So about time I updated this :augie
First up, the manual torque converter lockup switch.
So the RE4R03A autobox in the Trols is simply a HD version of the autobox in the Terranos (RE4R01A) so it's a 4 speed box, 3 plus overdrive, with torque converter lockup kicking in after overdrive.
TC lockup locks the torque converter into one and so gives you direct drive from the engine into the gearbox. Benefits are more efficiency (ie. lower revs) and less wastage (ie. less heat production).
Normally the TCU (Transmission Control Unit) automatically locks up the TC once you reach cruising speed and revs although only after you've hit 4th speed/overdrive.
The Trol lockup system is notorious for banging in and out of TC lock if you're on anything other than a slight hill. Also, as happened with mine, it is not uncommon for TC lock to suddenly stop working full stop.
My TC lock stopped working except on the very very odd occasion. Nobody is entirely sure why it happens but it seems to be TPS (Throttle Position Sensor) related, at least mine was - I disconnected my TPS, making the TCU go onto a default map based on rev counter and speed et voila! I got TC lock back, although the drive was not the best (changed up very very early).
So TPS was main suspect. I wasn't up for trying to track down a 24v TPS from my parts websites, particularly since the existing TPS worked fine for everything else... so time for a mod I had planned to do at some point anyway!
Starting point is the following circuit diagram by a guy called Chaz. Pin numbers are for a Y61 Trol but the same diagram works for a Y60 as well (P/N pin is 19 whilst the TC lock pin is 22). It is a masterpiece - includes a safety cut out as soon as you press the brake pedal, and disconnects it if you are in Park or Neutral (going into TC lock in either of those is a BAD idea)
You need 4 five point relays like this.
Get a couple of switches and a relay box, and labels, lots and lots of labels so you don't lose track!:lol
You'll see I just went for a standard momentary carling switch instead of a foot switch. By having one with an LED it has meant I don't need a seperate LED!
Power switch on
Momentary switch pressed and relay working :thumbs
Works really really well. I've got a shift kit installed in mine which means I run slightly higher line pressure so I put her into lock once I'm in overdrive at about 55/60 mph and the revs drop nicely down to about 1600/1800rpm (if you aren't running a shift kit you don't want to have lock running at less than 1800rpm as you will wear the lockup clutch due to the pressure being too low).
Once I engage TC lock manually she stays in, hill or not, until I brake. I can even shift between 3rd and 4th whilst in lock (takes a bit of practice/familiarity to make the change up less savage though). Benefit is once I have the towbar back on the Trol I will be able to engage lock even when I'm running in 3rd with overdrive switched off for towing and can make the gearbox run cooler and at lower revs as a result.
