Does A Turbo 400 Have Overdrive?

How many gears does a Turbo 400 have?

TH-400 transmissions are three-speed automatics, with a 2.48:1 first gear.

Reverse gear is 2.08:1 and third gear is an even 1 to 1.

Turbo 400s use three tail shaft lengths; the most preferred units for a GM swap would have the short 4-inch tail shaft..

Will a TH400 shift without vacuum?

Unless it has a manual valve body it won’t shift without vacuum until very high RPM’s. Besides the fact that when you disconect the vacumn line the line pressure goes to full which can wreak havock inside the transmission, I don’t think that it will shift into high gear.

Is a TH400 better than a TH350?

Automatic transmission fans will tell you that a TH400 is a stronger transmission, but the TH350 is shorter (meaning easier to adapt in smaller-bodied cars), and it saps a lot less horsepower from the engine to make it work. … These transmissions weigh about 125 pounds.

Can a 700R4 handle 500 hp?

Quote: The Street/Strip 700R4 is good for about 550 hp maximum, but with the HD input drum it is good for about 625 hp max. Add another $240.00 for the input drum. I give a one year warranty with all my transmissions & torque converters.

How much is a 400 Turbo transmission worth?

selling it as a good unit and with a “it will work” or your money back warrantee, it should be worth $150-200. There are many shops that sell a stock rebuilt TH400 for $600.

Where does the vacuum line go on a Turbo 400?

The vacuum line on my ’67 connects to the base of the carb, but below the throttle plates. It gets manifold vacuum that way. It is the original engine and carb, and is not modified.

Is a TH350 stronger than a 700R4?

While a vehicle with 4.11 gearing may scream down the highway with a a TH350, it’s going to keep the engine in the power band longer. The 700R4 goes from a 3.06 -> 1.62 1-2 shift, which is way more aggressive than the Turbo 350’s 2.74 -> 1.57. Simply put, the TH350 is going to keep the vehicle in the power band longer.

What’s the difference between Turbo 350 and Turbo 400 transmission?

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.

How much horsepower can a stock powerglide handle?

3,500 horsepowerWith all the available upgrades, both the Powerglide and the TH400 are capable of withstanding an incredible 3,500 horsepower.

How much vacuum does a th400 need?

Coan told me 13-14 at idle inches of vacuum is needed for a modulator to work properly.

How does a TH400 kickdown work?

Instead of a linkage or cable, the TH400 uses an electrical switch that is most often mounted on the carburetor. … This electrical input powers up a solenoid in the transmission that accomplishes the same results, with higher line pressure and a signal to downshift the transmission.

What’s better 700R4 or Turbo 400?

The TH400 is much stronger, but it doesn’t have overdrive and the first gear is only 2.48:1. The 700R4 has an overdrive gear (0.7:1), and a 3.06:1 first gear, but it’s not as strong. So it depends on what your using it for and how much power you have.

How much horsepower can a Turbo 400 transmission handle?

400-450 HPAbout 400-450 HP/TQ is the limit on the stock TH400. With ONE almost free modification and some minor valve body calibration changes, 800 HP on an otherwise stock TH400 is not a problem if it’s assembled well (good endplay, etc), and the 34 element sprag is a wise addition above 450 HP or any drag usage.

What vehicles came with a turbo 400?

Generally, here’s a list of cars that used the TH400 transmission:1965-1967, 327 V8 (Rambler/AMC)1968-1971, 350 V8 (Buick)1969-1972, 225 V6 (Buick)1972-1975, 232 I6 (AMC)1975-1979, 258 I6 (AMC)1972-1979, 304 V8 (AMC)1972-1979, 360 V8 (AMC)1974-1975, 401 V8 (AMC)More items…•

Does a Turbo 400 have a kickdown cable?

Did you know that GM’s Turbo 400 three-speed automatic transmission uses an electric switch instead of a cable or mechanical linkage to downshift a gear at wide open throttle?

How can I tell if I have a 400 Turbo transmission?

Look at the transmission pans on both transmission. Both transmission pans have 13 bolts, but they have a different shape. The TH-350 uses a square pan, with one corner cut off. The TH-400 uses an oblong-shaped pan with one side having a “hump” in the pan and one side is curved while the other two sides are straight.

What does TH400 stand for?

automatic shiftThe TH400 is an automatic shift, three-speed, longitudinally positioned transmission. It is widely regarded to be a supremely durable and legendary transmission. The TH400 is conservatively rated at 450 ft. lbs. of input torque.

What happens when a vacuum modulator goes bad?

The main symptom you will notice is poor engine performance. If the diaphragm of the vacuum modulator were to have a leak in it, you will have a leaky vacuum and your EGR system will shut off. If the vacuum leak is too severe, then you will notice less power in your engine as well as acceleration problems.