I will start from the beginning of my journey to hell and hopefully back. I took thetruck into a local garage to have the tranny flushed as I do not know what was in it prior and have AMSOIL synthetic ATF and spin filter replaced(to which they threw out the donut magnet with the old filter) installed. First trip out to work climbing a hill, thought it should of shifted out of fifth so I gave it a touch more throttle and when it shifted down(not smooth) it revved up to around +/-3000RPM and got a MIL. I pulled over and had only P,N,4th gear. I reset the codes and when I arrived home pulled the stick and found it a litre low, good color and no stink. Next day same place, same codes, same action. Got home and removed the 50HP HypertechIII tune back to factory settings. Next day..............you know. Checked the fluid again, all good. Took it back to the garage that did the flush, they checked codes and disconnected the battery for 10-15 mins, took it out for a test drive and said it looks good. I headed for hell hill and ..............you know, back to the local garage and they kept the truck for a whole day doing tests via scanner ect. Went to pick it up and was told to go to a tranny shop.

I decided to check this out on my own and following the service manual picked up"A" solenoid and dropped the valve body, cleaned it and installed "A" solenoid which would open up a little more than the original. (could not see through the side ports when old one was actuated, but can on the new one installed) Will be installing it today or tomorrow. Hopefully this solves the issue, as finances are limited and $3800.00 if I R&R or $5000.00 if taken in. Help

Anyone else have a similer problem with this series 1000 Allison?