Recently picked up a 2003 1500HD with 54k miles on it. The truck is completely stock outside of a tune. Recently I have noticed that while cruising down the interstate, and I let off the throttle, the converter will unlock but sometimes does not want to lock back up right away. It will take some time do so when it eventually does. I went in and changed the tune so it would remain locked when letting off the throttle, but of course it still unlocks when the brake is applied which I knw is normal.

While driving to work this morning I was going 70 mph down the interstate and had to hit the brakes. The converter unlocked, and remained unlocked for a couple of miles when I finally hit my exit. No matter what I did I could not get it to lock back up. Slowing down, going faster, letting off the throttle, etc. Any idea why it is doing this?

Another issue I noticed the other day is when I tried taking off from a stop light and hit the throttle, the engine rpm increased but the truck did not move for a split second. It almost felt as if the tires were spinning. The 4L60E in my Rainier did this a couple of times as well but it had 145k on it and I attributed it to it's age.

Lastly, I have the TCC Duty Cycle max table at 100 and the and min at 50. I used these settings on my Camaro when it was controlled via the stock PCM, and on my Avalanche and Rainier. It always felt like another gear when the converter locked but on the Silverado it still feels weak. Is this normal for a stock internal, stock stall 80E? Should I raise the min table?

Like mentioned above, the truck only has 54k miles on it and is in dang near perfect shape. I know things can start to fail due to age but I figured a stock 80E behind a stock 6.0L would last for quite some time without issue.

I am going to try flashing the stock tune back in it to see if it changes. What else do I need to look at? Solenoids? Valve body?

Thanks for the help.

 

What was the TCC PWM Solenoid commanded duty cycle while the converter should have have been locked? If it stayed at 0%...The PCM isn't commanding lock-up, Several thing can cause this.....Misfires, False load/calculated load, Trans DTC's, False Brake Switch input.
If you can log all these PID's along with TCC slip RPM.....That would be great!

If the TCC PWM Solenoid Duty Cycle got above 70% & the TCC slip RPM remains above 150 RPM...... TCC Solenoid mechanical issues, PCM Driver issues, Worn TCC Regulator Valve/Bore are all possibilities.

Low AFL pressure can cause TCC PWM Solenoid performance issues, But AFL pressure effects ALL solenoids & causes low line pressure before it starts affecting solenoid performance.


Set your minimum TCC Duty Cycle to 99% for better TCC apply feel....Though a 310mm 4L80E converter will never have the same feel as a 245mm high stall that has no damper springs when it locks up.

 

Thank you for the suggestions. I have modified the tune with a higher TCC DC and set it up so it will not show any misfires as well. I will get it loaded and report back with some logs.

 

I always do min 95, max 100 to minimize slip.

 

Are you almost finished wit the 80E install?

 

It is done, basically just waiting on the turbo kit at this point. Im initially going to basically leave the 60e tune in it (segment swap obviously) and see how she does.

 

Pm'ing ya1
Sorry to the OP.