Just rebuilt my 4r70e and now i am getting a P0731 code.
Short background, i had the trans rebuilt and it failed about 15k miles later the shop looked at it "under warranty" and two weeks later rebuilt it and said it wasn't their fault so they charged me again. I didn't really have a choice so I paid it and currently fighting that. Well 5 months later it failed again. I took it apart myself and found the rear bearing destroyed, clutches and steels where fine, all hard parts looked good. I did find out he installed the wrong sungear which was causing rubbing on the sunshell which i assume created heat and metal which destroyed my bearing.
All that to say i rebuilt the trans, checked seals and tolerances installed it correctly and when i take it on a test drive i am get a P0731 code. It reverses fine, once in drive it shifts thru the gears and doesn't hesitate or shudder. Once I stop and start again that is when i get the gear ratio code. Additionally, if i put it in D2 it will work, i only have 2nd gear but i do have engine braking but doesn't throw a code. When i put it in D1, i can feel it engage and it does move about an inch when i let off the brake but it won't move. It feels like there is a load on the engine but is binding somewhere. When i let the truck sit with the battery unplugged and start it up it feels like it starts in 1st but doesn't engage first after that.
I dropped the pan and changed out my shift solenoid and gaskets hoping that it would be an easy fix but no luck. I am really not wanting to pull the whole transmission if i can avoid it but will if that is what is needed. Does anyone have any insight with this at all?? I am desperate as this is my main mode of transportation.
Additional background, when it was rebuilt the first time, he did say he added a shift kit. I don't know if he did or what he added. I did add a sonnax line booster kit to my valve body. I noticed when i made this change that the upgraded booster was already in the VB
but it didn't have the spring i had with my kit. I made the change. I also switched out the 1-2 accumulator spring. I dont know, i am thinking i could have messed with something there. I just can't imagine something is installed incorrectly internally since everything else is working fine and was within specs.
Thank you for any help you can provide. Sorry for the long first post but i heard that this was the place to ask tech questions