Once you shift to reverse, which takes no more effort than any other gear, it'll roll backwards, but no matter how much gas you give it, it won't accelerate. It has a sealed transmission, so I can't check the transfluid level. I've lifted it in the air and checked for a level check plug but could only find a drain. There is no dipstick, nor leaks. There is a slight leak on the rear diff, but there's plenty of clean fluid in it. There are no present codes that pull up in the obd scanner. I think it may be a shift solenoid, but don't know how to go about testing it. Does anyone have any other suggestions what it may be? Or possibly how to test the calibration of the solenoid? Car only has 140,xxx miles. I'm at a loss here. Dealership wants to charge 200 for service, but I don't think that it needs a fluid exchange, that and it's never been serviced (due to being a no service needed trans.) I myself am an automotive technician of 5+ years, but neither myself or any coworkers can figure out what's going on.