When the front band in a TH400 or 3L80 automatic transmission wears out, the unit loses its ability to hold the drum firmly during apply, and the result shows up as a slip or a harsh, inconsistent shift. This listing is for a single flex-style front band, 1 inch wide, built for TH400 and 3L80 units in production from 1964 onward.
The flex construction matters here because a rigid band contacts the drum surface unevenly as it wears, concentrating pressure at the edges. A flex band bends with the drum contour and spreads that clamping load more evenly across the full contact width. That characteristic is especially relevant in units that see variable line pressure or have accumulated wear on the servo components, where consistent band contact becomes harder to maintain.
This is a single component: one front flex band, 1 inch wide, 1 lb. There is no servo piston, no apply pin, no anchor pin, no struts, and nothing else in the package. If your service requires those parts, they need to be sourced separately. The part is checked against its record at the time of packing, and a parts list is included in the box.
Before ordering, confirm the transmission code is TH400 or 3L80, that the application is the front band position, and that your unit takes the 1-inch width. If you have the old band in hand, measure it. TH400 applications run from 1964 up through current use in industrial and performance builds, so the range is wide and the band position can vary by application.
- Restores holding force at the front servo position in TH400 and 3L80 units, addressing slipping or delayed engagement caused by a worn or broken band.
- This listing covers the band only. No servo, anchor pin, apply pin, struts, or other components are included. Verify your full parts need before ordering.
- The flex design of this band allows it to conform evenly around the drum surface, which helps distribute clamping load more consistently than a rigid band during apply cycles.
- One front flex band, 1 inch wide, weight 1 lb. Single piece shipment, checked against the part record before packing.
- Confirm your transmission is a TH400 or 3L80 and that the unit requires the 1-inch-wide front band before placing your order. Measure the existing band if possible.
What's in the box
- 1 x Band, Th 400 425 Flex Front [1wide]
Compatible vehicles
- Fits K2500 Panel Delivery 3/4 Ton 4WD [67].
| th 400 425 band flex front (1wide) 1964-up Automatic transmission |
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