Done a lot of searching posts, and have not found a solid answer to this problem, but if I missed something and you know where it is, let me know!

The issue is with my 2000 F350 crew longbed V10. Other than a BTS trans put in a little over a year ago, and FoMoCo motorsports headers, the whole truck is bone stock. Oh, it has that fantastic auto-hub thing with the fake locking hubs and the little switch on the dash (I'd love to convert it to a manual shifter...anyone done that yet?). 174k on chassis, so things need to be done, 40k on engine, 3k on BTS 4r100.

Yesterday I was running around town, made a stop, and when I started moving again got a loud grinding from the front axle. Thought maybe I'd picked up a rock in a caliper or something, so I jumped out and checked everything, no joy. Moved forward, there it is again. No vibration, but loud enough (or telegraphing enough) to hear clearly in the cab. