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Find GCWR - Published Towing Guides

Use Towing Guides Below OR (for Diesel) First Check Diesel Supplement then Owners Manual (gasoline and diesels that are not in diesel supplement)

Starting in 2019, most towing models have a Trailering Sticker near the Federal Certification label on the Drivers Door Jamb.

For 2018 and older Models - Use Owners Manual Links Below OR (for Diesel/Duramax) Check Diesel Supplement

Cheverolet/GMC Manuals 2018 and older (Search Year & Model|Choose Manual or Trailering Guide|Look in Driving/Towing section)

GM Vehicle VIN Decoder for Axle Ratio

RPO (Regular Production Options) Codes List - A complete List of the definitions for the three-digit option codes that can be found on the RPO label. This label is usually titled "Service Parts Identification" and is most often found in the glove compartment or on the Driver's side door jamb (also called the B-pilar) - near the Federal certification label. The rear axle ratio codes most often begin with a "G". Occasionally "F" or "H" will be the starting prefix. See partial list of RPO axle codes below

GMC/Chevrolet RPO Axle Codes

RPO Code Description Ratio
F16 Transaxle Final Drive 2.53
F17 Transaxle Final Drive 2.84
F18 Transaxle Final Drive 2.65
F25 Transaxle Final Drive 3.32
F29 Transaxle Final Drive 2.82
F36 Axle Front 2.19
F45 Axle Front 2.93
F47 Axle Front 2.73
F57 Axle Front 3.15
F62 Transaxle Final Drive 2.39
F67 Transaxle Final Drive 3.19
F68 Transaxle Final Drive 3.45
F75 Transaxle Final Drive 3.18
F77 Transaxle Final Drive 3.73
F79 Transaxle Final Drive 2.97
F82 Transaxle Final Drive 3.23
F83 Transaxle Final Drive 3.05
F90 Axle Front 2.73
FA0 Rear 5.77
FA1 Rear 2 Speed 4.88/6.94
FA2 Rear 2 Speed 4.88/6.94
FH5 Transaxle Final Drive 2.81
FH6 Axle Front 3.64
FH7 Transaxle Final Drive 4.12
FH8 Axle Front 2.40
FH9 Transaxle Final Drive 2.60
FJ1 Axle Front 4.18
FJ2 Axle Front 3.74
FJ3 Transaxle Final Drive 3.35
FJ4 Axle Front 4.53
FJ5 Axle Front 4.19
FJ7 Axle Front 4.56
FP0 Transaxle Final Drive 2.55
FP1 Transaxle Final Drive 2.72
FP2 Transaxle Final Drive 3.58
FP3 Transaxle Final Drive 2.73
FP4 Transaxle Final Drive 2.69
FP5 Transaxle Final Drive 2.95
FP6 Transaxle Final Drive 3.54
FP7 Transaxle Final Drive 3.73
FP8 Transaxle Final Drive 3.54
FP9 Transaxle Final Drive 3.54
FQ2 Transaxle Final Drive 3.48
FQ3 Transaxle Final Drive 2.86
FQ4 Transaxle Final Drive 3.57
FQ6 Transaxle Final Drive 4.12
FQ8 Transaxle Final Drive 2.96
FQ9 Transaxle Final Drive 3.21
FR2 Transaxle Final Drive 2.93
FR3 Transaxle Final Drive 3.69
FR6 Transaxle Final Drive 3.84
FR7 Transaxle Final Drive 3.95
FR8 Axle Front 4.17
FR9 Transaxle Final Drive 3.29
FV0 Transaxle Final Drive 3.67
FV1 Transaxle Final Drive 3.72
FV2 Transaxle Final Drive 4.18
FV3 Transaxle Final Drive 3.11
FV4 Transaxle Final Drive 3.71
FV5 Transaxle Final Drive 4.19
FV6 Transaxle Final Drive 4.24
FV7 Transaxle Final Drive 4.29
FV8 Transaxle Final Drive 4.31
FV9 Transaxle Final Drive 4.53
FVO Transaxle Final Drive 3.67
FW2 Transaxle Final Drive 3.06
FW3 Transaxle Final Drive 4.02
FW4 Transaxle Final Drive 3.89
FW5 Transaxle Final Drive 4.10
FW6 Transaxle Final Drive 3.42
