The CAT 299D3 undercarriage is a wear system, not a list of unrelated parts. Rubber tracks, sprockets, idlers, rollers, tension and alignment all affect each other, which is why a track replacement is the right time to inspect the complete machine.
Need CAT 299D3 undercarriage parts?
Cataloged track configuration: 450x86x60
CAT 299D3 undercarriage part numbers
| Component | Current TrackTECH reference | Check |
|---|---|---|
| Drive sprocket | 304-1916 | Verify installed component / serial configuration. |
| Front idler | 304-1878, 348-9647 | Verify installed component / serial configuration. |
| Rear idler | 304-1894 | Verify installed component / serial configuration. |
| Bottom roller | 304-1890 | Verify installed component / serial configuration. |
Configuration note: The CAT 299D3 and 299D3 XE should not be assumed identical without verifying the exact machine designation.
When should you replace a sprocket?
Replace based on actual wear and the machine manufacturer's service criteria. Hooked, pointed or uneven teeth can pull on the drive lugs instead of engaging them cleanly. That is especially important when installing new rubber.
When should you replace rollers or idlers?
Look for leakage, bearing play, binding, damaged flanges, flat spots and obvious misalignment. A seized roller or loose idler can create localized wear and contribute to de-tracking.
Do not use new tracks to hide an undercarriage problem
If the old track repeatedly de-tracked, ratcheted, wore one side, or tore drive lugs, diagnose that symptom before installing the replacement. See Why Does My Rubber Track Keep Coming Off? and Rubber Track Ratcheting or Skipping Under Load.
Shop the complete 299D3 machine collection
The live CAT 299D3 Tracks & Parts collection is the current source for products, pricing and availability. If the part number on the machine conflicts with the catalog, verify the serial/configuration before shipment.