My super V8 had a full transmission overhaul by a very reputable auto transmission repair garage. After the overhaul they have reset the adaptations and went through the adaptation procedure in SDD clutch by clutch. Everything was fine, except the adaptation of the clutch E. SDD says that adaptation is successful, but the pressure is much higher (450 mbar) vs around 100 mbar for the other clutches. The final result is that the 3->4 shift is hard. Before the overhaul the same shift wasn't hard, but a short "whining" sound was heard. They tried clearing and readapting multiple times. They inspected the transmission very carefully. They tried with a whole different transmission (again a 6hp26, but from a different brand, I think AUDI). They used the TCM from my transmission on the Audi one, because the Audi TCM (obviously) won't connect to the SDD. In all cases the same happened on adapting the clutch E, high pressure and hard shift into 4th, even with the Audi transmission. They say the only thing that's left is a problem with the TCM, but they can't source a spare Jag TCM to try it. I found a Jag transmission from an s-type diesel 2.7D at an affordable price which I can buy and get the TCM from, but they are concerned there's a risk that the diesel TCM will not work with my S/C V8. I expect the TCM would be the same, just with different programming, which one should be able to fix by configuring it as a new module in SDD, but that's just a wild guess.

So I have two questions

1. Does anyone know a solution for the hard 3->4 shift
2. Did anyone successfully swapped TCM from a diesel transmission to a petrol one

Help would be greatly appreciated.

 

Have you tried clearing the adaptations and simply driving the car around and letting the car learn without the step by step adaptation guide? Shifts must be below 2000 rpm for the first few miles. Have you updated the TCM to the latest firmware? perhaps a re-flash may be in order. The adaptations usually smooth out over time as well. How long has it been like this?
I have 3-4 shift issues on my current transmission, caused by a pressure loss in one of the solenoids for the E clutch. This leads to the dreaded squawk noise and E clutch slipping

Good luck on solving your issue I am keen to see what solves it.

 

If you contact ZF in Germany with all the details they do provide advice I believe.