L322 ZF8HP70 gearbox problem

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I don't know if it's related but SDD is still not happy, complains the deployable side step isn't running.. well it's never had one!!
I also read somewhere about invalid ccf but can't remember where i saw that. It didn't say what was invalid
 
The speed sensor for the transmission output in rpm - not the wheel speed sensors or the composite road speed on CAN, an actual rpm value from the TCM, there is also a turbine speed sensor (Transmission input speed) also in the TCM, there are not that many PID's in the TCM so you should be able to identify them - you're looking for the readings to be plausible - i.e. output is >0rpm when the vehicle is being driven and smoothly increases/decreases, same goes for turbine speed but you don't need to be moving to read that one. I can't remember the correlation to engine rpm (it may be 1:1) but it'd be worth having that displayed along with the turbine speed to check for any anomalies in speed variation - also check in 'S'.
 
I didn't see a live data selection called output speed sensor but saw a few others.
Transmission output shaft speed was interesting, it was at zero apart from a spike when starting and a spike when stopping.
There was transfer box motion sensor voltage which went from low to high, the switch happened before i came to a stop
 
8hp has a reputation for issues in the valvebody usually pressure leaks that can cause the trans to act erratically.

The priming valve in the valvebody losing fluid pressure is a favourite that can cause it to shift poorly.
 
I didn't see a live data selection called output speed sensor but saw a few others.
Transmission output shaft speed was interesting, it was at zero apart from a spike when starting and a spike when stopping.
There was transfer box motion sensor voltage which went from low to high, the switch happened before i came to a stop
That does not sound right to me.
 
8hp has a reputation for issues in the valvebody usually pressure leaks that can cause the trans to act erratically.

The priming valve in the valvebody losing fluid pressure is a favourite that can cause it to shift poorly.
In the higher gears, with high throttle inputs it seems fine, there would be greater leakage and bigger symptoms?
 
Have you had the adaptions reset?
Don't do that! The only time that should be done is if a software change requires it or solenoids have been replaced, doing so on a 'box that has had no work done can lead to some pretty bad shifts, some 'boxes never achieve their previously 'acceptable but could be better' shift behaviour.
 
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