Mazda 323 Lantis (2000) automatic transmission, shows flashing HOLD light during drive, the car feels jumpy/shaky when shifting from Park to Reverse to Drive.
When pressing the gas during complete standstill, getting up to 10-20 KM/h takes much more time and "effort" than before this issue first appeared (a couple weeks ago). Also, it seems I can't get past 3rd gear.
A mechanic working at a Mazda-licensed repair shop (not exactly a "dealership") said diagnostics showed error P0763 which points to a faulty Solenoid C. Mechanic suggested replacing the transmission for a used one (cheaper than refurbished), said that replacing the solenoid might fix the issue but also may not. The issue with a used transmission is that it too may give up in under a year, not sure what shape it's in.
Replacing the solenoid would cost me $400, replacing the transmission for a used one would cost $900 (parts and labor). Didn't ask for a quote regarding a refurbished transmission, but according to the mechanic it could be over twice the cost of a used one. At that point, it would probably be smarter (financially) to sell the car. Regarding the second opinion, most licensed repair shops take around $50-$100 just to take a look - not sure if that's normal or above average.
The transmission hadn't had any issues before this issue arose.
Should I be taking my chances with replacing just the solenoid, or go for replacing the whole transmission?
EDIT March 2, 2017: I ended up replacing the transmission for a used one about 3 weeks ago. So far it works fine, maybe not 100% like the previous transmission, but good enough. I just hope it will continue working. Unfortunately, since I didn't end up going for the switch-solenoid route, I can't really know if that would have fixed the issues I was having. Thanks for everyone's input and advice. I will update this post if the transmission ends up dying.
EDIT August 2017: Still working, knock on wood
EDIT February 2018: Unfortunately the replacement transmission is showing signs of defeat, starting to struggle regularly. Will probably hold up for a while longer, maybe even more with just these hiccups now and the. But hey, at least it held in there for a year.