Just installed a built by me 4L80E with a Circle D multi-disk TC. It has the HD-2 shift kit, internal dual feed, all new clutches, bushings, etc. Because of the internal dual feed, I didn't install the 3-layer separator plate, used a Transgo HD plate instead.

It drives well, all gears work, shifts okay (needs some tuning), but I have no TCC lockup, not even a smidgen.

I'm trying to force lockup with EFILive while driving and nothing! I can hear a very faint click when I turn the solenoid on with EFILive, but it's much much quieter than the shift solenoids. According to the log I took it tried to lock it up on its own too and nada.

Solenoids are all new, no codes, pressures seem okay. I get around 60-70psi at idle warm, and regularly gets around 150psi on the throttle, but I didn't watch the pressure gauge too much.

 

UPDATE:

I hardwired the TCC signal wire (pin S) to a switch to ground it when I want. When I turn it on while driving at lowish throttle nothing happens. But as soon as I increase throttle it starts to grab and the RPMs drop. If I give it enough throttle it will almost totally grab, the TC slip will drop to around ~100 RPM. I did this a couple times to verify my results, hope this didn't do too much damage to the converter.

So it sounds like its a mechanical issue within the trans. Anyone have ideas of where to start looking? I'd like to start with the things that are easy to get to such as the valve body. But I fear it might be the stupid o-ring on the input shaft. Bummer.

 

Pressure seems low to start with, using the hd2 and dual feed mod might cause problems, people do one or the other, the 3 layer seperator plate is a no no it can cause internal leaks. If trying to force lockup with efi live then something is wrong for sure somewhere. Maybe Jake or someone else can help you, but it sounds like a few different things can be combined to cause this problem.

 

An update on pressure is ~90psi cruising in OD, 60psi neutral idle, and gets up to 200psi at WOT.

I actually did the dual-feed internally by blocking off the reverse passage in the case, removing the inner seal on the direct piston, removing the seal on the center support shaft, and also drilled a small hole in the outside of the direct drum. I left out the 3-layer plate and used a single layer instead.

There does seems to be many things that could cause this. I'm going to start with things I can access by dropping the pan.

 

I think your pressures are way too low. Mine at idle hot is around 175-180psi while in neutral. I gear its a bit higher. I know low pressure will not allow the tcc to engage. I would try upping the pressure via the regulator and see what it does.

 

Honestly I have no clue what a "normal" line pressure would be for this trans. I did some searching and only found this link, which indicates that my pressures are okay. http://www.trucktransdiag.com/downlo...-tech-info.pdf

Did you do any mods or tuning to up the pressures? What RPM do you idle at? Mine idles at around 700 RPM.

Based on my testing, I need somewhere around 200psi of line pressure to fully apply the TCC, and probably even more to for it to hold any decent amount of power.

 

My pressures are based upon what my builder, Elitesnipez, told me to set it to. He told me around 175psi at idle. My car idles at 800-850 rpms. I know low line pressure can cause no tcc apply. Whether you have an internal leak causing the low pressures, or the pressure contorl regulator is another story. My trans has a lot of mods done to it. Dual feed direct, fully rollerized, billet clutch hub. It had an hd2 shift kit and my builder frowned on it and we took it out. It has a different valve body in it now, a single non stacked seperator plate and duel feed directs. We got it in the car and running and pressures were about 30psi lower than what they are now. He told me to adjust the pressures regulator to get a little more pressure out of it. I did and he was happy with what it is now.

 

Are you using the PCM to control it?

 

Your pressures sound OK.

TCC should work even at minimal line pressure at cruise, which could be as low as 70-80 psi at very low TPS settings.

You may have a converter with a bad lockup seal, bad seal on the input shaft, etc.
The lockup circuit has more potential problem areas than any other circuit on this transmission. It's one of the areas that we've spent the time to make our builds work better than most.

Make sure the o-ring on the solenoid is in place and not damaged.

 

There isn't any need to run max line pressure at all times. If you have a controller operating your transmission, you can tune your pressures and I would suggest doing so, not leaving it max'ed out adding strain to the pump.

I also HIGHLY doubt your unit is "fully" rollerized. That's a lot of machining and specialty parts.

 

Thanks Jake. I'm planning on pulling out the valve body and checking everything (I need to drill out the spacer plate some more anyways), and the TCC and boost valves from the pump. If that doesn't work then out comes the trans and converter