The engine probably shifts at a higher RPM to warm up faster. I know in many cars, overdrive is disabled until the engine reaches operating temperature. The squeak and metal noise may be motor mounts getting old and worn.
2005 Scion xB
Headunit: Kenwood eXcelon KDC-X996
Front stage: TruTechnology S44 (200x2@4Ω Bridged) / RE Audio RE6.5C 6.5" Components
Rear stage: Massive D800.4 / Pioneer GM-5400T / Pioneer TS-D1702R 6.75" Coax / 2x RE Audio REX6.5 6.5" Coax
Sub stage: 4x Sundown SAZ-1500D (0.5Ω each) / 4x RE Audio SX 15
Electrical: Mechman 270A / 2x DieHard Platinum Group 31 (Odyssey PC2150) / DieHard Platinum Group 35 (Odyssey PC1400) / 2x Custom 150Ah