What This Panel Does
This is the lower aerodynamic skin that sits under the driver door and step area on a T680 Next Gen cab. It closes out the gap between the cab step assembly and the chassis fairing, keeping airflow attached down the side of the truck instead of tumbling into the drive wheels and frame rails.
It is a cosmetic and aerodynamic part, not a structural one. Nothing load-bearing hangs off it. But a broken or missing panel leaves the step box, air lines and wiring behind it exposed to spray, salt and stone chips, and it looks rough on a DOT walkaround and at trade-in time.
The A33-1255-200 is the driver-side, left-hand piece. Panels on this area of the cab are handed, so the passenger-side part is a different shape and will not flip over and bolt on. Confirm which side you are replacing before you order anything.
Why These Numbers Cross
A33-1255-200 and A33-1255-100 share the same base number, A33-1255. The trailing three digits are the variant suffix the manufacturer uses to separate handing and revision level within a single panel family. Same mounting pattern area, same general footprint, same place on the cab.
In practice, that means a truck that was built or previously repaired with A33-1255-100 on the lower driver door area is the same application this aftermarket panel is built to serve. The numbers are listed here for identification only. PartStop is not affiliated with, endorsed by or authorised by Kenworth or PACCAR.
Treat a suffix difference as a reason to check, not a reason to assume. Revision suffixes sometimes track a change in fastener hole count, trim edge profile or a running production change. Pull the number off the old panel or run the VIN before you commit.
Check Before You Order
Get the broken panel off the truck, or at least get your eyes on the back of it. Factory panels are usually stamped or labelled on the inside face. That number, not the one in a catalogue listing, is what you match against. If the panel is gone entirely, go to the VIN and have the build sheet pulled.
Then inspect the mounting hardware and the brackets behind it. Panels in this position rarely break on their own — they break because something hit them, or because the fastener bosses let go and the panel flapped until it cracked. Replacing the skin without fixing stripped clips or a bent bracket gets you a second broken panel.
A33-1255-200 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to A33-1255-200. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| OE/Cross-Ref | A33-1255-100 |
Frequently asked questions
Will A33-1255-200 fit my T680 if my old panel says A33-1255-100?
Those numbers cross within the same panel family, so it is a reasonable starting point. It is not a fitment guarantee. Verify with the VIN or by matching the number stamped on the back of the panel you are taking off before you order.
Is this the driver side or passenger side?
This is the left-hand, driver-side panel. The under step fairing panels are handed, so the right-hand piece is a different part with a different shape. Make sure you are ordering for the correct side of the cab.
Do I need to replace the brackets and clips too?
Often yes. These panels usually crack after an impact or after the fasteners loosen and let the panel vibrate. Inspect the mounting bosses, clips and any bracket behind the panel while it is off the truck. Install a new panel on damaged hardware and it will break again.
Not sure it fits? We check before you pay.
Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
Need the part, not just the reading?
Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.