I bought my '98 Forester about 3 years ago w/ about 75,000 miles on it and it worked great until about a month ago when it started overheating. It turned out that the head gasket blew, so long story short and $3000 later, I have a new radiator, thermostat, head gasket set, cam seals, spark plugs & seals, valve cover gaskets, etc. I had the timing belt replaced last year so the mechanic said he only had to rebuild the top of the engine rather than the whole thing. I picked it up from the shop on Thursday and it seemed to be shifting a little rough, but it wasn’t overheating. On Friday the check engine light came on and I took it back to the shop. The mechanic put the scanner on it and it was coming up as the Oxygen sensor. He said that might have been caused by the coolant that spilled when the head blew, and said it should burn out eventually so not to worry about it. He said if the light came on again for the same reason, he would replace the Oxygen sensor (the light hasn’t come on again). He also checked the transmission fluid level which was fine. Yesterday I noticed the shifting was becoming increasingly worse - it seems the car can’t decide btw 1st & 2nd and 3 & 4th gears; meanwhile the car is up to 4000 RPM @ 40 mph, and using a TON of gas. Then, the AT Oil Temp light started flashing. We looked at the manual which states that when flashing, this light indicates that the transmission controller is not working properly (no kidding). I feel lucky to have made it home last night, the car was driving so poorly. Any thoughts or advice??? I am not a mechanic and feel totally in the dark about all of this. Is it a coincidence that I just had a bunch of work done on the car (and the engine was completely removed in order for this work to be done), and now a whole slew of new problems surface?
I would suspect that this problem is caused by something wrong with the transmission fluid but can’t that for sure. You may want to have a specialist look it over.
He checked the transmission fluid level but did he check the fluid condition?
Also, did he check the differential gear oil, which has its own dipstick?
If the differential oil is mistakenly drained (another thread is present on this issue and its easy to do) it’s possible the ring/pinion gear is binding which can cause the ATF to overheat.
I would advise checking the fluid levels yourself just to make sure. Note the drivers side dipstick (ATF) is easy to see.
The passenger side (diff. oil) is not so easy. Here’s what the trans looks like and note the tiny bit of yellow on the 2nd pic from the bottom is the diff. oil dipstick.
This one gets overlooked, a lot.
If the 2 fluids are fine both as to quantity and condition then you should get the vehicle scanned at a transmission shop.
There’s a few other things possible here but not enough info is available to go much deeper into this, although one wonders if the trans fluid could be contaminated by engine coolant due to a leaking trans fluid cooler.
ok4450 is absolutely right about the transmission and differential dipsticks being mistaken and missed a lot. I don’t know what’s causing your problem, but the guys at http://www.ultimatesubaru.org/forum/ should have an answer for you if it’s not a fluid issue.
Thank you all for your replies. This is going to sound crazy, but my car seems to have healed itself. As per the manual’s suggestion, we drove it and made sure the car went into every single gear - even manually used 2nd and 3rd, and the problem went away. The night no longer flashes and it shifts correctly. My husband thought maybe the AT fluid wasn’t getting to every gear, and said he’d also heard that a car’s computers are capable of re-teaching themselves how to function properly - not sure about that but I don’t have an explanation for this apparent miracle. Has anyone ever had a similar experience?
Glad to hear things are looking up. PLEASE check the transmission fluid level. Read the owner’s manual if you don’t know how to do this (it’s not as simple as checking the engine oil). If the fluid level is OK, and the transmission continues to operate normally, you’re probably good to go, and have nothing to worry about.
The ECM (computer) controls the transmission operation through a set of electrical solenoids in the transmission. It’s possible this problem could be nothing more than a hiccup and will not occur again. Faulty wire connector, sticking solenoid, etc. is anybody’s guess.
A scan at the transmission shop may pull something up or you could choose to leave it alone for the time being until when or if the problem surfaces again.