Hi All, new to this, but looking for some help. This maybe already out there, but I couldn't find it. I have a 97 F350 Powerstroke and have been working on replacing front end stuff. Recently did tie rods, center link, and steering gear. Working on front leaf springs and track bar, so I can finally get this thing properly aligned. While under it I noticed the front axles on both sides will move slightly back and forth or straight in and out. There is no wobble or side-to-side play in them at all, they seem tight from that perspective. Lockers will engage just fine. Is this back and forth movement okay? Dude at alignment place said no, but not sure how much I trust him. He we thinking that the inner and outer locknuts might be loose, but I’m not sure they would or should fully seat against the axle. I pulled apart both sides to get a better look at the locknuts, but nothing obvious loose or broken. Both sides do it, maybe ¼ inch. I put a couple pics to hopefully explain it a little better. Any thoughts or advise are appreciated. Thanks!

 

They are fine. “Maybe a quarter inch” sounds like very little movement. The axle shelf itself essentially rides in place. The locknuts secure the hub not the axle shaft itself. When you had the locking hubs off did you move the shaft? If you didn’t, take a look. It does not support weight and it can’t really go anywhere if properly assembled. The hub flange and the axle tube prevent it from going anywhere.

I did check mine and it doesn’t really move but I do have a fresh build on it with new axle seals so it is pretty tight. I remember checking mine during normal servicing and remember so negligible movement.

I would get some grease in those upper ball joints. In the pics, they look pretty dry

 

It could be more than a quarter inch, I was thinking this was right but looking back at my video it may be more than that. It didn't seem like enough to be worried about but maybe it is. I did move the shaft while I had the hub off and that was what kicked off my thought process for this maybe not being an issue. It is old and likely never replaced, so I expect more play in it but if I don't have to replace it now I'd be happier not to. That's another dollar for another day.

Thanks for the recommendation on the ball joints, I will certainly do that.

 

Did you ever determine why they are loose? I have the same issue. I disassembled my hub/Axel assembly and found no snap ring. Both side have this 1/4 to 1/2 inch movement back and forth. I would imagine the snap ring would keep the Axel from moving but my Axel has no groove for a snap ring to seat. I think they go near thee end of the Axel towards the hub. ?

 

I did not figure out why they are loose. Based on the response I got I just took that as them being okay and moved on. I'm pretty much continually working on this thing, so I hadn't really thought about it again. Unfortunately I don't have any pictures from when I removed the hub assembly and looked so I can't recall a snap ring/location. I would have no problem taking mine back apart and getting some pictures for you but unfortunately a buddy took my jack stands and hasn't given them back yet. Currently the pickup sits in the garage as I redo up-pipes again so this would be easy enough to check. If someone else doesn't answer your question and I get my stands back I'd be happy to take a look for you. Otherwise sorry I couldn't be more help.

 

Mine does not have snap rings. Some do and I cannot remember the difference as to why some have them and some don’t. Maybe it has something to do with manual vs auto hubs from the factory??

My brother’s had the snap rings but I cannot remember seeing anything different that helped me understand the difference between his and mine. Both are 97 model trucks.

Again, some movement of the axle shaft does not necessarily indicate a problem

 

My bet is wear in the ring gear or Spider gears . should be normal . Moving from forward to reverse the axles should shift from side to side based on simply the angle of all the gears .

 

There's not much positive retention in the front axleshafts. They don't carry any load and just transmit torque. Inner end is splines inside the differential's side gears, outer end is splines inside the hubs. Axleshaft can move in or out on these splines, while hubs and differential side gears / carrier / ring gear stay in place. Remove hub, and axleshaft pulls out. Basically, the axleshaft is VERY free-floating. Not an engineer, but I suspect that is to allow the axleshaft to "seek" the neutral in/out location where the U-joint centerline meets the steering axis... the line between upper and lower balljoints. That should be the point of best alignment, and least wear for the U-joints and splines. So the "slop" is "allow enough play to let it self-align, but keep it from falling out".

Contrast with the axleshaft in our full-floating rear differential. Inner end is splined into the side gears, but outer end is bolted to the rotating hub. When assembled, the wheel bearings locate the hub, which locates the axleshaft, so the axleshaft cannot move side-to-side.

Compare also with the CV axles of a front-drive car. There, the axles and CV joints have to deal with much more misalignment suspension movement as well as steering angle. Those splines have much more in-and-out movement, but usually also have clips or some other means to keep the splines from sliding all the way to one side and falling off the other end.

 

Thanks for the responses. When I pulled out the driver's side Axle I noticed the wheel end of the axle was floppy for lack of a better term. The u joints had no stiffness to them. Would this warrant u joint replacement? Upon visual inspection the u joint looked fine but I heard that they should have a little stiffness to them. Maybe like the difference between a new ball joint and a worn out ball joint. ?

 

new ujoints will feel stiff because the seals are new

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