TH400 Master Rebuild Kit 1964, new and ready to install. Fits the TH400. Ships fast from the USA.
The Turbo Hydra-Matic 400 first went into 1964 Buick and Cadillac cars before Chevrolet and Oldsmobile picked it up for 1965, so early owners restoring a Wildcat, Riviera, Electra or Cadillac are often the ones searching for a complete kit. This Level 2 master rebuild kit is the fuller of our TH400 kits: on top of the clutches and soft parts, it adds the front band, the pump and extension housing bushings, a new filter and a new vacuum modulator. If your early 400 slips on the 2-3 shift, takes a long time to engage when cold, or has burnt fluid and lining in the pan, this is the box for a full overhaul.
The rear band is not included, so plan to inspect it and reuse it only if the lining is even and not glazed.
A TH400 shifts with hydraulics alone. Engine vacuum acting on the modulator sets line pressure, the governor tracks road speed, and the valve body uses those two signals to apply the forward clutch, direct clutch, intermediate clutch and two bands. Every one of those apply circuits depends on rubber and Teflon seals holding pressure and on clutch packs that still have lining. After decades of heat cycles the seals harden and the frictions thin out, which is why one kit that replaces all of them at once does more than any single part.
Pull the vacuum line off the modulator: fluid in the line means a ruptured diaphragm, which this kit replaces anyway. Check the fluid level and the linkage, then run a line pressure test. Our TH400 common problems guide walks through the usual failure patterns, and the pump failure guide explains when the pump itself needs replacing rather than just a new bushing.
We list this kit under 1964 because it covers the earliest Turbo 400 cars, but be aware the kit maker rates it for THM400 units from 1965 on. Most TH400 seals and clutches carried over from the first year, yet we have not verified every 1964-only hard part against this kit, so send us your year, vehicle, VIN and the transmission ID plate number before ordering for a 1964 car and we will confirm it. Variable pitch stator cars from 1965 to 1967 are identified by the two-prong plug on the case. If you need both bands or a version built only for those switch-pitch years, compare the 1965-1967 TH400 master kit. Every other part for this transmission is on our TH400 page.
An early 400 that has spent years in a heavy car often has a worn intermediate sprag, so inspect it while the unit is apart. If you want firmer shifts with a manual-hold first gear, the TransGo 400-1-2 shift kit goes in with the valve body out. The TH400 wear points guide covers the hard-part checks worth doing during the rebuild.
| Fits | TH400 1964 |
| Part type | Master Rebuild Kit |
| Condition | New |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
The kit maker lists it for 1965-up THM400 units. Most soft parts carried over from the first year, but send us the year, VIN and the ID plate number and we will confirm fitment before you order for a 1964 car.
It includes the front band. The rear band is not in this kit, so inspect it during teardown and replace it separately if it is glazed or unevenly worn.
The vacuum modulator controls line pressure from engine vacuum. When the diaphragm leaks, the engine draws fluid in and burns it, and shifts turn harsh or late. Replacing it during a rebuild removes one of the most common TH400 comebacks.
Use Dexron ATF. A completely dry transmission with an empty converter needs roughly 10 to 11 quarts plus the cooler and lines. Finish filling by the dipstick at operating temperature.
Check the intermediate sprag, low roller clutch, thrust washers and the pump pressure regulator bore. Replace any of those that show wear, and consider a shift kit while the valve body is out.
