2007 Chevy 3500 classic 4l80e

[chilson450]

I've been dealing with torque converter issues on this transmission. I bought the truck running rough and the torque converter not locking. I did a bunch of work to it and got it running better but still no lock up. I was thinking it was the misfiring preventing the lockup. I ended up putting brake switch in it and ended up getting a code for transmission slip. Sorry I can't remember the exact code number right now. I ended up taking a chance and putting a used gm torque converter in I found on marketplace. It got rid of the code and it now locks up. The problem is whenever it is in the process of locking, it buzzes or vibrates. It does it whenever it's trying to lock in 3rd or 4th gear. Once it's locked it doesnt unlock unless it should normally. I'm guessing it might have something to do with the tcc valve in the valve body. I know sonnax has repair kits because valve body wear is common on these.

I don't want to dump a ton of money in this tranny because I don't know the condition of the rest of the tranny. It does have 235,000 miles. But if I can possibly fix this lockup issues with one of these fairly cheap repair kits.

Since I didn't have any core charge on the converter, I cut it open and did find a good chunk of the clutch material missing. I know when converters let go like this it usually sends a bunch of trash through the trans.

Anyone have any input?
Thanks

 

[LDM]

I'm sure one of the GM auto trans guys will chime in but to me it sounds like it needs a full rebuild. The 4L80e is a strong transmission but like anything else lack of maintenance and abuse can kill it like any other transmission. If there was a lot of clutch material in the converter I don't think any kit is going to save it. If the engine and truck are still in good shape to still use, shop around your area for a rebuild/replacement. If its not worth it, sounds like it may be a part out truck at this point.

 

[nascarnation]

I'd suggest changing the trans filter (that's where all the lockup mat'l is unless somebody did it previously) and throw in some Lubegard shudder fix. Refilling with a thicker Dex 3 equivalent fluid won't hurt either. Beyond that, you're probably correct about needing hardware repairs.

 

[SubieRubyRoo]

@clinebarger

 

[paulo57509]

When I rebuilt the 4L60e in the Safari and went shopping for a rebuilt converter, I came to realize that there were more than a few different clutch materials used in the converter. I was just told to match the letter code (DCNF) from the existing one with the rebuilt one. I don't know what happens if there's a mismatch.

 

[clinebarger]

@clinebarger

A used unknown torque converter is a roll of the dice....A Sonnax TCC Regulator Valve is worth a shot, But I have my doubts it fixes the issue.

I would tune out the PWM ramped apply by setting the minimum TCC PWM table to 100% across the board using HP-Tuners.

If this converter has a Cellulose "Paper" Friction in it...Trying to ramp up apply will cause Chattering/Shuddering & premature wear of the Friction Lining, Maxing out the Minimum PWM Table will turn it into a on/off apply.