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

**hilljob26** · 08-13-2006, 10:20 PM

i was wandering if a 2wd steering box was any differnet from a 4x4.i currently have a 1980 blazer box on my 72 and it doesn't seem to turn very sharp and some have told me that 2wd have a tighter turning radius.is this true,and ifso,does anybody have a 2wd from that style seems how the lines are different,they have a little straight part that comes down unlike the older ones.thanx...mike

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.

**hilljob26** · 08-14-2006, 02:02 PM

yeah,im using a 72 pump as well,and have the o-ring type hoses w/ my 80's box,so what mods do i have to do to get the pitman arm to fit right,if i use a 2wd box from an 80's or so truck

see ten · 08-14-2006, 04:18 PM

Whoa nelly!!!!! One box is designed to turn the pitman arm from left to right the other box turns the pitman arm from front to back. Installing a 2wd box on a 4x4 is what people do when they go to crossover steering conversion. Aside from that I am pretty sure it is a no go situation. Are you just trying to get fewer turns lock to lock or is your turning radius just to wide? I know some people have trouble turning after installing a lift and larger tires. Has your steering arm or draglink already been changed? I am pretty sure that there are steering boxes available that can cut down the lock to lock #s.

08-13-2006, 10:20 PM	#1
hilljob26 Registered User Join Date: Dec 2004 Location: Gypsum Kansas 67448 Posts: 1,681	whats the difference between 2wd and 4wd steering box i was wandering if a 2wd steering box was any differnet from a 4x4.i currently have a 1980 blazer box on my 72 and it doesn't seem to turn very sharp and some have told me that 2wd have a tighter turning radius.is this true,and ifso,does anybody have a 2wd from that style seems how the lines are different,they have a little straight part that comes down unlike the older ones.thanx...mike __________________ 21 2500hd duramax 58 apache HILLJOB GRAPHIX--for all your graphic needs My build thread http://67-72chevytrucks.com/vboard/s...d.php?t=542497 LS ENGINE SWAP INFORMATION THREAD http://67-72chevytrucks.com/vboard/s...d.php?t=377348 4l60 to an NP205 http://67-72chevytrucks.com/vboard/s...43#post3697343

08-14-2006, 06:54 AM	#2
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	#3
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.

08-14-2006, 02:02 PM	#4
hilljob26 Registered User Join Date: Dec 2004 Location: Gypsum Kansas 67448 Posts: 1,681	Re: whats the difference between 2wd and 4wd steering box yeah,im using a 72 pump as well,and have the o-ring type hoses w/ my 80's box,so what mods do i have to do to get the pitman arm to fit right,if i use a 2wd box from an 80's or so truck __________________ 21 2500hd duramax 58 apache HILLJOB GRAPHIX--for all your graphic needs My build thread http://67-72chevytrucks.com/vboard/s...d.php?t=542497 LS ENGINE SWAP INFORMATION THREAD http://67-72chevytrucks.com/vboard/s...d.php?t=377348 4l60 to an NP205 http://67-72chevytrucks.com/vboard/s...43#post3697343

08-14-2006, 04:18 PM	#5
see ten WTB this ad Join Date: Sep 2004 Location: Lafayette Georgia Posts: 5,074	Re: whats the difference between 2wd and 4wd steering box Whoa nelly!!!!! One box is designed to turn the pitman arm from left to right the other box turns the pitman arm from front to back. Installing a 2wd box on a 4x4 is what people do when they go to crossover steering conversion. Aside from that I am pretty sure it is a no go situation. Are you just trying to get fewer turns lock to lock or is your turning radius just to wide? I know some people have trouble turning after installing a lift and larger tires. Has your steering arm or draglink already been changed? I am pretty sure that there are steering boxes available that can cut down the lock to lock #s.



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