Drive Axle Ratio Identification: Identification

1984 GMC Suburban K2500, 5.7 M, StandardSECTION Identification

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.

GENERAL MOTORS AXLE RATIO IDENTIFICATION (FRONT)

Code Ratio
BRW, GRK, SAA, SDH 2.73:1
BSX, GRL, SBA, SBB 3.08:1
TFA, WC 3.23:1
THA, THD, WF, WH 3.42:1
TBA, TBB, TBD, TBF, TBJ, WM 3.73:1
TCA, TCB, TCC, MFA 4.10:1
TDA, TDB 4.56:1
GENERAL MOTORS AXLE RATIO IDENTIFICATION (REAR, NON-LOCKING)

Code Ratio
BN3, BW3 2.56:1
BB3, BRA, BRD, BRC, BRD, BRJ, BRM, BRR, BX3, BZA, BZB 2.73:1
BC3, BSA, BSC, BSD, BSK, BSN, BRX, BS3, BY3, CM3, CR3 3.08:1
BAA, BAB, BAC, BAD, BCS 3.21:1
BDB, BDD, CZN 3.23:1
BBC, BBD, BBJ, BBK, BBN, BBR BBU, BBX, BD3, BT3, BWH, BZ3, CX3 3.42:1
BCA, BCC, BCF, BCW, BCX, BCY, BFA, BFH, BFN, BU3, BUC, BUK, BVA, CY3 3.73:1
BCZ, BHA, BHC, BHR, BHW, BHY, BJC 4.10:1
BTA, BTC, BTH 4.11:1
BKA, BKC, BKM, BKR, BKU, BKX, BKZ, BMB, CZT 4.56:1
BMA, GDA 5.13:1
GENERAL MOTORS AXLE RATIO IDENTIFICATION (REAR, LOCKING)

Code Ratio
CB3, CH3 2.56:1
BH3, BRB, BRF, BRH, CC3, CJ3, CS3, CV3 2.73:1
AZ3, BJ3, BSB, BSF, BSH, CD3, CW3 3.08:1
BDC, BDF, CZU 3.23:1
BA3, BBA, BBF, BBH, BBM, BBS, BBT, CF3, C23 3.42:1
BCB, BCD, BCH, BCJ, BCR, BDA, BFC, BFD, BFF, BFJ, BFM, BFR, BFW, BFX, BFY, BM3, CZW, DA3 3.73:1
BFC, BHB, BHD, BHH, BHJ, BHS, BHU, BJA, BJB, BZX 4.10:1
BKB, BKD, BKN, BKS, BKW, BKY, BMA, BMC, BMF, CZY 4.56:1
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

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

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.