Converter lockup issue, need input on what it is...

[jmgak47]

Starting a day or so ago my converter stopped locking up in my daily which has a 4L60e in it, or so I thought.

As I test I decided to hook up my HP Tuners and try locking up the converter with it @ 70 mph. Seemed to notice a slight change in RPM but couldn't be sure...

So I checked @ idle knowing that if I lock up the converter it will stall and die. Well my driveway is steep, truck was sitting still in D and when I locked up the converter the motor changed tone then started up the incline. Turned off the lockup and the truck stopped moving. Tried this several times...

So it seems the PCM is commanding lockup, the solenoid is enabling lockup, but the converter is slipping during lockup.

Fluid is clean off the dipstick and the truck drives 100% normal other then that, zero shutter even and no codes.

My guess is the converters lockup clutches are wore out???

Regardless I have a Circle D 278 mm 3200 on the way to replace my Edge 245 mm 2600, converters lockup surface was to small IMO anyway and prevented me from towing.

Also for a note, a week before, my tuner made the mistake locking the converter @ WOT. This happened on several pulls, thought it was a shifting issues till I looked @ the tune... *face palm* may be to blame.

Any input or incite on this would be helpful. Have searched and searched to no avail.

Thanks

Jay

[Carazy]

If you have a way to monitor data look at the TCC Slip RPM when the TCC Duty% climbs to 100. A good speed to monitor this at is above 50mph at a steady cruise. You should be around 0 slip when clutch is at almost full duty.

Locking the TCC at a stand still may not work like the old cars because it may need 3rd clutch feed oil to allow lockup. You get lockup in 3rd and 4th only.

[jmgak47]

If you have a way to monitor data look at the TCC Slip RPM when the TCC Duty% climbs to 100. A good speed to monitor this at is above 50mph at a steady cruise. You should be around 0 slip when clutch is at almost full duty.

Locking the TCC at a stand still may not work like the old cars because it may need 3rd clutch feed oil to allow lockup. You get lockup in 3rd and 4th only.

With HP Tuners you can lock it @ idle and it will die if its in gear or at least it did on mine. I was goofing around with it when I got it and thought... hmmm lock converter and tried it so I know it will kill the motor.

I am 100% sure its slipping, just not sure why.

Would do more testing but am afraid of circulating trash through the trans if there is any. Transmission is a fresh rebuild with around 300 miles on it.

[Carazy]

Its tough to diagnos without data now. Whaat year 60E?

[jmgak47]

Its tough to diagnos without data now. Whaat year 60E?

The truck is a 04 GMC VHO not sure the core used. Its a Jakes Level 3

[jmgak47]

Converter is here, kinda late in the day but debating on setting up some lights and attempting it tonight.

Fingers crossed this fixes it...