limp mode?

okay. so, i have the van listed above that runs fine, i mean great! then out of nowhere the A/C stopped blowing hard it would blow hard then not, then the battery drained overnight. not once but twice, the third time the battery drained was within an hour… the wial coming to a stop at a red light the vehicle kicked down into 2nd gear limp mode i mean you can reset it and it will shift through all the gears but when you slow down it will kick back to limp mode.. took it to the dealership they told me i needed a new transmission 7000 i know better i checked the fluid and it’s bright not burnt… after getting it home it stopped running i jumped the relays for the fuel pump and cranks right up… the codes say it’s syloNoyd two..please help