Section 3 (Drive Axle Ratio Identification): Identification

1984 GMC Pickup K2500, 5.7 M, StandardSECTION Identification
WARNING: This page does not describe the selected car, but rather 28 other vehicles, including the 1985 GMC Vandura Special, 1985 GMC Vandura, 1985 GMC Value Van, 1985 GMC Suburban, and 1985 GMC Safari. However, it is still accessible from the selected car via links, so may be relevant.

Identification code for rear axles is stamped on rear surface of right rear axle tube. Identification code for front axles is stamped on top rear of left axle tube. On Dana built front axles, axle ratio code is on tape stripe around right front axle tube.

"C, G, K & P" AXLE RATIO IDENTIFICATION (FRONT)

Code Ratio
HAN 2.73:1
HAP 3.08:1
HAU, MKB 3.23:1
HAR, HAW, MHC 3.42:1
HAS, HAT, MBC, TBA, TBB 3.73:1
GBB, MCD, TCA, TCB 4.10:1
TDA, TDB 4.56:1
"C, G, K & P" AXLE RATIO IDENTIFICATION (REAR, NON-LOCKING)

Code Ratio
BB3, BRA, BRD, BR3, BX3, CK3, CN3 2.73:1
BC3, BSA, BSC, BSD, BS3, BY3, CRE 3.08:1
GGF, GGK, GMA, GMG 3.21:1
BDC, BDB, BDD, BDF, HBG 2.23:1
BBC, BBD, BBJ, BBK, BBN, BBR, BD3, BT3, BZ3, CA3, CX3, HMR 3.42:1
BCY, BCW, BCX, BFA, BFK, BFN, BFU, BFW, BF3, BUE, CY3, GDF, GGG, GGL, GGP, GGY, GHB, GLH, GMB, GMH, GMP, GMW, HBB, GHN 3.73:1
BCZ, BHK, GDL, GGH, GGM, GGZ GHC, GHM, GHR, GLJ, GLP, GLS, GLU, GMD, GMK, GMS, HBD 4.10:1
BKC, BKN, GDC, GGJ, GGN, GHA, GHD, GHN, GHS, GLL, GLR, GLT, GLW, GMM, GMT, HBJ 4.56:1
BKT 4.88:1
BNB, GHU 5.13:1
TSA 5.29:1
TTA 5.83:1
"C, G, K & P" AXLE RATIO IDENTIFICATION (REAR, LOCKING)

Code Ratio
BH3, BRF, BRH, CC3, CJ3, CS3, CU3 2.73:1
AZ3, BJ3, BRB, BSB, BSF, BSH, CD3, CT3, CW3 3.08:1
HBH 3.23:1
BA3, BBA, BBF, BBH, BBM, BBS, BBT, BK3, CF3, CZ3, HMS 3.42:1
BDA, BFC, BFD, BFF, BFH, BFJ, BFM, BFR, BFX, BFY, BM3, DA3, GDG, GGU, GHF, GHJ, GLK, GMC, GMJ, GMR, GMX, HBC, HPB 3.73:1
BJA, BJB, BJD, GDK, GGR, GGW, GHG, GHK, GLM, GLX, GMF, GML, HBF 4.10:1
BKD, GDD, GGT, GGX, GHH, GHL, GHP, GHT, GLN, GLY, GMN, GMU, HBK 4.56:1
ASTRO, SAFARI & "S" SERIES AXLE RATIO IDENTIFICATION

Code Ratio
Conventional Rear Differentials
FAA 2.56:1
FCA, FCB 2.73:1
FFA, FFB, GNH, GNM, GNX 3.08:1
FMA, FMB, GNJ, GNN, GNT, GNY, GPB 3.42:1
FRA, FRB, GNK, GNP, GNU, GNZ, GPC, GPG 3.73:1
FSA, FSD, GNL, GNR, GNW, GPA, GPD, GPH 4.11:1
Locking Rear Differentials
FBA 2.56:1
GNS 3.08:1
GPF 3.42:1
Front Differentials
GBD 3.42:1
GBF 3.73:1
GBG 4.11:1
RENDER: 1.0x

NO RELATED

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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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