2006 ML350 92k miles

Yesterday I lost power on the freeway. Vehicle was towed, by insurance co. per our emergency road service policy to the nearest reputable dealer. Leaking found around torque converter. Pulled transmission today and determined the transmission should be rebuilt because there was a problem with the bushing and repair could not be guaranteed. I’m not sure whether this is a valid diagnosis. Of course to rebuild the transmission iwould cost half the value of the vehicle. I am having a dilemma and need advice.