Trans does not seem to slip, but shifts hard and seems to upshift early and downshift late. Driveshaft carrier bearing is going bad is it difficult to replace.

Transmission modulator has vacuum to it ???
check brake booster line vacuum connector is not clogged up and check all vacuum lines
rubber connectors for cracked.
hope this help.

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MB STARS Master Guild Technician,12 years MB tech
5 years independent shop owner

Check the rubber cap on the modulator also.

David