4x4 Technical Information

Lift kits required to fit larger size tires for full-size 1973-1991 Chevy Blazer/GMC Jimmy and 1973-1987 Chevy/GMC Pickup.

Tire Size = 31"     (no lift required)

Tire Size = 32"     (no lift required)

Tire Size = 33"     2" lift

Tire Size = 35"     4-6" lift

Tire Size = 36"     6" lift

Tire Size = 38"     6-8" lift

Tire Size = 39"     8" lift

Tire Size = 40"     9" lift

Tire Size = 42"     10-12" lift

Tire Size = 44"     12-14" lift

Lift kits required to fit larger size tires for full-size 1988-1998 Chevy/GMC Pickup and 1992-1999 Blazer/Tahoe and Jimmy/Yukon.

Tire Size = 31"     (no lift required)

Tire Size = 32"     2" lift

Tire Size = 33"     4" lift

Tire Size = 35"     6-8" lift     

Tire Size = 36"     8" lift

Tire Size = 38"     8-10" lift

Tire Size = 39"     10" lift

Tire Size = 40"     10-12" lift

Tire Size = 42"     12" lift

Tire Size = 44"     12-14" lift

Information coming soon for 1969-1972 Chevy Blazer/GMC Jimmy and 1967-1972 Chevy/GMC Pickup.

Transfer Case Info.

The following information is not set in stone. Be aware of the fact that people like to modify their trucks. Your truck, if it does not match anything on the charts below, maybe the product of someone's creativity or just one of those things...

Once you do figure out which transfer case you have, go to the Transfer Case Properties chart at the bottom of this page to find out about it.

 

CHEVY BLAZER TRANSFER CASE IDENTIFICATION

Years

Transmission Type

Transfer Case Model

Notes
1969-1973 Automatic NP205
1969-1974 Manual Spicer 20 NP205's also used
1973-1979 Automatic NP203
1975-1979 Manual NP205
1980-1991 All NP208
1992-1993 All NP241

GMC JIMMY TRANSFER CASE IDENTIFICATION

Years

Transmission Type

Transfer Case Model

Notes
1970-1972 Automatic NP205
1973-1979 All NP203
1973-1974 Automatic NP205 Optional
1975-1979 Automatic NP205
1980-1991 All NP208 NP241 also used

Transfer Case Properties

Transfer Case Model

4 Wheel Drive Mode

Drive

Low Gear Ratio
NP203 full-time chain drive 2.00:1
NP205 part-time gear drive 1.96:1
NP208 part-time chain drive 2.61:1
NP241 part-time chain drive 2.72:1
Spicer 20 part-time gear drive 2.03:1

Transmission Gear Ratios

 Transmission 

1st Gear

2nd Gear

3rd Gear

4th Gear
3-speed manual ('73-'80) 2.85 1.68 1.00 ----
M15 3-speed manual ('81-'84) 3.50 
Opt: 2.85/3.11		 1.68 1.00 ----
SM465 
4-speed manual		 6.55 3.58 1.70 1.00
TH350 3-speed automatic 2.52 1.52 1.00 ----
TH400 3-speed 
automatic		 2.48 1.48 1.00 ----
700-R4 4-speed 
automatic('82-on)		 3.06 1.63 1.00 0.70

 

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