These transmissions mate a three-element turbine torque converter to a Simpson planetary geartrain, providing three forward speeds plus reverse. The Turbo-Hydramatic or Turbo Hydra-Matic (THM) …

Comprehensive guide to the GM TH400 automatic transmission — specifications, identification, history, and adaptability for Jeep conversions.

4 days ago · Despite the higher number in its name, the TH400 came out in 1964, five years before the TH350. The TH400 is more heavy-duty, too, featuring stronger components like a 32-spline output …

The TH400 is an aluminum cased three speed automatic transmission that was produced by GM. It was introduced for the 1965 model year and made its debut in Cadillacs, and is respected for its durability …

Sep 20, 2025 · Developed by General Motors (GM), the TH400 was introduced in 1964. It wasn’t just an upgrade; it was a completely new design that aimed for greater strength, smoother shifting, and …

The TH400 is highly regarded for its strength and reliability, even in heavy duty applications. Its central design would become the foundation of late model overdrive transmissions used in GMC and …

Sep 11, 2025 · The TH350 and TH400 are GM’s most legendary transmissions. Learn the differences in strength, weight, performance, and applications.

The TH400 is a venerable transmission that has its roots in mid-century automotive tradition but has since been modified for modern use. It is an automatic shift, positioned longitudinally behind the …

Jan 20, 2026 · Discover how the TH400 transmission evolved from muscle cars to modern performance. Learn about key upgrades, durability, and why it's still a top choice today.

4 days ago · Meta description: Uncover the key differences between TH350 and TH400 transmissions to make informed decisions for your vehicle. Learn about specs, performance, and real-world applications.