Is my transmission talking to me?

[Marky Dissod]

You should DEFINITELY update, if not upgrade the ATF thermal bypass valve.
Don't know if using 8L90 ATF is necessary,
although I know a guy who's been using it in 4L60s for years with no issues whatsoever.
If you're gonna update / upgrade the ATF thermal bypass valve,
might as well change the ATF & filter.

 

[NickTransmissions]

Doing research on this transmission issue, stutter when accelerating. My Tahoe seems to run fine when the trans temp is reading low, that is below 130.
But as it heats up 180 and above, I notice the stutter is more pronounced. Max temp I have seen is 195, but it was probably much higher a few months ago
when I was towing a cargo trailer. At that time, I did not detect the stutter... I thought it was the usual slack of the trailer hitch noise.

So I am considering replacing the Trans temp bypass valve with an after market product. Currently looking at this...

PPE Transmission Fluid Thermal Bypass Valve(14-18 Tahoe w/ 6L80 Transmission)​

Also considering adding the magic sauce, Instant shudder fix additive to the existing fluid.

I could also replace the trans fluid with GM ACDelco 8L90 Transmission Service FILTER Kit Mobil 1 HP Fluid For Chevy GMC, although I think my tranny is
a 6L80 model. But since this is more complicated, I am favoring the first two options. Should the fluid change be required, I would also replace the filter
and gasket, and hope the pan can be removed without too much trouble.

Thoughts, Advice, Input.... all appreciated!

Run a Superior Tech delete kit. Take it for a test drive with a two-way scan tool plugged in with live trans and converter displayed. Look at TCC slip speed and duty cycle. Slip speed should be no more than 10 rpm at max duty cycle. Also look at engine data for anything unusual like misfires, etc...If the TCC is slipping when in lock up, it will need further diagnosis to determine why it's slipping. You may end up needing a new converter and perhaps an overhaul of the transmission...