In 2020 I replaced my steering box as I had the same slop in the steering everyone seems to develop over time. When I did I also replaced the pitman arm. The part number was stamped on the old one, YC35-3590-AB and was about 9.5 inches long. I was told that that part number was superseded to 4C3Z-3590-DA, which is what I bought and installed. I noticed, however, the superseded part was shorter than the original, by a few inches and it had a bend in it despite the original being nearly flat. Nevertheless, I figured Ford engineers knew what they were doing and I installed the new shorter arm. My slop was cured but I did notice my turning radius increased pretty dramatically. I assumed it was due to the shorter arm and eventually got used to it. Fast forward to today when I parked the truck and left the wheels turned all the way to the left. I happened to look at the wheels and I could see the end link that attaches to the pitman arm was hitting against the large bolt that attaches the track bar to the bracket. It must have been hitting for some time because the bolt has a dent in it. Anyone else experience this? Thoughts on resolving it? I figure this is definitely causing the issue with the turning radius increase. I'd prefer not to install the original longer arm but other than grinding down the bolt a little to allow the end link to pass it I'm not sure I have another solution. See below (never mind the excess grease):

 

After searching around a little, I believe the correct number you should have been sold was the YC3Z-3590-DA.

 

I ran across mismatching pitman arms vs box install on ,y 2019 f-450.....the explanation for the exceptions was related to the electronic options vs not. My truck has some of the electronic options and ford actually down graded my pitman arm during build to an f-250 on.

 

Agreed, however....
And that is the part number I bought and installed. See the confusion I'm having and hence this post, lol.

 

I also notices something from your part number, that is listed for Twin I Beam which I do not have, I have mono beam which when researched is part number 4C3Z-3590-CA. I'll have to research the length but it seems that one letter may be the problem and it caused me to put the wrong part on.

 

The confusion continues....so today I ordered and picked up a 4C3Z-3590-CA from Ford, which shows its for a mono beam (as my truck is). I took my old oe pitman arm with me into the parts department. The oe and the new CA part are different sizes, maybe about half to 3/4 inch difference the CA being shorter. The CA is longer than the DA which is what I have incorrectly installed. Now my decision is 1) put the oe back on and keep using a pitman arm that has over 275k on it or 2) install the new CA arm and hope it clears the track arm bolt and reduces my turning radius to where it was previously. In any event I'm now in possession of 3 pitman arms and all 3 are different for the same truck... lol

 

Is there any problem with your original pitman arm? A pitman arm should last well beyond the life of a vehicle, assuming there is no wear on the splines or the drag link taper.

 

It appears to be in good order. I only replaced it originally because I was doing a new steering box and power steering pump, I wanted to go with all new stuff so I could eliminate the steering slop I was experiencing. I was curious if it was a wear item at all. If not, I suppose it could go back in.

 

yep a pitman arm has no wear points really. one end should be tapered splines and a tapered smooth bore on other end. wear points are the ball joints of the draglink.
now if for some reason the balljoint nut or sector shaft nut backed off then the tapers could become damaged but thats altogether different than normal wear.
you should of reused the original arm ,assuming the splines and taper was still good

 

Just an update on this for anyone interested. I swapped out the wrong arm with my original longest one and all is right in the world again, its crazy how much it affected the turning radius. Here is a picture of all three arms, part numbers and their total lengths:


Left to right:

YC35-3590-AB - 9.5 inches - this was installed originally in 2001 when the truck was built, arm is practically flat, for mono beam

4C34-3590-CA - 8.5 inches - this part is the superseded part to the above, both ends have a very slight bend, for mono beam trucks

4C34-3590-DA - 8 inches - this is for twin I beam trucks, both ends have a significant bend, will fit but causes the end link to hit the bolt head for the track bar at a hard left turn severely impacting turning radius.

 

Great update.

do these have 3 key splines or 1?

also, it should be know to all that for duallys until very recent, ford used a 1 key splines unsung a beefed up arm…..then….they went back to 3 key splines on models that have electronics in their steering (steer assist, lane keeping, etc)

 

I believe it was four actually.