The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Part # for correct front U joints at wheels

Toro · 08-04-2023, 04:29 PM

From TorqueKing 4x4:

GM used at least three different axle shaft configurations for 1969-1972 Dana 44 front axles. 1969 Blazer inner axle shafts are 1" shorter than 1970-1972 axles. The outer axle shaft for 1969-1970 drum brake axles are 1/10" shorter than those used on 1971-1972 disc brake axles. In mid-year 1972, the axle u-joint size was increased from 1310WJ series (1-1/16" cups) to 1350WJ series (1-3/16" cups) although the lengths remained the same. General Motors used an small Spicer 1310WJ series axle universal joint with tiny 1-1/16" diameter u-joint cups for the 1969 to 1972 on Dana 44 open knuckle front axles. The physical dimensions of this series of axle joint means is marginal for full size truck applications which is why it was replaced by Spicer 1350WJ series medium size axle u-joints with 1-3/16" cups during the 1972 model year

So that explains why I've been seeing two separate ones listed for 1972 model year. I'm not sure when "mid-year" it was changed. My Blazer build date is early, September 1971. I guess I'll be measuring tonight to see which one it is. I also wondered if there is a stamp on the tube that might be different before and after the change.

08-04-2023, 04:29 PM	#6
Toro Registered User Join Date: Nov 2018 Location: Huntsville, AL Posts: 339	Re: Part # for correct front U joints at wheels From TorqueKing 4x4: GM used at least three different axle shaft configurations for 1969-1972 Dana 44 front axles. 1969 Blazer inner axle shafts are 1" shorter than 1970-1972 axles. The outer axle shaft for 1969-1970 drum brake axles are 1/10" shorter than those used on 1971-1972 disc brake axles. In mid-year 1972, the axle u-joint size was increased from 1310WJ series (1-1/16" cups) to 1350WJ series (1-3/16" cups) although the lengths remained the same. General Motors used an small Spicer 1310WJ series axle universal joint with tiny 1-1/16" diameter u-joint cups for the 1969 to 1972 on Dana 44 open knuckle front axles. The physical dimensions of this series of axle joint means is marginal for full size truck applications which is why it was replaced by Spicer 1350WJ series medium size axle u-joints with 1-3/16" cups during the 1972 model year So that explains why I've been seeing two separate ones listed for 1972 model year. I'm not sure when "mid-year" it was changed. My Blazer build date is early, September 1971. I guess I'll be measuring tonight to see which one it is. I also wondered if there is a stamp on the tube that might be different before and after the change.