The one accumulator spring kit I know of is not a factory kit or aproved method. It is made by a very smart MB trans expert Mario Aristides from Independent Transmission in Miami. The kit probably costs more like a 100 but has maybe 50 different springs and some pretty good instructions. I have one and have used it with mixed success a couple times. Experience would help a lot here and Mario could probably make it sing "Dixie" using it.
I don't recommend it anymore as the whole affair is just a bandaid on the original ailment if the tranny has more than 150k.
Bosch Master, ASE Master, L1
33 years MB technician