Not sure if your problem is the same. On mine the pass seatback would tilt forward but the seat stopped sliding. I fixed it yesterday as follows:
There is a cable that runs from the bottom of the sliding mechanism up the left side (if you are sitting in the seat) hinge into the seatback. The cable runs about 6 inches into the seatback where it is anchored to a steel plate (NOT up to the hand release) which supports the seatback. The cable snapped at that point. When the backrest tilts forward the cable tightens and pulls a "release" mechanism on the bottom of the sliding tracks. Fortunately the seat cover is velcroed & zippered together at this point making exposure possible (of coarse remove seat from car). Unfortunately it does not appear that the cable mechanism is replaceable by itself. I was able to drill a hole about 1 inch below the original mounting point and mount a screw there. The screw holds an electrical connector which I crimped onto the remaining cable. Sorry, did not think to take photos before reassembling. May not last long, will try being gentle with the mechanism.
On mine with cloth upholstery, the back of the seat cover has a big zipper on the back (the ends are tucked into the bottm corners) that exposes some of the insides, did not help me much but if your problem is with the release handle this might help.