I know this subject has been discussed before, but does anyone have "actual experience" with replacing the 6x valve body with a standard 4 speed valve body and what were the results? I have posted on other threads about my issues with the 6x and the lack of engine braking and got a lot of good technical responses and was told that I "should" be able to run a standard valve body in it.. TCI's technical staff suggested running the 6x as a 4 speed with a ratchet shifter rather than my bump shifter to get some engine braking. I tried programing the TCU to run in the 4L80e program mode, but had no overdrive gear in that mode, and TCI said something might be wrong with my valve body, because I should have overdrive in that mode. They said I can put a standard valve body in the 6X, but that would void my warrantee. The 6x has other issues which I have now also read about like shifting flairs and very hard 3rd planetary gearshift under WOT, so I am trying to see if I can make this transmission into a 4 speed and use the Sonnax VB with Smart-Tech overrun clutch circuit for stronger engine braking and better shifting characteristics. I know it won't have the same gearing as a normal 4L80e, but I believe most of the other issues would be eliminated with a good 4 speed VB, but need to know it will work for sure! Obviously, I am trying to avoid pulling the 6x out and starting over with a new transmission.



I

 

Send me the 6x
I'll send you a 4 speed that works



haha

Jokes aside, the case side of things is not changed. Which means when you pull that 6x valve body off, you're left with a "normal" 4l80e

You will need a valve body, separator plate, and new gaskets.
I'd recommend just getting a while new internal wiring harness also.
You may also need to get new checkballs

 

Ha-Ha, I wish, but I think I am getting too old to pull out that boat anchor and put another one in. It's a tight fit in a 71 Camaro RS. Yes on the harness as I don't want that extra solenoid wire flopping around in the pan. Yes on the check *****, as I read somewhere that they leave the 3rd gear check ball out, which causes a very hard shift. On mine, it feels like the driveshaft is going to get torn out at WOT.

However, I am dealing with another issue right now; as they sent me a new TCU in Feb because of the lack of OD in 4l80e program mode and of course, it didn't change anything. The OD works fine in 6x mode, but not when programmed as a 4L80e So it turns out that the new TCU has a chip failure of some kind according to TCI, and my transmission locks into first gear once it's fully warm. I had even replaced the speed sensor before TCI said they had a bad batch of TCUs. Now I continue to wait for a new TCU because there is a chip shortage worldwide, and TCI hasn't been able to ship the new EZ-TCUs.