Hello guys, I currently am having issues with my tranny rought shifting on my 300, I did a tranny fluid change (not flush) done like 750 miles ago and it seems to have made it better but I still get some rough shifting. My car has 169k miles on it and I bought it with 135k, ever since I had it the issue has been there. I decide to check my scanner into the tranny module and I find that the output shaft speed is giving me a "no available RPM" and it is in bright red. Could that be the reason why my transmission may be shifting weird?? Thanks for the help!!
As fas as I know these Mercedes-Benz/Chrysler 722.6 transmissions do not have an output speed sensor.
I'd assume that the output speed is a calculated value, I'd try driving it and looking at the data.
These don't even directly measure the input shaft speed, they calculate it by the (using N2's readings of the front sun gear and N3 readings of the front planetary carrier - sensors are on the same plate about 5 cm apart and both use the hall-effect to count little regularly spaced holes in the sun-gear assembly and the carrier assembly it's connected to) These sensors fail very frequently, and a lot of owners end up needing new conductor plates, but even then the TCM sets DTCs and most of the time goes into limp mode - it usually does not cause rough shifting...
These transmissions are very repair friendly - everything is accessible and easy to work on (and they have nice protections against people with poor mechanical skills)
If it get's worse test the solenoids, they do tend to get clogged from dirty ATF (if you don't replace it very 37.5k - 43.5k miles depending on the exact variant) - test the solenoids, or maybe just replace them and clean the valve body - on these old transmissions they're under $100 for the entire set.
At worst you might have to get someone to put a rebuild kit on it, or just get a good junkyard unit (but try finding one with a warranty)
