Chevy Turbo 400 Transmission For Sale Craigslist (2024)

FAQs

What is the rating of the Turbo 400 transmission? ›

The TH400 is conservatively rated at 450 ft. lbs. of input torque.

TH400 History, Facts, and Figures

TH400's from 1965-1967 also featured a variable pitch stator which helped the torque converters characters and can be seen by the two-prong plug on the case.

The TH400 or Turbo 400 is a good transmission that was used in several cars years ago. This popular transmission was found in GM's cars, as well as, Rolls-Royces, Jeeps, Jaguars, Ferraris, etc.

TH 400 transmission tags have the trans code number stenciled and stamped on the tag, the last two digits of the year, and then the julian date of the trans build is often stamped in the center of the tag. At the bottom of tag, the last series of numbers is the sequence number of that particular transmission.

They are, for the most part, interchangeable on the same vehicles; however, you would normally find the TH400 in larger engine applications because they are able to function more reliably at higher engine rpms.

Is there a big difference between a Turbo 350 and Turbo 400 – and which one do I want? They are completely different transmissions. The Turbo 400 is larger, longer, and heavier than the Turbo 350 and was designed to live behind higher-torque applications such as big-blocks.

edit: okay, AA sez the 350 is 21.5", 700r is 23.375", 4l60e is 21.875", and 400 is 24.25".

Turbo 400 With Trans Brake

This transmission is available in 2-speed, 3-speed and 3-speed with 2nd-gear leaver. The 2nd-gear leaver option is something that can give you the best of both worlds.

The 4L80E is just a longer, heavier, overdrive version of the TH-400. It uses the same first three gear ratios but adds a 0.75:1 overdrive. This means that with a 3.55:1 rear gear, the overdrive drops the effective rear gear ratio to 2.66:1. This makes the first question more about torque converter selection.

Is a Turbo 400 hard to rebuild? ›

Rebuilding a transmission, such as the TH400, is not relatively as easy as changing your car filter or making an oil change. It is a challenge that will take a good mechanic almost all weekend.

Nick Johnson from Gear Vendors talks about how an overdrive unit can help a car equipped with a TH400 transmission. “This overdrive unit can handle upwards of 4,000 horsepower and is easy to install.

There's a cable that may be connected to the transmission's side and next to the location of the shifter linkage. In this case, you are to ascertain if the cable is connected to the engine. The cable is a kick-down cable and the TH350 has this cable whereas the TH400 does not have this feature.

Instead of a linkage or cable, the TH400 uses an electrical switch that is most often mounted on the carburetor. The 12-volt connection is a single spade connector just above the oil pan rail on the driver's side about halfway back–at least that's where it is on my TH400.

They are completely different transmissions. The Turbo 400 is larger, longer, and heavier than the Turbo 350 and was designed to live behind higher-torque applications such as big-blocks. That doesn't mean the Turbo 350 is weak in comparison.

Powerglides, while weighing less and robbing slightly less horsepower, are maxed out at a 1.62 low gear, making them less forgiving than a two-speed Turbo 400. Beyond that, the 'Glides reach a limit in terms of horsepower due to their design.

If you have a TH400 (or any other automatic with a 1:1 final drive ratio), 3.08 rear end, a stock engine (which poops out at 5500 rpm), 27-inch tall stock tires and 5% converter slip, the max speed you can theoretically achieve is 136 mph.