Car threw a P0746 Code, at start all the gears are illuminated on the dash. My scanner says "Transmission Fluid Pressure Solenoid performance or Stuck off". Car is not moving in any gear once selected. I went ahead and jacked car level on jack stands and checked the fluid, it seems when I reach my finger into the fill plug it is sitting where my finger is. perhaps it is time to do the entire valve body/solenoids? Thanks ahead of time and I will be sure to purchase a ross tech vcds for this issue and may help diagnose other future issues.

 

Yup, sounds like a transmission solenoid failure. Hopefully not too difficult to fix if you’re a competent DIYer.

 

Yes, have ordered a new filter as well as the pan gasket and the solenoids from ZF (Rockauto) along with fluid.


Old transmission filter was from 2005! This fluid and filter was never changed.

Condition of the old fluid... Smells like burnt toast...

Car has recently hit 180,000 miles..

 

I am currently looking to also fix the occasional flare up in 5th-6th gear and hooting as well... I'm calling ZF Eriksson as well for the "Mechatronic Adapter Seal - 6HP26"

 

Hi.

Suggestion: first complete the basic fluid and filter change. You really want to change the fluid 2-3 x anyway to get most off the old fluid gone, so the first change gives you a chance to assess if there is any diffference before going on to more. See mention below of possible low fluid as an easy fix. You could also go one more step at first and pull the valve body but not yet disassemble to get solenoids out and back in--changing only that upper seal (more below).

The lack of any action/movemet in any gear that you report is concerning. I am thinking variously it could be all the way on the spectrum from just badly low on fluid (not uncommon on old ones, and a given if you had any leaks) to internal catastrophic. If you did not drain at least 4+ quarts/liters before you pulled the pan, and maybe 1-2 more total with the pan off, you were low on fluid. Not finding big metal bits in pan is a helpful indicator--clutch pieces, and other things--but could probably still be bad things like the oil (fluid) pump or drive.

Yes, could be solenoids too, but >10 years since I did mine so memory faded some.. Look at the solenoid table in the ZF documentation to see which solenoids act in which gear(s). Only if one is relevant for ALL gears--both ALL drive AND reverse--would that logically fit into a full failure like you report.

As far as the work for a solenoid swap, if you look at my old post and all the nitty gritty, the two big watch areas I recall are separating the Mechatronics module from the valve body, and being sure you disconnect and reconnect the linkage correctly. Even 10 years ago, the Mechatrronics plastic seemed very fragile when I did mine. But yes, the results were GREAT, and car is still on road another 80K plus miles later and no tranny issues. Take a lot of time, have a good work surface, etc.

And yes, my best sense of the hoot and 5-6 flare from the criss research I did with sinmilar era MBW V8s and similar (non AWD) version of ZF tranny is it is that upper seal. A badly breached seal could also mean no fluid pressure in the valve body, and then in turn no drive.

 

I just finished up cleaning up old valve body and reassembled with new solenoids just waiting for pan, filter, and gasket... Along with the proper ZF Valve body seal on the way as well should be done before Christmas. Pics below includes old valve body seal

Clean valve body + new solenoids from ZF

Old Valve body seal + reminder to take old filter orange seal out

 

I have reinstalled the valve body with new solenoids, and bridge seal. Following the fill procedure the car took about 7 or so quarts of fluid, Car has no error codes and drives perfect now with fresh fluid, filter, solenoids, and valve body seal. Successfully doing the adaptation drive, it shifts great. Will update if anything occurs. Thank you Dvsdave and MP4.2.

 

Great job, and glad it worked out.