What This Drum Is and Where It Goes
This is a 15-inch diameter, 4-inch wide brake drum built for steer axle duty, 10-bolt pattern, 11.25" drum I.D. Gunite's been making these for decades and the 3800X casting number is the one that shows up most on Freightliner, International, Peterbilt, Kenworth, and Volvo steer axles depending on the hub setup.
It's a heavy-duty piece — thicker wall than a lot of the cheap stamped stuff, made to handle steer axle heat and stopping loads without warping. That matters more on the front axle than people think, since a warped steer drum will chatter or pull under braking.
Steer axle drums see less wear than drive axle drums usually, but they still crack from heat cycling, especially on trucks doing mountain grades or heavy stop-and-go city work.
Why All Those Other Numbers Cross to 3800X
The 3726X, 9003800X, and the 65548/55548B series numbers you see in the cross table are all the same physical drum under different casting or catalog numbers — Gunite's changed part numbering a few times over the years, and other brands picked up the tooling or built to the same spec. Same for the 9456 3800X and 10001781 aftermarket listings.
Before you order, don't just match the number off a catalog page — pull the number stamped on your old drum, or better, run your truck's VIN. Drum diameter and width are the easy part to check with a tape measure, but bolt pattern and hub pilot bore can vary between axle makes even when the drum looks identical. A drum that's a hair off on pilot diameter will still bolt up crooked and eat your wheel bearings.
If your old drum is scored bad enough you can't read the casting number, measure across the bolt holes and check the drum I.D. with a drum micrometer if you've got one. That'll get you in the right ballpark before you call us to confirm.
Ordering From PartStop
We stock these at the Tacoma counter, so if you're local and your rig's down, call ahead and we'll have it up front. Same-day pickup if we've got stock, otherwise it ships out fast — we move parts nationwide daily, not just around the Puget Sound.
Every drum we sell carries our 6+ month warranty. If it turns out to be the wrong fit or something's off with the casting, we'll sort it — just don't machine or drill it first, that voids things fast.
One more thing: if you're replacing one steer drum, check the other side too. Drums usually wear in pairs, and running a new one against an old warped one just means you're back under the truck in a month.
3800X Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 3800X. 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 | 3726X, 9003800X, 65548, 55548B, 65548B, 85123448002, 3123448002, 107164, 10009920, 33983800X |
| Aftermarket | 9456 3800X, 10001781, 3726, 9001X, G1213X, 89870BK, 90660BK, 38BD00B, 03 123254 002, 03123448002 |
| Alliance | N42A154B |
Frequently asked questions
Does 3800X fit my Freightliner steer axle?
Probably, but confirm before you order. The 3800X cross-references across a bunch of makes with the same 15x4, 10-bolt, 11.25" I.D. spec, but hub pilot bore can differ. Pull the number off your old drum or run your VIN — we'll match it up at the counter.
Is this the same as the Alliance N42A154B?
Same drum spec, different brand stamping. Alliance builds to the same 15x4/10-bolt/11.25" dimensions under their own number. Physically interchanges, but always double-check against your old part number since Alliance sometimes runs slightly different casting tolerances.
Can I use this on a drive axle instead of steer?
No — this is built and rated for steer axle duty. Drive axle drums usually see different heat and load specs even if the bolt pattern looks similar. Don't swap axle positions on drums without checking the actual spec sheet.
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.