I have a 1997 SL500 with around 102k on it. Not very often but sometimes when i just start the car and start driving, the very first shift into 2nd gear is hard (shifts with a moderate kick). The car shifts perfectly after that and i can stop at a stoplight and drive out with no problems. Again, this a very first shift into second gear. I do warm up the car before driving. The tranny fluid has been checked and at the right level.
Is my tranny going bad? Ive never herad of an older SL with a bad tranny.
If it were me, I would check the regulator spring (I think that what it's called). The spring is on the side of the valve body. You need to drain the fluid, remove the pan and the valve body and check the spring. The spring only costs less than $3 but you might need new transmission fluid, filter, gasket etc.
In fact, my CL55 has similar issue and I am going to do that in the coming summer.