FMCSR 393.89: Missing or Inadequate Driveshaft Protection

No. A 393.89 citation will not result in an out-of-service order. Across our entire inspection database, this violation has never been placed out of service—our records show a 0.0% OOS rate across all 204 citations on file. This is significantly lower than the 31.4% all-FMCSR average OOS rate, meaning driveshaft protection violations are treated as correctable maintenance items rather than safety-critical defects.

First: document the citation details and photograph the driveshaft area. Second: inspect the driveshaft protection guard for damage, gaps, or missing fasteners. Third: review co-occurring violations from recent inspections—our data shows wheel fasteners, brake chambers, and slack adjusters often appear in the same inspection. Have a qualified mechanic verify the driveshaft guard meets FMCSR standards and repair or replace it if needed. Keep proof of repair for your compliance file.

No, 393.89 is one of the least frequently cited vehicle maintenance violations. It ranks #1208 out of 3,036 FMCSR codes by citation volume, with only 65 citations in the last 12 months. Compare this to peer codes: inoperable required lamps (393.9) has 180,097 citations with a 6.9% OOS rate, and slack adjuster defects (393.47E) has 180,363 citations. Your violation is uncommon and carries no out-of-service risk.

While there is no mandatory out-of-service deadline, you should repair the driveshaft protection promptly because any subsequent inspection finding the same defect strengthens enforcement action and increases fleet risk profiles. Our inspection records show sporadic enforcement with peaks in May and July 2025 (14 and 17 citations respectively), suggesting regional or seasonal attention. Fix the guard before your next roadside stop or scheduled inspection.

Massachusetts and California account for most 393.89 citations in the last 180 days. Massachusetts has 8 citations, California has 7, and Pennsylvania, Tennessee, Texas, Ohio, and Hawaii each have 1. All of these have a 0.0% out-of-service rate. If you operate in MA or CA, prioritize driveshaft guard inspections as part of your pre-trip routine.

Three Bear Rentals LLC (USDOT 525298) has the highest count with 6 citations across our database. ABM Industry Groups LLC, Mountain Resort Services, Go Trek USA LLC, and A&M Limousine Co Inc each have 4 citations. These are primarily bus operators and shuttle services. If you work for a carrier with multiple 393.89 citations, ensure driveshaft guards are included in your fleet's preventive maintenance schedule.

Yes. Any FMCSA citation can be contested through the DataQs (Crash, Inspection, Violation Questionable) system if you have evidence the violation was incorrectly documented or identified. Since 393.89 is an equipment defect, you would need to show either that the driveshaft protection was actually in compliance at the time of inspection, or that the inspector made a factual error. Gather inspection photos, maintenance records, and repair documentation to support your challenge.

Across our 13 million inspection records, approximately 50+ carriers have received 393.89 citations. Three Bear Rentals LLC leads with 6 citations; the next tier includes five carriers with 4 citations each, and multiple carriers with 3 citations. This is a low-frequency violation concentrated in bus and shuttle operators. If you manage a fleet, driveshaft guard maintenance should be part of your preventive maintenance program to avoid becoming a repeat violator.