TH400 Sprag Clutch 1964, new and ready to install. Fits the TH400. Ships fast from the USA.
The Turbo Hydra-Matic 400 went into production for 1964, and this listing is for owners of early and smooth-drum 400s who need a new intermediate sprag: 34 elements with hardened end caps, cross-referenced to BorgWarner 06763AM. If you are restoring a Cadillac, Chevelle or Camaro with a sprag-type 400, or building any 400 that uses a smooth-hub direct drum, and second gear slips or the old sprag came out in pieces, this is the part.
A sprag is a ring of small figure-eight shaped elements held between cages and an energizing spring. Turned one way, the elements lay over and slide; turned the other way they stand up and jam between the inner and outer race. In the 400 the inner race is the smooth hub of the direct clutch housing and the outer race is splined to the intermediate clutch plates. Apply the intermediate clutch for second gear and the sprag stops the direct housing and sun gear from turning backward. Apply the direct clutch for third and the housing runs forward, so the sprag freewheels. The listing notes most factory sprags had fewer elements, around 19; the 34-element design spreads the load over more contact points.
An old 400 that has sat for years often has varnished valves and hardened seals, so check fluid, the modulator and line pressure first. Then compare Drive with manual Second on a road test; a second gear that only holds with the band applied points at the sprag or intermediate clutch. With the unit apart, hold the outer race and turn the drum. It should lock instantly one way. Our TH400 common problems guide covers the pressure checks and the pump failure guide helps rule out low pressure from a worn pump.
The listing names 1965-1977 TH400 applications, including Cadillac DeVille, Eldorado, Fleetwood and Calais and Chevrolet Chevelle, Caprice and Camaro, plus 4L80-E and 4L85-E units through 2009. It is for smooth cam (sprag type) drums only and will not fit lobed, roller-style drums. Our title says 1964 because that is the year buyers search for an early unit, but the drum decides fitment: look at the direct drum hub, or send us the year, vehicle and VIN. All our Turbo 400 parts are on the TH400 parts page, and the BorgWarner-boxed TH400 intermediate sprag is the same design.
Before the drum goes in, check rotation: holding the outer race, the drum should turn freely in its normal forward direction and lock the other way. GM's 400 manual lists a backwards-installed intermediate one-way clutch among its trouble causes. Inspect the drum hub and outer race; a pitted or stepped race will let new elements roll over. Install the drum with a twisting motion so the outer race indexes with the intermediate plates. On an early unit, replace the intermediate frictions and steels and every seal; a TH400 master rebuild kit for 1964-up covers the soft parts, and the TH400 clutch module adds frictions. Fill with Dexron type ATF.
| Fits | TH400 1964 |
| Part type | Sprag Clutch |
| 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.
It fits 400s that use a sprag on a smooth-hub direct drum. The listing names 1965-on applications, so check the drum hub or send us your year and VIN before ordering for a 1964 unit.
Some 400s use an intermediate roller clutch running on a cam hub with lobes. A sprag needs a smooth round hub, so it cannot run on a lobed drum.
The listing says most factory sprags had about 19 elements. This replacement has 34, which spreads torque across more elements.
Manual Second applies the front band on the direct drum. If second holds there but slips in Drive, the intermediate sprag or intermediate clutch is not holding.
No. The TH400 uses Dexron type ATF.
