The Isuzu 5115990023 is a genuine OEM crankshaft thrust bearing designed for various Isuzu engines, including the 4JG2, 4JG2T, and 4JG2-TC. This critical component ensures proper crankshaft positioning and reduces axial play, contributing to engine longevity and smooth operation. It is compatible with a wide range of Isuzu vehicles such as the ELF (NPR) series, WIZARD, BIGHORN, TROOPER, RODEO, MU, and F-Series trucks (FRR, FSR, FTR, FVR). This part supersedes earlier Isuzu part numbers 5115990020, 5115990021, and 5115990022, and is also cross-referenced with Mazda 1K0011399 and GM 97186043.