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F250 Steering gear box upgrade with 2016 6.7 gear box

15373 Views 58 Replies 24 Participants Last post by  PasadenaMike626
This topic has been brought up a few times and I noticed many questions went unanswered. I wanted to create a new post that would answer any questions anyone had when it came to swapping out the original 6.0 steering gear with a newer 6.7 steering gear. My original steering gear was tired and I was frustrated with a loose steering while driving and hard steering while moving slow. After some reading, I decided to go with an OEM gear box from Ford out of a 2016MY truck (2011-2016 might be the same PN I just used 2016 because I also own a 2016). The gear box swapped right over with minimal modifications (if one would even call them that) on my 2006 F250 4WD 6.0L.

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Below are the Ford Part numbers you will need to make this happen
Steering Gear- GC3Z-3504-E (2016 6.7 F250 4WD gear box) $627.58 (-$200 core)
Steering shaft- 6C3Z-3B676-B (2006-2007 F450 steering shaft) $131.03
Steering gear bolts (X3)- W713909-S439 (you have to buy 4 of them as there are 4 to every pack) $16.02
16mm or 5/8 drill bit

The steering shaft needs to be replaced because the input shaft to the steering gear is different. The original steering gear had a splined shaft while the new style steering gear had a 3 faced shaft. I did not feel like modifying my steering shaft so I just purchased a new one. I did notice the coupler ends were available used on ebay but that would require modification of the shaft the price was very comparable to a new shaft. The F450 in 2006-2007 has the same style steering input shaft as the newer trucks (2011-2016).
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Steering column coupler (exactly the same)
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Left- Original splined gear box coupler Vs. Right- New style coupler.

  • Replacement goes as follows... Make sure your steering wheel is straight and use a strap or something comparable to keep steering wheel straight.
  • Remove steering damper from drag link.
  • Remove drag link from pitman arm.
  • Remove Steering shaft from steering column and steering gear, remove shaft coupler plastic housing from shaft.
  • Disconnect steering oil lines
  • Remove steering gear box- On a stock truck, no need to jack up vehicle, steering gear will come right out.
  • Remove pitman arm from original steering gear. (it will swap right over to new steering gear box)
  • Install pitman arm on new steering gear in the same position. The pitman arm can only be clocked three ways so its not easy to Fk up. When purchasing a new steering gear, they come clocked straight and should be marked for reference.
  • Drill outer holes on frame out with a 5/8 drill bit, you will not need to drill inner side of the frame. You will notice that not much material is actually removed. Clean holes.
  • Remove rear sway-bar mount bolt and self retaining nut. You will need to grind the bolt and nut down about 1/8" for the steering gear to clear. Reinstall nut and bolt.
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  • Install new steering gear and torque bolts to
  • I didn't take a picture of the plastic coupler guard, but you will need to trim some plastic where it slides over the tabs on the new steering gear. You will notice plastic mold marks on the OEM coupler guard, follow those lines and cut about 3/8" deeper.
  • Install new steering shaft with coupler guard. (you may notice that you have to turn steering shaft 90 degrees to the left- that's ok and will be rectified after job is done as described below).
  • Reinstall steering lines- You will need to slightly bend steering lines to get them to fit, do not kink the lines. Remember to replace the vinyl washer on the return line if it is worn. Good idea to replace the high pressure o-ring as well. Make sure lines are not rubbing. I covered my return line in split loom for extra protection.
  • At this point with the drag link still removed and everything reassembled up top, you can flush and bleed the hyrdo-boost system (I used the recommended OEM Ford Mercon V about 4 quarts).
  • Reconnect drag link and steering damper.
  • Make sure to bleed out system if you did not flush system. Jack front end up and turn steering wheel left to right a few times while applying and releasing the brake multiple times.
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  • You should be ready to test, here's a picture of the new steering gear installed. The fit is a little tight but I dont see that causing any problems. The Radiator hoses are well protected from rubbing with split loom from the factory.
  • You may have to adjust your drag link like I did, adjust your drag link while keeping your steering wheel centered in its original position. I just had my truck aligned before changing the steering gear so I know the toe adjustment was good, I just had to adjust my drag link so that my steering wheel was straight along with my wheels. I noticed both of my wheels were turned slightly to the right while my steering wheel was clock 90 degree's to the left (remember I had to turn steering shaft 90 degrees to the left in order to slide steering shaft onto steering gear input shaft). I also noticed my wheels would not turn completely to the left. After adjusting the drag link so that my wheels and steering wheel was straight- everything was good to go. You could always go get an alignment after, completing the job if you're due for one.
You may notice I didn't post torque specs, that's because I looked them up as I went along with the install. If someone would like to post the required torque specs, that would be great.

My truck now feels like cutting warm butter when turning and the steering slop is gone. I highly recommend this upgrade over the redhead overpriced steering gear. Hope this helps!

2016 steering gear box specs
Inlet Port Thread DiameterM18-1.50
Input Shaft Diameter0.73 Inch
Input Shaft Diameter18.542mm
Mounting Hole Quantity3
Outlet Port Thread DiameterM16-1.50
Output Shaft Diameter1.62 Inch
Output Shaft Diameter41mm
Total Turns Lock To Lock4

2006 steering gear box specs
Inlet Port Thread DiameterM18-1.50
Input Shaft Diameter0.75 Inch
Input Shaft Diameter19mm
Mounting Hole Quantity3
Outlet Port Thread DiameterM16-1.50
Output Shaft Diameter1.62 Inch
Output Shaft Diameter41mm
Total Turns Lock To Lock4


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I really enjoyed your post, but have been having a difficult time finding the lower steering shaft assembly 6C3Z-3B676-B. I can find the -A model but I don't know if that would actually work or not so is there another part number that would work in this case? The shaft is no longer available on FPG (discontinued) so I am looking for alternatives. Also, I wanted to confirm that for the bolts you need 4 packages of 4 bolts (total of 16 shaft bolts). You said that you could have swapped out the shaft ends with those for the F450 so I wanted to confirm that with you, and what those part number may be (if you know), if that was a direction I had to move in.

Any information you could give me would be greatly appreciated, and I thank you for all the time and effort that you have already put into this effort it is clear that many people have found it very useful.
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The steering shaft would work if it was removed from a 2006-2007 F450 or F550. You might be able to swap out steering shaft ends with a 2011+ I just have not confirmed. The only reason you will need a new shaft is to couple to the gear box, you might be able to get away with swapping the shaft end only if you can acquire the correct coupler. Other years may work I just haven't confirmed. As for the gear box bolts, QTY. 4 come in each pack. you just need to order QTY. 1 pack, you will only use three.
Thank you for the information, it has been very useful.

I'm currently in the process of doing this swap. I had to get a junk yard shaft. I paid $60 including shipping. Go on and search up criteria, it took me a second to find one but there out there.
Thank you, I was able to find the part as you described. I appreciate all of the assistance everyone has provided and will let everyone know how it ends up going.
Anyone find an alternative to that shaft? Can’t find one anywhere.
Contact (978) 458-6222, they had two available when I purchased mine from them. They might still have the second one available.

Thank you, I was able to find the part as you described. I appreciate all of the assistance everyone has provided and will let everyone know how it ends up going.
Just completed the upgrade, as has been pointed out here, finding the shaft was a bit of a challenge but I eventually found one. The difference is night and day, and the upgrade is well worth the time and effort to find the parts! There are times when driving it almost seems to be too effortlessly, no slop, smooth turns, and certainly much less effort than the previous steering box. This is absolutely one upgrade that anyone with an F250 should do immediately. Thank you @PasadenaMike626 for posting the outstanding information, great directions, and a great upgrade.
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