Bad converter or something else? No DTC's

[LBZLT3]

Recently went on a long 300-mile drive and when I finally came to a stop, I heard a whining noise, almost like a PTO. As soon as I shifted into N or P it went away and I felt the truck relax. So, I figured the TC was going or maybe the VB or Solenoids were clogged etc. I dropped the pan, other than the fluid being slightly dirty, there wasn't any debris in it. I would have figured I would see something in there. It was clean as a whistle. I even strained the fluid with a super fine mesh. So, I bought all new OE solenoids, manifold and a transgo while I was in there. Cracked the VB open to make sure to clean the filter in there too. All really clean. It's reassembled now and it does the same exact thing still. Looking at the live data, the TCC command pressure is 0 at idle. I wasn't able to find a table to go off of for these values to confirm if it was correct. My thoughts are, either it's a wiring issue or TC. I kind of think I caught it early since there wasn't anything in the pan as far as debris. Any thoughts? I should have checked the internal harness while it was apart, but I was kind of rushing to get this back together.

 

[2004LB7]

Have you logged converter RPM/slip?

 

[LBZLT3]

Have you logged converter RPM/slip?

Yea, the zero slip is park. The other is in drive.

 

[PureHybrid]

Logging slip at a standstill won't do any good as the clutch should not be trying to apply. The pictures you posted look correct though, in drive or reverse the turbine speed should drop to zero until you start to move

Going by your user name, it's a 6 speed truck? Do you use elevated idle a lot during cold months?

 

[LBZLT3]

Logging slip at a standstill won't do any good as the clutch should not be trying to apply. The pictures you posted look correct though, in drive or reverse the turbine speed should drop to zero until you start to move

Going by your user name, it's a 6 speed truck? Do you use elevated idle a lot during cold months?

I use high idle when its cold, yea. Someone mentioned the sprag could be shot inside the TC. There is zero slip at all. Well, i mean theres some because it doesnt stall but you know what i mean.

 

[PureHybrid]

IIRC during high idle the TCM starts to trim the TCC solenoid on to create a little load on the engine to aid in warmup. Caused some premature converter failure. Related to your issue?? Maybe not.

If the converter is failing the debris will be sent to the cooler first, pan usually stays clean. Remove bottom cooler connection at the radiator and look for debris stuck in the cooler fins.

Honestly it's probably pump noise you're hearing