97 sl in limp -in mode?

we put our 97 sl500 in the garage for the winter when we got it out this spring it won't shift . it will go in reverse and will go in drive but it feels like it's in second it will run about forty but won't shift, any ideas? we changed the shifter as we've had a ml320 with the same problem and it was the shifter . but we tried that and no luck. thanks oh and yes we have checked for chewed wires.