When the filter in a TH400 or 3L80 unit is clogged or worn, fluid restriction starves the hydraulic circuit and the transmission begins to show it through soft shifts, pressure loss, or outright slipping. This listing is a single filter unit cataloged under the TH425 designation, covering TH400 and 3L80 transmissions built from 1966 through 1978.The filter is pulled from REMCO stock that has been in the automatic transmission parts business since 1991. Each order is filled individually. A part list is included with the shipment.This is not a kit. There is no gasket, no pan bolt set, no seal, and no additional hardware in the box. The total shipping weight is 1.5 lb, which reflects the filter alone. If your job calls for a pan gasket or other components, those need to be sourced separately.Before placing the order, locate the transmission code stamped or tagged on the unit and confirm it reads TH400, 3L80, or TH425. Also verify the build year of the transmission falls between 1966 and 1978. Ordering by vehicle year alone is not reliable for this generation of units because production overlaps and drivetrain swaps are common. Match the transmission code directly. Replacing this filter restores proper fluid flow through the valve body, preventing pressure drops that cause erratic shifts or slipping in TH400 and 3L80 units. This listing is for the filter only. It does not include a gasket, seal, pan, or any other component. Verify what your rebuild or service job requires before ordering. The TH425 catalog designation on this filter means it is the correct geometry for that application within the TH400 and 3L80 family, not a universal fit adapted to the unit. Contents: one transmission filter, 1.5 lb. No additional parts are included. Confirm the count before closing the unit. Before ordering, match the transmission code on the unit itself to TH400, 3L80, or TH425, and confirm the build year falls within 1966 to 1978.
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![TH400 [ 3L80 ] [66-78] PRECISION Automatic Transmission Overhaul Gasket Kit-Complete Set with High-Quality Seals Gaskets & Components](https://cdn.shopify.com/s/files/1/0505/1200/3252/files/ADP-02785B_b56f42a8-72bf-4d7a-b13f-152cf7eb829a.jpg?v=1761762894&width=480)