Our 2001 AUTOMATIC i30 slips out of gear usually when we are driving between 40 and 50 MPH. We lunge forward and pray that no one rearends us! It’s like we are stuck in first gear all of a sudden. (The gear shift is still showing that we are in D for drive!)
The only solution is pulling over to stop, turning off the engine, waiting 5 minutes, and restarting.
We took it to a transmission place for a few weeks and they couldn’t make it repeat the problem! Any one have an idea of what’s happening? Would getting a new transmission fix this?!?
I am not that conversant with the I30 automatic transmission so take my ideas with a grain of salt. Usually when a transmission drops into ‘limp home’ mode, the transmission computer has recognized a problem that it cannot adapt to and forces the transmission to go into a safe mode that still allows the car to be driven although with poor performance. The fact that turning the car off and restarting clears the problem is an indication that it might be a TCM problem. Usually a trouble code is set if this occurs. Ask the transmission place if they were able to scan the TCM and if any code came up. If so, post that code back.
It is unlikely that you need a new transmission. If this problem keeps occurring you might have the transmission shop replace the input and output speed sensors and any other sensor that would cause the TCM to go into ‘limp home’ mode. The dealer service department might be adviseable at this point.
Hope I have been able to help.