Automatic Transmission Torque Converter problems of the 2003 Mazda Tribute

My 2003 Mazda Tribute just recently began losing power. Late last week I noticed it wasn't grabbing as it should shifting (automatic) between third and fourth gear. Took it took recommended repair show and they are indicating transmission rebuild is required. I just checked the fluid level last week and about two or three weeks prior and all was well there. Engine blew on same vehicle at 70k miles despite oil changes every 3000 miles. Repair shop estimate: $3500 for the following: filter, overdrive band, bushing kit, bearings, drive chain, torque converter, solenoid block, mlp switch, forward planetary gear, and fluid. I cannot believe a vehicle this age with less than 80,000 miles has lost an engine and transmission under normal wear and tear, when proper maintenance has been performed. Carmax did honor the warranty for the engine failure, but the extended warranty coverage only extends to 75k.

The contact owns a 2003 Mazda Tribute. While driving between 45-65 mph, the vehicle makes a loud vibrating sound as if the transmission was failing. The contact feels that the driveshaft will spit in half. The final assessment was that the torque converter needed to be replaced. The purchase date was unknown. The current mileage was 91,000 and failure mileage was 87,000.