Verdict · NHTSA data
Limited data — recalls on file
NHTSA has just 0 complaints on file for the 1979 Mack RWL — too few to judge reliability from owner reports alone — but 6 recall campaigns apply to this year, so any used example should have its VIN checked for completed recall work.
0
NHTSA complaints
6
Recalls
0
Investigations
0
Crash-involved
0
Fires reported
0
Injuries
0
Deaths
—
NCAP overall
6 NHTSA recall campaigns on file. Recall repairs are free at franchised dealers.
Defect
MOUNTING OF THE PITMAN ARM MAY LOOSEN AND LEAD TO EXCESSIVE WEAR IN EITHER THE PITMAN ARM SPLINES OR THE STEERING GEAR SHAFT SPLINES, OR BOTH. THIS CONDITION IS DUE TO INCORRECT TIGHTENING OF THE MOUNTING SCREWS DURING ASSEMBLY.
Remedy
THE DEALER WILL INSPECT AND PROPERLY TIGHTEN THE PITMAN ARM RETAINING SCREWS.
Defect
THE SPRING SEAT PLATE, LOCATED BETWEEN THE AXLE HOUSING AND THE SUSPENSION SPRINGS, MAY DEFORM DUE TO SPRING BENDING. AS A RESULT, THE CLAMPING FORCE IN THE ASSEMBLY MAY BE REDUCED. LOSS OF CLAMPING FORCE COULD CAUSE SPRING FAILURE AND THE AXLE WILL DISLOCATE. ALSO, THE TIRE COULD COME INTO CONTACT WITH THE SPRING.
Remedy
THE DEALER WILL REPLACE THE EXISTING SPRING SEAT WITH A NEWLY FABRICATED SEAT WHICH IS WELDED TO THE HOUSING. AN IMPROVED SPRING CLAMPING PLATE AND NEW SPRINGS WILL ALSO BE INSTALLED WITHOUT CHARGE.
Defect
THE FLANGE HEAD PINCH BOLTS USED IN THE YOKES OF THE STEERING SHAFT ASSEMBLIES MAY HAVE BEEN OVERSTRESSED DUE TO THE BOLTS NOT BEING TIGHTENED TO SPECIFICATIONS. AS A RESULT, THE PINCH BOLTS COULD BREAK WHILE IN SERVICE.
Remedy
FLANGE HEAD PINCH BOLTS WILL BE REPLACED WITH STANDARD GRADE 8 FASTENERS WITHOUT CHARGE TO OWNER.
Defect
THE PITMAN ARM RETAINING NUT MAY NOT HAVE BEEN TORQUED TO MANUFACTURER SPECIFICATIONS. THIS COULD RESULT IN INADEQUATE RETENTION OF THE NUT AT THE OUTPUT SHAFT, ALLOWING THE PITMAN ARM TO BECOME LOOSE.
Remedy
DEALER WILL INSPECT AND RETORQUE PITMAN ARM, IF NECESSARY, AT NO COST TO OWNER.
Defect
IN THE EVENT OF TURBOCHARGER COMPRESSOR WHEEL FAILURE, ONE OR MORE OF THE FOUR CAPSCREWS THAT HOLD THE TURBOCHARGER TOGETHER MAY BE STRUCK BY PARTS OF THE COMPRESSOR WHEEL, RESULTING IN THE CAPSCREWS BEING DAMAGED. IF THESE CAPSCREWS ARE DAMAGED TO THE POINT THAT THEY ALLOW THE COMPRESSOR BACK PLATE TO DISLOCATE FROM THE TURBOCHARGER BEARING HOUSING, ENGINE LUBRICATING OIL MAY BE ALLOWED TO ESCAPE UNDER PRESSURE, CONTACTING THE ENGINE EXHAUST MANIFOLD SECTIONS OR TURBOCHARGER TURBINE HOUSING.
Remedy
DEALER WILL INSTALL A SHIELD FOR THE HEADS OF THE FOUR CAPSCREWS, ALONG WITH STRONGER SAE 8 GRADE 8 CAPSCREWS, IF NECESSARY, AT NO COST TO OWNER.
Defect
IT HAS BEEN DETERMINED THAT TWO SCREWS THAT ARE PART OF THE BEARING ASSEMBLY LOCATED AT THE CAB DASH SHEET MAY NOT HAVE BEEN TIGHTENED PROPERLY. AS A RESULT, THE UPPER STEERING SHAFT MAY BE FREE TO "FLOAT" THROUGHOUT MUCH OF ITS LENGTH WHICH MAY RESULT IN INADEQUATE ENGAGEMENT IN THE SLIP SPLINES OF THE LOWER STEERING SHAFT. AXLE ARTICULATION COULD RESULT IN DISENGAGEMENT OF THE LOWER STEERING SHAFT SLIP SPLINES.
Remedy
DEALER WILL INSTALL A SLEEVE BETWEEN THE DASH SHEET BEARING AND THE UPPER STEERING SHAFT LOWER YOKE TO ASSURE POSITIVE UPPER STEERING SHAFT LOCATION.
The record is thin — 0 NHTSA complaints — so owner-report data can't strongly confirm reliability either way, though 6 recalls should be verified as completed.
Yes — NHTSA lists 6 recall campaigns affecting the 1979 Mack RWL. Recall repairs are free at franchised dealers; check the VIN at nhtsa.gov/recalls to confirm the work was done.
Based on NHTSA ODI data through June 2026. Complaints are consumer-reported and unverified. Updated July 5, 2026.
Compiled by Sharon Ben-Moshe, Founder.