The transmission on my hyundai has been slipping on me when cold. I replaced what I could of the fluid but still mixed with the old stuff, used SP-III. This made the problem worse. It later completely wouldnt engage in gear until the engine was running for a few minutes. Now first gear doesn‘t engage at all. Reverse works fine. Someone told me that the torque converter is probably completely clogged or the filter because it does try to engage. Someone else told me that the transmission is shot. Does anyone have experience with these transmissions that could agree or not agree with flushing the system?
It seems like the transmission forward band is slipping. Flushing or replacing fluid will not help. You will have to overhaul or replace the transmission, period. the reason why the problem gets worse after fluid replacement is that the dirty fluid actually helps to seal minor spaces in the clutches and bands when new fluid circulates. It will pick up deposits and remove dirt sealing clutches and bands. Most trans shops dont reccomend replacing trans fluid on vehicles over 120K miles that haven had regular trans fluid maitenance for that exact reason.
Flushing your transmission is considered preventative maintenance. That is, you do it every 30k miles and it should extend the life of your transmission. If you already HAVE a problem with your transmission, not only with a flush not help you, it will generally make it worse. If you want to understand why I can elaborate, but I think that is beyond the scope of this question. Early Hyundai cars have notoriously bad transmissions. A transmission rebuild will probably cost more than a 1999 Hyundai is worth (no offense). I suggest you start shopping around for a used transmission or a new car.
I would suggest that you get a car alarm.
