Opinions on 4L80E converted 6-speed automatics

[Vimes]

It's a shame TCI stopped making their low gear set for the 4L80E. I had one of the 2.75/1.57 sets in and it worked great although I kinda wished I had sprung for the 2.97 one. I had almost the acceleration of the 4L60E without the weakness of elderly hamsters and rubber bands. Plus, the 1-2 drop was about right. The 2.97 would have better acceleration, but the 1-2 drop is pretty close to the 4L60E drop. If you could find anyone that still had one available, that plus the Gear Vendors unit would make a nice setup. The gear spread with the low gearset plus the Gear Vendors unit would be quite a bit better than the plain 4L80E, and you could run a slightly higher (lower numerically) rear gear and get the same takeoff you have now with better mileage, or keep what you have and have a better takeoff with better but not quite as good of mileage as with a plain 4L80E and no GV.

Transmission Center claims to have a 2.97/1.57 one but I'd verify it's correct.

[peterwollman]

I reached out to Jake regarding the Engine Breaking issue on the TCI 6X and whether or not the valve body could be modified to do Engine Braking or if a PCS VBM-2000 4L80e 6-speed valve body was available could work with a TCI 6x to give braking in the electronic shift mode or any other options. He basically wouldn't touch the issue on the 6x, and said just to return it to TCI. I don't believe he thinks much is good about the TCI 6x. I am surprised that PCS used to make a value body with engine braking in the electronic shift mode and apparently TCI was preparing a VB to do the same and now it seems that no one knows anything about it? I am not that knowledgeable about automatic transmissions and was hoping that the 6x would be the way to go for my car, but that was based TCIs advertisements, manuals, and techs before I bought it. The TCI 6x seems to perform well enough but the lack of Engine Braking is a real problem in a road car. Maybe I should have never switched to an automatic, but I thought I could have the best of two worlds. Before I give up and return it, is there anyone or a company out there that knows how to provide Engine Braking in the electronic shift mode?

[scottsdaletrans]

I have a lot of insight about the 6 spd 4l80e. Gm originally created a 6 spd 4l80e prototype in early to mid 1990’s. The engineer that built it left GM and took a job with PCS at some point. TCI had hired PCS to consult on an unrelated project and the engineer told TCI about the 6 spd 4l80e. I believe TCI contracted PCS to show them how to do it on the context TCI would be buying controls and wiring harnesses from PCS. TCI then went with computers and harnesses from a different vender. I believe PCS did sue TCI. The only reason PCS started selling the 6 spd valvebodies and computers was to stick it in TCI’s eye.