1999 Legacy GT transmission trouble shooting

[99legacyGT 0]

To start off, I don't expect you guys to automatically know whats wrong with my car. I'm partially looking for advice with this thread, but also using it as a journal of sorts to keep track of what I go through with this problem.

Anyway, the problem: 

I bought this car about four months ago for less than two-thousand USD. It's my first car, and I always wanted a wagon, so this was perfect. For about the first month, everything ran smooth. Then, the spark plugs started acting up. Replaced those, and everything was peachy again. Now, about a month after changing the spark plugs, I'm having a problem that's hard to describe. 

The car will be fine and the transmission will shift as intended, and then all of the sudden, a check engine light comes on and the transmission (I assume) starts to get clunky in a way. It's happened four times now. The first time, I was in a drive through, and the CEL came on. I pulled into the parking lot to inspect things, and could find nothing immediately obvious wrong with the car. It drove as intended for about two miles, and then as I rounded a corner from a stop light, second gear started doing the clunky thing, and wouldn't accelerate past 20 mph. I pulled over, contemplated what I should do, but knew I could do nothing sitting on the side of the road, so I pulled off and headed home as I was only 5 minutes away. It didn't happen again the rest of the way. I drove the car again that night for about ten miles and nothing went wrong, no CEL. 

A couple days later, I was coming back home from a relatives house, about a 30 minute trip, very heavy traffic, and as I got close to my house, the car didn't want to accelerate again, and was "clunky". Thats the only way I can describe it. This time, it felt like it was every gear doing it. I parked it, shut it off and then turned it back on, and it kept doing it. I got home, and then shut it off and let it sit for about two hours and decided to test it again. It operated as intended. 

Yesterday, I made the same trip, but went out of my way to avoid traffic. As I neared my house, the CEL popped on, but nothing notable with the transmission happened.

As of this post, I just ran the car from a cold start to operating temperature to check the transmission fluid, and to me, it seemed low. I filled it to approximately the full mark for a hot temperatures and ran it again to double check the level.

I scoured the internet since the first hiccup, and came across a thread that pointed to possibly a grounding issue with the transmission. It half-way described my problem, but my grounds seem okay, even after unbolting and rebolting them, but I won't rule it out, For now, I'm going to assume (and pray) that the low dexon level was my problem. I'll post again if I have more issues. 

Feel free to reply with advice, it's all appreciated

 

[987687 316]

Does the AT TEMP light ever flash? If not, it probably isn't a transmission issue.

It sounds like the throttle position sensor (TPS) is intermittent. If that fails, it'll cause funny shifting. When it died on my car, it caused really early shifting, slammed through the gears and wouldn't downshift.

 

However, unless you figure out what code the CEL is on for, all anyone can do is guess. You need to have the code read, it'll point you in the right direction.

[Rooster2 256]

Sounds more like an engine problem, not a tranny issue. Have the code pulled that is presenting itself as a CEL. Once you have the code, you can identify what the engine is trying to tell you what the problem is. Many auto parts stores will pull the code, at no cost, and tell you the code reading. Autozone will do this, Advance Auto Parts has stopped pulling code.

[99legacyGT 0]

As an update, since topping off the transmission oil, I've had no trouble with my transmission

maybe i've lucked out. I hope so

until someone goes wrong, i have nothing else to say. Anyone else having this issue, I guess you should make sure your transmission fluid isn't low. On the 1999 legacy gt, or at least on my car, it's hard to get a good read on the level. The stick with slide against the tube it runs down and smear the fluid around on the dipstick. 

Anyway, thanks for replies, i'll get the code pulled the next time I get one.

[99legacyGT 0]

Does the AT TEMP light ever flash? If not, it probably isn't a transmission issue.

 

The only time i get the at oil temp light is when i start the car, or when i unplug the MAF sensor. When I unplug the MAF, the at oil temp light will flash 

[Fairtax4me 1439]

When the cel comes on the ECM stores a code. Even if the light goes out the code is still stored for a certain time frame. Take the cat to an auto parts store and ask them to scan it for codes. There are also plenty of inexpensive code readers on the market you can buy so you can check the codes yourself anytime the light comes on.

 

Post the code numbers here and we can help diagnose what's going on. It's an intermittent problem at this point, but it will only get worse. You should take certain steps now to try to determine what's actually going on, rather than waiting until its stuck in limp mode and you're 100 miles from home.