doubeleive

Wes
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I fixed mine open, took out the internals, tapped it and put a bolt in it. permanent fix, that and b&m deep pan and a tru cool 40k
now it rarely see's over 145deg
 

swathdiver

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I fixed mine open, took out the internals, tapped it and put a bolt in it. permanent fix, that and b&m deep pan and a tru cool 40k
now it rarely see's over 145deg
Is the cavity open or divided so that the fluid will flow out to the coolers and back into the transmission?
 

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Wes
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Is the cavity open or divided so that the fluid will flow out to the coolers and back into the transmission?
it works sort of like a coolant thermostat except that it only allows internal fluid flow until reaches at least 180 deg then the spring releases and allows flow out to the cooler and back, when I put the bolt in it makes it so it can flow to the cooler all the time and the thermostat function is bypassed.
found a diagram not sure it's notated correctly, but where I put the black circle and black arrow is where I taped it and inserted a short bolt to block off the internal only flow and make it run to the cooler all the time if that makes sense. the green circled part is removed, this leaves nothing in the way to block flow in & out to the cooler
thermostat.JPG
 

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swathdiver

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it works sort of like a coolant thermostat except that it only allows internal fluid flow until reaches at least 180 deg then the spring releases and allows flow out to the cooler and back, when I put the bolt in it makes it so it can flow to the cooler all the time and the thermostat function is bypassed.
found a diagram not sure it's notated correctly, but where I put the black circle and black arrow is where I taped it and inserted a short bolt to block off the internal only flow and make it run to the cooler all the time if that makes sense. the green circled part is removed, this leaves nothing in the way to block flow in & out to the cooler
View attachment 357105
I get it Wes, thanks for the clarification.
 

Foggy

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My 2014 did NOT have this from the factory... I even confirmed it with
my trans builder when he built my cirlce D stage 4 trans
I was concerned about this "thermostat" thing.. But I don't know which years
or models had it for sure
 

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