Ok. My girlfriend just bought a 2000 tib. The check engine light was going on and off. She said it was acting funny, so I drove it. It had no 1st gear or over-drive(auto tranny). I took it to Auto Zone and they read the codes.

P0734=Fourth gear incorrect ratio
P0750=Shift control solenoid valve A
P1624=Low cooling fan relay circuit fault

The fan was just a relay change...

Do you guys think the trans is roast or do I need to change the TCM. I've found one that a guy would get rid of, but I don't know how much he wants for it. Any help would be appreciated. Sorry for the long post.

long post? lol... stick around a while.

I'm not familiar with those codes. Not aware of anyone who's had them. Someone here might have a spare TCM since several of us have swapped the tranny. How many miles are on the automatic? Both of mine last 60-62,000 miles before they crapped out, but both crapped 3rd.

Incorrect ratio means the input and output speeds are wrong. That happens when the clutch packs slip. That happens when someone fails to use the proper fluid when the transmission is serviced. That happens when you go to jiffy lube.

Shift control solenoid is also internal to the transmission.

If you don't know when the transmission was last serviced, or what fluid was used, it is very possible you need a new/rebuilt one. Car-part.com may be your friend there. The transmissions and TCMs changed through the years and you need to be sure to get the proper-year part. If you want to toss slightly less money at it in a potentially futile effort, get some ATF from the DEALERSHIP and get a filter as well. Change the fluid and filter, preferably run a flush. If you're not a big DIY'er or don't want to pay the money for the (expensive) Hyundai fluid twice, this is when you take your car to the dealership to have their tech check it out. Report back with what they find.

The car has 145,000 miles on it. I'm willing to do a tranny swap, Just didn't want to do it if it didn't need to be done. I found a TCM for $20. I'm gonna go ahead and get it and do a tranny flush. I'll find some OEM tranny fluid too. I'll keep everyone updated. thanks.

So we called the guy that sold us the car last week. He said he had no idea that it was acting up. He told us to take it to a mechanic and he would pay for the rebuild. So I'm happy.

sounds like a good deal. 99% of people after selling you a car will leave you high and dry.

Make sure you get that in writing or something, in case he backs out when he sees the bill. Eyecrazy.gif

I have it in writing and he went to the shop with us. The guy at the shop thinks its the selenoid. he said he's gonna change it first. I guess you have to go through the dealership to get them. I hope that's all that's wrong with it but i'm not gonna hold my breath.