FW7 Transaxle Final Drive 3.83
FW8 Transaxle Final Drive 4.28
FW9 Transaxle Final Drive 3.43
FWS Transaxle Final Drive 4.10
FX1 Transaxle Final Drive 3.94
FX2 Transaxle Final Drive 2.66
FX4 Transaxle Final Drive 3.35
FX8 Transaxle Final Drive 3.61
FY1 Transaxle Final Drive 2.36
FY3 Transaxle Final Drive 3.79
FY5 Transaxle Final Drive 3.52
G11 Transaxle Final Drive 2.56
G44 Axle Rear 3.07
G72 Axle Rear 2.14
G75 Axle Rear 3.62
G76 Positraction Rear
G80 Not Open Diff – Positraction / Limited Slip / Typ. Gov-Lock
G81 Positraction Rear Axle
G82 Axle Rear 4.56
G84 Axle Rear 4.10
G86 Axle Rear, Limited Slip
G87 Ring Gear, 8.5″
G89 Ring Gear, 7.5″
G90 Rear 3.15
G91 Special Highway Rear Axle 3.08
G94 Axle Rear 3.31
G96 Axle Rear 3.55
G97 Axle Rear 2.73
GH0 Axle Rear 3.54
GH2 Axle Rear 2.29
GH3 Axle Rear 2.77
GH4 Axle Rear 2.92
GH7 Axle Rear 2.73
GJ1 Axle Rear 5.38
GJ2 Axle Rear 5.13
GK7 Axle Rear 4.78
GK8 Axle Rear 4.33
GK9 Axle Rear 4.63
GL0 Axle Rear 5.13
GL3 Axle Rear 6.17
GM1 Axle Rear 2.59
GM2 Axle Rear 3.44
GM3 Axle Rear 3.45
GM4 Axle Rear 3.67
GM5 Axle Rear 3.89
GM6 Axle Rear 4.22
GM7 Axle Rear 3.68
GM8 Axle Rear 2.56
GN9 Axle Rear 4.11
GS1 Axle Rear 2.73
GS3 Axle Rear 3.73
GS4 Axle Rear 3.70
GS5 Axle Rear 4.11
GS6 Axle Rear 4.56
GS8 Axle Rear 3.94
GT1 Axle Rear 2.56
GT2 Axle Rear 2.29
GT4 Axle Rear (Dup of 5X1) 3.73
GT5 Axle Rear (Dup of GT8) 4.10
GT7 Axle Rear 3.33
GT8 Axle Rear (Dup of GT5) 4.10
GU1 Axle Rear 2.41
GU2 Axle Rear 2.73
GU3 Axle Rear 2.93
GU4 Axle Rear 3.08
GU5 Axle Rear 3.23
GU6 Axle Rear 3.42
GU7 Axle Rear 2.77
GU8 Axle Rear 3.90
GU9 Axle Rear 3.91
GV0 Axle Rear 3.55
GV1 Axle Rear 2.73
GV2 Axle Rear 5.83
GV3 Axle Rear 3.08
GV4 Axle Rear 3.36
GV5 Axle Rear 3.55
GV7 Axle Rear 4.11
GV8 Axle Rear 2.72
GV9 Axle Rear 4.25
GW2 Axle Rear 2.56
GW3 Axle Rear 2.56
GW4 Axle Rear 3.31
GW5 Axle Rear 2.73
GW6 Axle Rear 3.27
GW8 Axle Rear 4.10
GW9 Axle Rear (Dup of GU3) 2.93
GX1 Axle Rear 3.70
GX2 Axle Rear 3.07
GX3 Transaxle Final Drive 3.33
GX4 Axle Rear 3.75
GX5 Axle Rear 4.09
GX6 Axle Rear 3.53
GX8 Transaxle Final Drive 3.74
GY2 Axle Rear 3.31
GY3 Transaxle Final Drive 4.29
GY4 Axle Rear 4.53
GY5 Axle Front 3.65
GY7 Transaxle Final Drive 4.18
GY9 Axle Rear 4.31
GYS Transaxle Final Drive 3.65
H01 Axle Rear 3.07
H04 Axle Rear, Single Speed 4.11
H05 Axle Rear 3.73
H12 Axle Rear, 21000 Lbs, Eaton 21065S, Single Speed
H42 Axle Rear 6.17
H43 Axle Rear 5.43
HA3 Axle Rear, Single Speed 5.29
HC4 Axle Rear 4.56
HC7 Axle Rear, 7500 Lbs, Single Speed 2.38
HC8 Axle Rear, Single Speed, Truck 3.21
HC9 Axle Rear 5.13
HE3 Axle Rear, 3500 Lbs, Single Speed 3.07
HE4 Axle Rear 3.40
HF7 Axle Rear, 10000 Lbs, Dana 70, Single 4.56
HF8 Axle Rear 4.88
HJ1 Axle Rear 4.55
HJ2 Axle Rear 5.86
HJ3 Axle Rear 4.75
HJ4 Axle Rear 6.50
HJ5 Axle Rear 5.57
HJ6 Axle Rear 4.78
HJ7 Axle Rear 4.88
HK1 Axle Rear 2.87
HK3 Axle Rear 6.14
HK9 Axle Rear 10000 Lbs, Single Spd 5.86
HO4 Axle Rear 4.11
HO6 Axle Rear 4.63

GMC Canada 2009-2014

Check Owners Manual



Truck Classifications Based on GVWR

FHWA - Federal Highway Admin

EPA - Environamental Protection Agency

GVWR (lbs) Vehicle Class
<6000 Class 1
10000 Class 2
14000 Class 3
16000 Class 4
19500 Class 5
26000 Class 6
33000 Class 7
>33000 Class 8