I asked this question late in another thread, and it got overlooked, so I'm starting fresh. My sister is most likely buying a 2003 Mercury Grand Marquis with 105k from another family member. It has a 4R70W transmission that has confirmed torque converter shudder. I know I need to do a fluid exchange (not a flush) and install a new filter. But people and trans shops are giving mixed advice. All agree on Lubegard additives. But it is split 50/50 on which one. Some say the standard LubeGard red, others say the LubeGard/Dr. Tranny Shudder Fixx. I am under the impression that both are good, but I need input. What are the real differences? Is one better than another? One preferred over the other in this case? Both? Can these two additives even be mixed? Help! Thanks in advance!
On a side note, it's kind ofsad funny that I 'must' consult BITOG before reaching conclusions regarding fluids.
On a side note, it's kind of