AT540 [71-UP] Automatic Transmission Filter Allison

When automatic transmission fluid cannot move ly through a clean Automatic Transmission Filter, every other component in the unit pays the price: pump wear increases, clutch apply pressure drops, and shift feel deteriorates in ways that are hard to trace back to the source. This Automatic Transmission Filter -- a flat stainless steel screen built for AT540, AT542, AT543, and AT545 units from 1967 onward -- addresses that problem at the source, giving the pump a clear, consistent path to draw fluid without restriction.

The stainless steel flat screen construction is the defining detail here. Unlike paper or fiber media that absorbs fluid, softens under heat, and eventually collapses or degrades, a steel screen maintains its geometry through temperature swings and pressure cycles. That means flow characteristics stay predictable across the life of the part, which matters when the hydraulic system depends on stable inlet pressure to operate correctly.

This is a single-piece item: one Automatic Transmission Filter screen, approximately 1 lb, intended for the AT540, AT542, AT543, and AT545 automatic transmission. No gaskets, no seals, no clutch or band components are included with this listing. If your job requires those parts as well, they need to be sourced separately -- check your application before placing the order.

To confirm fitment, locate the model identification on the transmission case and verify it matches one of the four codes listed. Year of manufacture should fall within the 1967-and-later range. When in doubt, cross-reference the tag on the unit rather than relying on vehicle records alone, since transmissions are sometimes swapped.

• Restoring proper fluid flow starts with a clean, unrestricted Automatic Transmission Filter -- a clogged or failed screen leads to pressure loss, erratic shifts, and internal wear that compounds fast.
• This listing is for the Automatic Transmission Filter only. It does not include any gaskets, seals, bands, clutch packs, or rebuild components. Confirm the rest of your parts list before ordering.
• A flat stainless steel screen holds its shape under heat and pressure cycles that would deform or collapse a fiber or paper element, keeping flow consistent across the service life of the Automatic Transmission Filter.
• One flat stainless steel Automatic Transmission Filter screen, approximately 1 lb. Fits AT540, AT542, AT543, and AT545 automatic transmission units built from 1967 onward.
• Before ordering, match the transmission model code on the unit itself -- AT540, AT542, AT543, or AT545 -- and verify the build year falls within the 1967-and-later application range.

What's in the box

• 1 x Steel Plate, ALLISON AT540 Automatic Transmission Filter

Compatible vehicles

• Fits B50 2 Ton School Bus [71-72], C3500 1 Ton - Pickup [88-00], C3500HD 1 Ton Truck [91-02], C40 1 1/2 Ton Truck [71-79], C80 2 1/2 Ton Truck [71-79], F80 2 1/2 Ton Tilt Cab [71-79], K3500 1 Ton 4WD - Pickup [88-00], P4T042 Stripped Chassis [80-84], P6S042 Stripped Chassis [91-96], P6T042 Stripped Chassis [83-90], R3500 1 Ton - Pickup [88-91], S50 1 1/2 Ton School Bus [73-79].