4L80E Hard 1-2 Shift

[clinebarger]

Okay, Not horribly high mileage.

Wouldn't be a bad idea to try a TCC Solenoid & a Sonnax drop-in TCC Regulator Valve.

The TCC itself do fail, Quite a bit more frequently than 4L60E units of the same years at least in part because the calibration.

Anytime the TPS is below 5% throttle angle....4L80's cancel lock-up. So if you drive say 300 miles, Every time you let off the throttle, The converter unlocks....Them "PWM's" back into lock-up, Depending on one's driving habits.....The TCC could've experienced a 1000 on/off cycles.

There IS a reason it's calibrated that way, Let's say you're fully loaded to GCWR & headed down a long grade At zero/closed throttle.....You only have 60-70 PSI available to keep the TCC locked.

Have you dropped the pan?

 

[Peteco]

Maxlife and Lubegard red helped fix my 1/2 harsh shift in my 4l60, could also add a tube or 2 of Lubegard Shudder Fixx instead of the Red. I'd try that route.

I am using Maxlife and Lubeguard red. It’s at 50,000 since last change. I was planning to switch to Dexron VI.

 

[wlk]

I am using Maxlife and Lubeguard red. It’s at 50,000 since last change. I was planning to switch to Dexron VI.

I wouldn't let it go that long personally, I do 30k changes myself. I would try a drain or 2 and see how it goes.

 

[Peteco]

Okay, Not horribly high mileage.

Wouldn't be a bad idea to try a TCC Solenoid & a Sonnax drop-in TCC Regulator Valve.

The TCC itself do fail, Quite a bit more frequently than 4L60E units of the same years at least in part because the calibration.

Anytime the TPS is below 5% throttle angle....4L80's cancel lock-up. So if you drive say 300 miles, Every time you let off the throttle, The converter unlocks....Them "PWM's" back into lock-up, Depending on one's driving habits.....The TCC could've experienced a 1000 on/off cycles.

There IS a reason it's calibrated that way, Let's say you're fully loaded to GCWR & headed down a long grade At zero/closed throttle.....You only have 60-70 PSI available to keep the TCC locked.

Have you dropped the pan?

I’m 800 miles away from home with planned return early April. Not sure I can find a place to drop the pan on my own while I’m here.

I had been thinking about the Transgo TCC valve that you have mentioned in the past. Also check or replace TCC valve solenoid and connector /wiring. So is the Sonnax your recommended valve? Doesn’t that require reaming, which would be no problem if I were home.