As was eluded to early in this thread, what’s important is to get old fluid out and new fluid in to assess the shudder after new fluid. Hopefully, an improvement is felt so the OP can continue with further changing over the transmission fluid. There are people who help from direct experience with the XC90 TF-80SC transmission then there are those who don’t. The different methods have been discussed ad nauseum and not one person owns fluid change procedures.
With any changeover with new fluid, let’s hope the shudder is as simple as replacing old transmission fluid for the OP.
With any changeover with new fluid, let’s hope the shudder is as simple as replacing old transmission fluid for the OP.