Controlling torque converter lockup 2

[rikakiah]

Ok, I'm probably over my head here as I doubt I'm as technical as many of you, but here goes...

Is there a way to directly control when the coverter locks up (I'm assuming by way of the torque converter clutch circuit?)? For example, for a car (Ford, if it matters) that normally only locks up in 4th, is there a way to apply voltage (or remove voltage) from the TCC circuit in order to force lockup in say 3rd or even 2nd? Any specifics would be appreciated. And yes, I realize this is only a limited application deal as I'm sure continual lockup isn't good for tranny longevity.
Thanks

 

[Metalguy]

Update time. I finally got so fed up with my TCC "apply" valve leakage problem (only when hot)that I took a chance and bought a 5 gal. pail of Cat./Allison trans. fluid for "Powershift Trans". I got the 50 wt (thickest avail.). Drained what I could from the 4T60 (about half of what it holds) and poured in the thick stuff. End of problem! So far so good after ~10,000 miles. My simple calc's. indicate that I've made the trans. "think" it's about 40 deg F cooler than it really is. As long as I don't use the van below ~20 deg. F. I should be OK.

 

[jetmech]

I guess I should update my findings also. I did some research and came across the Sonnax website, which was very informative. To make a long story short I installed the PWM TCC regulator & isolator valve kit and TCC apply valve kit. Works great no more problems!!! Both kits, gaskets, fluid and a new filter all for around a hundred dollars. The old TCC apply valve was not worn but the new and improved valve in the kit has a teflon seal on it so why not change it while I'm in there. The PWM TCC regulator & isolator valve was definitely worn. Did not remove the trans. to do it, but I did wind up lowering the drivetrain cradle quite a bit to get the side cover off. I also removed the caliper, steering knuckle, lower control arm and inner fender for accessibility (sure made the job easier.)

 

[modistran]

4T60-E Tcc slip problems are in many cases caused by the teflon sealing rings on the turbine shaft leaking from wear. Always change these rings.This is the case in all lock-up units. Installing thicker fluid just helps slow down the leak.