After installing the sonnax tonight about an hour ago, I figured I'd hop on the forum and just share my experience. Now after searching and researching and bouncing back and forth between a Transgo shift kit and doing just the sonnax pressure booster, I decided to go with the Sonnax for the simplicity of the install. Whereas the Transgo would've required the removal of the valve body.

After looking around online I couldn't figure out which pressure booster was for my 45rfe tranny. Every picture I found for the "45rfe" showed two different versions. It turns out that the LB2(three black wires) is the correct one for the 4/545rfe and the LB1(two black, 1 green) is for the 68rfe.

Now I don't have any pictures but the plug you want is on the passenger side of the tranny where the exhaust collector is. Just gently bend back the heat shield that protects the harness and plug. Then unplug the harness and plug the harness into the end of the sonnax and plug the sonnax back into the tranny. Gently bend the heat shield back into place and make sure the plugs are tucked away neatly behind it. That completes that install.

Now onto the actual reason for the thread haha. The shifts now feel much firmer and even a little quicker. Even in the lower rpms you can feel the firmness of the shifts. I'm not usually hammering around town but where I live the on-ramps for the highways are usually quite short so a heavier foot is required to merge safely. I always disliked the slush box under the truck. I even found myself letting off the throttle mid-shift because it was just taking so long. But I'm quite happy with the shifts now. I've got a stock 4.7 and maybe later when I start doing power-adders I'll think about doing a Transgo shift kit install as well but for right now I'm 100% pleased. For $55 its an investment well made and well worth it. I'd recommend it to anyone looking for a cheap and easy upgrade.

 

I just bought one of these myself and it'll be two weeks before I'm home and get to work on installing it. Now I'm really excited for it, I've hated the slushbox too. It nearly made me buy a different vehicle. My friends and I used to "race" our old vehicles to see who had the fastest one. If missing a cylinder, burning oil, 3.55 gears, 250k miles and 4.5k curb weight wasn't bad enough. The slushbox takes sometimes 1-2 seconds to shift under hard throttle.

I'm really curious to see one day what a transgo shift kit and sonnax booster feel like. If you do get a transgo later, could you message me with your results on that too? I'm hoping they compliment each other.

 

Absolutely. In order to fully install the Transgo you need to drop the whole Tranny because you need to solder in a resistor. I'm assuming that the resistor they want you to drop the tranny for is the resistor that's in the Sonnax. And if that turns out to be the case, then now I only need to drop the valvebody.