Workshop Notes: Isuzu 3-Groove Crankshaft Pulley for 4JB1 / 4KH1 Engines

If you've been working on Isuzu TFR55 or NKR55 trucks for a while, you know that front-end vibration can eventually take a toll on the accessory drive. We recently brought in a fresh batch of these 3-groove damper hubs (OE part numbers 8944548680 and 8-94454868-0) specifically to address this issue for the 4JB1 and 4KH1CT5H1 diesel motors. Here is exactly what you need to know about this replacement part before installing it.

Because engine bays vary wildly across the Isuzu commercial fleet, it's easy to grab the wrong part. For visual reference, here is how this 3-groove unit compares to the rest of the family:

A bad crankshaft pulley almost always ruins the alternator belt eventually. We also supply the matching charging units if you are doing a complete front-end rebuild.

If you aren't sure if the 8944548680 is the exact one you need, check this simple breakdown of the most common setups we handle daily:

• Got a TFR or UCS17 with the 4ZE1 MPI engine? You probably need the 2-Groove version (OE: 8941742811, 8970731570).
• This Featured Part: The 3-Groove standard for TFR55/G5/NKR55 running the 4JB1 or 4KH1 (OE: 8944548680, 8-94454868-0).
• Working on a heavier NPR or 700P with the 4HK1-TCS? Look for the 3-Groove Heavy Carrier (OE: 8980040243, 8-98004024-3).
• For the NKR55G4/NKR77G5 equipped with the 4KH1-TCG50, you'll need the larger 4-Groove setup (OE: 8972042040, 8-97204204-0).

We don't just push paper. Our team has been deeply involved in the commercial truck parts ecosystem since 1997. Here are a few unedited photos from our local staging warehouse and showroom where we physically handle these components.