[Cliff R]

We've also seen a lot of shops simply direct wire the TCC by grounding it on a normally "open" 4th gear pressure switch. Then you get a shift to 4th and immediately the TCC engages.

The problem with this set-up is that it will not unlock when coasting and any heavy/full throttle driving.

The best set-up I've used in a vacuum switch hooked to a ported source, then to the solenoid, then grounded on a 4th gear pressure switch. One can also route the voltage thru a toggle switch if the operator wants manual control at any point.

With all that said, I'm still not very fond of using a TCC for a well set-up retrofit into an older vehicle. If a good converter is used, the vehicle simply shifts 3 times, and still has some torque multiplication for heavy throttle situations without having to shift back to third gear.

I ran my Impala SS with both set-ups, and I could barely detect any rpm difference cruising on the highway above apprx 50 mph. The tach would move maybe 50-100 rpm or so when climbing a steep grade in OD when additional throttle was applied to maintain speed. I couldn't measure any differences in fuel economy either. I did all this WAY back in the early 1990's. These transmissions weren't all that popular at the time. I bought the first torque converter from Daaco, and blew it to BITS shortly after installing it. I'm pretty sure we bought the custom non-LU unit from Precision Performance. It was a very well built converter, with decent flash stall and very, very well coupled for "normal" driving.

The combination of 3.31 gearing, stout 327 engine, good converter, and the 4L60's 3.06 first gear gave the old Impala a whole new outlook on life. That car was amazingly quick from a stoplight.

A big Pontiac with a 400 or 455 would be even better, and one wouldn't need steep rear gears, 3.23's or even down to 3.08's would be fine......Cliff