whats the difference between 2wd and 4wd steering box - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Sweet72 · 08-14-2006, 06:54 AM

These are the NAPA power steering gears for 1972 trucks I found on their website. According to them the 2wd and 4wd PS gears are different. The only difference I can see in the specs below is the # of turns lock to lock. I have a 1980 PS box from a 2WD on my '72, and it is real responsive and improved the steering greatly over the manual box. I am using a '72 PS pump and had to make a special high pressure line with the metric O-ring fittings on the gear box end. I'm sure someone on the board can give you a better answer to your question about the turn radius...Good luck, Sam.

4WD
part no. NSP277502
# of Mounting Holes:4
# of Turns Lock to Lock:3 1/3 - 4 1/4
Input Shaft Diameter:13/16"
Line Thread Size:11/16x18; 5/8x18
Output Shaft Diameter:1.25"
Type of Hose Ports:Tube Seat

2WD
part no. NSP277501
# of Mounting Holes:4
# of Turns Lock to Lock:3 1/3 - 4 1/8
Input Shaft Diameter:13/16"
Line Thread Size:11/16x18; 5/8x18
Output Shaft Diameter:1.25"
Type of Hose Ports:Tube Seat

Livrat · 08-14-2006, 10:12 AM

The 2WD and 4ED boxes have different sector shafts. the 2WD ones are tapered splined and 4WD have a straight splined shaft with a "pinch bolt" to hold on the pitman arm.. they will bolt up the same the lines are the same but unless you do some serious mofifications they are not interchangable. In either 80 or 81 they used an "O" ring fitting for the hoses instead of an "inverted flare" other than that they are physically the same.

08-14-2006, 06:54 AM	#1
Sweet72 Registered User Join Date: Nov 2003 Location: Alexandria, VA Posts: 1,534	Re: whats the difference between 2wd and 4wd steering box These are the NAPA power steering gears for 1972 trucks I found on their website. According to them the 2wd and 4wd PS gears are different. The only difference I can see in the specs below is the # of turns lock to lock. I have a 1980 PS box from a 2WD on my '72, and it is real responsive and improved the steering greatly over the manual box. I am using a '72 PS pump and had to make a special high pressure line with the metric O-ring fittings on the gear box end. I'm sure someone on the board can give you a better answer to your question about the turn radius...Good luck, Sam. 4WD part no. NSP277502 # of Mounting Holes:4 # of Turns Lock to Lock:3 1/3 - 4 1/4 Input Shaft Diameter:13/16" Line Thread Size:11/16x18; 5/8x18 Output Shaft Diameter:1.25" Type of Hose Ports:Tube Seat 2WD part no. NSP277501 # of Mounting Holes:4 # of Turns Lock to Lock:3 1/3 - 4 1/8 Input Shaft Diameter:13/16" Line Thread Size:11/16x18; 5/8x18 Output Shaft Diameter:1.25" Type of Hose Ports:Tube Seat __________________ '72 GMC SWB C1500 Custom, frame-off in progress. 383 SBC, 9:1CR, Comp Cams XE262H, Scat internal balanced crank, Eagle SIR 6" rods, Keith Black dish pistons, Dart Iron Eagle 72/180 heads, Weiand Stealth intake, Stewart stage I water pump, Holley 4bbl vac sec, TH350 with B&M Shift Improver Kit. 12 bolt positraction. Last edited by Sweet72; 08-14-2006 at 07:14 AM. Reason: Additional info

08-14-2006, 10:12 AM	#2
Livrat Member #1049 Join Date: Jun 2000 Location: Troy Montana Posts: 3,940	Re: whats the difference between 2wd and 4wd steering box The 2WD and 4ED boxes have different sector shafts. the 2WD ones are tapered splined and 4WD have a straight splined shaft with a "pinch bolt" to hold on the pitman arm.. they will bolt up the same the lines are the same but unless you do some serious mofifications they are not interchangable. In either 80 or 81 they used an "O" ring fitting for the hoses instead of an "inverted flare" other than that they are physically the same.



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