95BLKVette

I have a 3,000 stall Pro-Torque 9" Lockup Race Converter which was recently been refreshed, but I've pretty much always had this slippage problem only when the tranny fluid gets above 192F.

TCC goes into and out of lockup fine. It just seems to start slipping when pressing accelerator pedal just a little more than cruise at highway speeds of approximately 60 mph + in 4th w/lockup.

I don't think it's a missfire problem as the engine pulls fine and with PCMComm there's 0.00 degrees knock retard shown and TCC shows as in constant lockup command.

Is there a tuner program that will allow changing thre duty cycle of the TCCPCS valve? Think its slipping cause the stock converters a 12" and this is only a 9" and has alot less lockup clutch surface area, so I want to raise the duty cycle to increase TCC lockup pressure....can't do that in LT-1 edit that i'm aware of.

STL94LT1

I really don't know what you're asking. But, you may be able to find it on Tunercat's site. Click on the vehicles supported, then information. It will tell you everything that can be changed with their software.

http://tunercat.com/tnr_desc/do_tc.html

95BLKVette

Thanks, but I don't see anything in that either

Any tranny tuners ?

VenkmanP

I vaguely think I've read threads on the impalassforum about people changing or disabling the TCC PWM. Since I have a 94 I've never paid that much attention, but you might try a search in the PCM section over there.

However, it sounds like the problem you are describing is when the converter is already locked up, so what would the PWM duty cycle have to do with that? I thought the PWM was entirely about engage/disengage? (But again, since I don't have it, I haven't paid that much attention...)

Another point would be to consider the thousands (probably tens or hundreds of thousands) of people running the 4L60E with high-performance converters, and you never see discussion about having to modify the TCC duty cycle as a result, which makes me think you have some other problem you need to address.

95BLKVette

Thanks for the reply.......

As far as I've read (I'm no expert) the TCC Solenoid is a simple on/off type solenoid valve located in the pump body that is normally open, when the PCM enegizes this solenoid blocking converter clutch signal fluid from exhausting, this creates pressure in the TCC signal fluid circuit. This pressure causes the converter clutch apply valve to move against spring force and into the apply position. Then basically this valve simultaneously exhausts fluid from behind the TCC pressure plate and applies fluid pressure to the torque converter thus applying the TCC.....WOW

Now, the TCC Pressure Wave Modulation (PWM) solenoid ( a pulsed not on/off solenoid) regulates the amount of fluid flow to the converter side of the TCC.....the apply fluid actually leaks past the clutch surface to cool it and exhausts through the turbine shaft via past that little check ball valve you see in the end of the input shaft when the converter is taken off the tranny (BTW, that ball seats when the TCC valve vents fluid from behind the clutch apply plate and this slows the venting and makes for a smooth clutch apply...that's why if you remove that checkball from the end of the shaft the TCC apply will be very harsh).

So, the TCC solenoid applies the TCC through the TCC Valve and the TCC PWM solenoid varies the pressure on the TCC. Otherwise you wouldn't need a TCCPWM solenoid.....IMO they should never have added one in the first place......

At least that's what I can make of it....I didn't go to tranny school you know

So, why isn't the Guru of Trannys chiming in on this thread

edcmat-l1

The PWM solenoid is to smooth the transition into lock up. Once its locked, its locked. If you're experiencing TCC slip while its supposed to be locked up, you've got other issues.
Even though you have less surface area, that shouldnt matter. We've run 10 inch converters locked on the dyno behind 500 rwhp cars, full throttle from 2500 up. No slip. If anything would make one slip, that would.
You may want to find someone with a snap on scanner, or Vetronix master tech, or equivalent. With those you can monitor TCC slippage. I suggest that not knowing what you're using to scan, and whether its capable of that.

95BLKVette

Well I have to hand it to Frank at Performabuilt

He was nice enough to explain how to mechanically lock out my TCC valve.

I got into my tranny today, drilled and pinned the sonnax TCC Valve and walla, no more TCC slippage.

Works perfectly now.

That was really nice of him