Automatic Transmission won't upshift
 

My transmission feels like it only has 2nd gear, can't even trick it into overdrive with the button on/off, my car supposedly has the same transmission as the Mazda Protege although it is a 96 Probe GT, automatic with 107K, any ideas on what is MOST probable here?

How often did you service your transmission? Automatic transmissions require service every 30k, failure to do so will cause the fuild to break down and it will eventally burn up your transmission, remember heat is the number one killer of an automatic transmission. You could also have a low fuild level, if I where you I would go ahead and service it, what do you have to lose.

Low oil could prevent an auto transmission from hitting high gear, but if you're always in second gear, then you're in 'limp mode'. The '96 Probe uses 2 different auto transmissions -- depends on 4 cyl. vs 6 cyl. Both are electronically controlled. They use solenoid relays to shift gears. When there is no power to any solenoid, you're in second gear by default. This fail-safe mode allows you to limp to a shop.

Your problem is almost certainly electrical. It could be loss of power, bad control module or bad solenoid(s). Get it to a shop to get it checked out. You don't want to drive it too long in limp mode or you could do physical damage by overheating the transmission.

30K?? What? It's 50K.

VB,

It all depends on a couple of factors, I live in florida so with the hot weather and my highway driving my fuild tends to break down and discolor faster than say someone who doesn't drive very often. Heat is the number one killer of transmission, my brother in law works for a transmission company and also builds transmissions for a living so he told me if you service it every 30k you will get the maxium life out of your transmission. Where did you get the 50k service interval, I looked in my owners manual under owner maintenance schedule and it states the fluid level needs to be checked at least twice a year, every Spring and Fall. Thats all it lists.

Vince

I got it from my service manual. Lol. But then again, I'm driving in NE conditions.

um... yea, the oil needs to be changed. But personally, it might be the filter in the tranny. maybe it could also be the ecu. i know it sounds stupid but first reset the ecu. Then check if the wires that connect to the tranny to the ecu if they are broken or not. Sometimes rodents chew through the wires. If not flush the tranny. And if that doesnt work, check the filter. You are goign to have to drop the pan for that. Good luck

Updated diagnosis
 

You were the most correct of the posts, the Transmission shop says there is a knock sensor code which is putting it in limp mode and here we go at $85 an hour as they wander through the electrical maze.

If it is an engine malfunction causing limp mode on your vehicle, then you don't need to be at a transmission shop. Does clearing the code cause your transmission to shift properly?

if its a knock sensor code, are you knocking? And if you do clear it, does it come back? If it does you have to fix the reason why you are knocking. There is reasons why they have "limp mode" Dont blow the engine haha