I need help. A couple a winters ago it got very cold here and My transmission wouldnt engage first thing 4am. It happened only once and then again once this last summer 1 mile down the road at a stoplight. I finally got around to a fluid and filter change the middle of last week. 50 miles after that now and until tonight it would not engage without a lot of fenagaling. Like shifting through the gears slowly. I was getting a quad driver 4 code 670 error. I added a half bottle of lucas. I also found that pulling the vacuum hose off the transmission modulator let the car shift normaly but with a harsh hard clunk. I read here that changing trans fluid after way too late on an old trans clears the system of grit needed to provide better connections. Thats its or the pump like Will suggested. So a $1350 new trans or $13.50 modulator? a new modded trans would be choice

Please don't double post. Continue using your current transmission topic.