What are the options for achieving torque converter lock up in 1st and 2nd gear? I'm installing an exhaust brake and I'm thinking this might come in handy.

There is a switch you can rig up. However, I found that it threw a lot of codes on my trans. I will try to recall where that write up is for it. I want to say TST had it on their site somewhere. ATS has a "pilot" system that they sell but its pricey. You also may want to look into whether or not your converter will have 1) line pressure and 2) enough clutch to hold and not slip when using the brake.

As for the torque convertor lock up switch, you need a 33 ohm resister in line with the switch to ground to avoid the codes & reinstalling the relay. From my searching, there is a valve body mod for the 2nd gear lockup, but I havent seen one for 1st gear, as of yet.Ed

I've got the OD switch mod and the LU switch mod. the TCC LU will only activate in 3rd and OD.

I have the 'mystery' switch already but it only locks in 3 and 4. Ed where did you find valve body mod? My searching didn't yield any results for that.

I have a Georend trans. and can lock in 2 nd to 4th gears. As I understand Georend trans can also mod the trans to lockup in first as well but must be notified before they build the trans.. Stock trans will only lock in 3rd and 4th gears however most aftermarket valve bodies or shift kits can give you 2nd gear lockup.

The 2nd gear lockup was in one of the 20-30 trans threads that I searched on looking for info on shift kits. Someone had the info on what to plug with epoxy, I think...Ed