FWIW, there are stories of normal running 722.6 trannies with a history of Mercedes spec 236.10, and then slipping after a fluid change with the newer spec Mercedes 236.14 fluid. Mercedes sez baloney, car should be fine with 236.14. Fluid 236.10 seems harder to find but I recently saw some at NAPA and they said it is readily available. IIRC it was Febi or some other German brand name. It is also possible that the tranny will adapt to the new fluid and run fine after awhile.