What This Alternator Is
The 40SI is a brushless, pad-mount heavy-duty alternator rated 12 volts and 275 amps. Brushless means no brushes or slip rings to wear, which is why fleets running high electrical loads — inverters, APUs, liftgates, heavy lighting — spec this frame over a smaller unit. Output stays high at idle, which matters on trucks that spend hours parked and loaded.
On a Freightliner Century, Argosy, FC80 or M2, the unit mounts to the engine pad with the stud terminals at the back. Before you order, look at the physical alternator on the truck: terminal layout, mount ear spacing, pulley groove count and pulley diameter. A 275A unit and a lower-amp unit from the same family can share a frame but differ at the pulley or the regulator plug.
Our 8600094 is an aftermarket direct replacement, not an OEM part. Every other number on this page belongs to another manufacturer and is listed for identification only — we are not affiliated with or authorised by any of them.
Why These Numbers Cross
This alternator family was built as one platform and then relabelled by truck builders, remanufacturers and distributors. Freightliner DR8600094, Mack 22899067, Volvo 21654110 and the Navistar numbers 3571135, 3571135C91, 3571135C92, 4053026C91 and 4053026C92 are chassis-side part numbers for the same 12V 275A unit fitted at build. Each builder assigns its own number to the same hardware.
The Leece Neville numbers — 4942PA, 4944PA, 4947PA, 4949PA, 4949GH, 4975PAA and the A0014942PA, A0014944PA, A0014947PA, A0014949PA, A0014949GH, A0014975PAA prefixed versions — are the manufacturer-side base numbers and their long-form equivalents. ZLN4975PAA and ZLN4949PAH show the same casting under a different catalogue prefix, and Prestolite/Autolite A0014949PAH sits in the same group.
Remanufacturers and distributors then added their own: Wilson 90-04-7097, 90-04-7105 and 91-04-7105, Power Select 8681N and 8681R (new and reman suffixes), Dixie Electric 101-40122 and Unipoint ALT-0271. Different label, same 40SI pad-mount frame. Treat the list as a starting point and confirm by the number stamped on your old unit or by VIN.
How These Fail And What To Check
Typical failure on a high-amp brushless unit is the rectifier or the internal regulator, usually after years of heat soak and vibration. Symptoms: low or no charge voltage, AC ripple on the system, batteries boiling or sulphating, dash charge warning. Load-test before you condemn it. A dead unit is often a loaded battery bank, a burnt ground strap or a corroded B+ stud, not the alternator.
When the new one goes on, clean the mount pad to bare metal, torque the B+ and ground connections to spec and check cable condition end to end. A 275A unit pushes serious current — undersized or corroded cable will cook the new alternator the same way it cooked the old one. Check belt tension and pulley alignment too; a worn tensioner eats bearings fast.
8600094 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 8600094. 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 |
|---|---|
| Cross-Reference | Freightliner DR8600094, Mack 22899067, Navistar 3571135, 3571135C91, 3571135C92, 4053026C91, 4053026C92, ZLN4975PAA, Volvo 21654110, Power Select 8681N, 8681R, Prestolite/Autolite A0014949PAH, ZLN4949PAH, Unipoint ALT-0271, Wilson 90-04-7097, 90-04-7105, 91-04-7105, Dixie Electric 101-40122, Leece Neville 4942PA, 4944PA, 4947PA, 4949PA, 4949GH, 4975PAA, A0014942PA, A0014944PA, A0014947PA, A0014949PA, A0014949GH, A0014975PAA |
Frequently asked questions
Will 8600094 fit my Freightliner M2 without modification?
It is built as a direct replacement for the 40SI 12V 275A application listed for Century, Argosy, FC80 and M2. That said, we cannot promise fitment from a model name alone. Confirm by VIN or by reading the number stamped on the alternator currently in the truck, and compare pulley and terminal layout before installing.
Is this the same as the Leece Neville 4949PA and A0014949PA numbers?
Those are manufacturer-side numbers for the same 40SI platform — the short base number and its long-form version. They are listed for identification only so you can confirm you are looking at the right unit. Match the physical part: mount ears, pulley, terminal stud positions and regulator connector.
My new alternator is not charging after install — what now?
Check the B+ cable and ground strap first, with the connections clean and torqued. Measure voltage at the alternator output stud and again at the battery; a large drop means cable or connection resistance. Also verify the ignition sense circuit is live. A weak or shorted battery in a parallel bank will drag output down and make a good alternator look dead.
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.