TH400 Sprag Clutch 1991-95, new and ready to install. Fits the TH400. Ships fast from the USA.
This is a two-piece one-way clutch set for the GM Turbo 400 and its electronic successors, the 4L80E and 4L85E: one low roller clutch and one heavy duty 34-element intermediate sprag, both made by BorgWarner. If your 400 or 4L80E has no first gear in Drive, flares or drops to neutral on the 1-2 shift, or you are rebuilding and want to replace both one-way clutches at once, this set covers both positions in one order. The 34-element sprag replaces the weaker 16-element sprag found in older units.
The 400 geartrain uses two one-way clutches, and this set replaces both. The low roller clutch rides inside the reaction carrier, whose bore is its outer race. In Drive first it locks the reaction carrier so the transmission can pull, then freewheels when the 1-2 shift happens. The intermediate one-way clutch rides on the direct clutch housing, with its outer race splined to the intermediate clutch plates. When the intermediate clutch applies for second gear, the one-way clutch holds the direct housing and sun gear from turning backward, then overruns when third gear applies the direct clutch. Because each one freewheels at the right moment, the 1-2 and 2-3 shifts happen without fighting each other. Early 400s used a sprag in the intermediate position, later units moved to a roller design, and the 4L80E went back to a sprag. This set is for the sprag-type direct housings.
The range test is the cheapest diagnosis. Manual Low applies the rear band, which holds the same reaction carrier the low roller clutch holds; if Low pulls but Drive first does not, the roller clutch is slipping. Manual Second uses the front band to hold the direct housing; if second holds in manual Second but slips in Drive, look at the intermediate sprag or the intermediate clutch pack. Check fluid level and line pressure first, because low pressure causes slips in every range. Our TH400 common problems guide and delayed engagement guide cover those first checks.
The set is listed for TH400, 4L80E and 4L85E transmissions with non-roller (sprag-type) drums, 1964-on. Our title says 1991-95 because those are the early 4L80E years buyers search by, but fitment is decided by the drum, not the year. Look at your direct clutch housing before ordering: if the intermediate position uses a caged roller clutch rather than a sprag, this sprag will not fit that housing without a sprag-type drum. If you need only the intermediate sprag, see our 34-element intermediate sprag. Send us the year and VIN or a photo of your drum if you are unsure, and see all 400 parts on the TH400 parts page.
| Fits | TH400 1991-95 |
| 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.
One low roller clutch and one heavy duty 34-element intermediate sprag, both BorgWarner. It covers the two one-way clutch positions in the TH400, 4L80E and 4L85E geartrain.
Only if that unit has a sprag-type direct housing. Many mid-production 400s used an intermediate roller clutch instead. Look at your direct housing before ordering, or send us a photo.
More elements spread the holding load over more contact points. The 34-element sprag replaces the weaker 16-element version used in older units and is the standard intermediate sprag in the 4L80E.
Very likely the low roller clutch. Manual Low applies the rear band to hold the reaction carrier, so if Low works and Drive first does not, the roller clutch is the usual cause.
The intermediate clutch plates, and the reaction carrier if its roller race is pitted. Most installs are part of a rebuild with a full overhaul kit.
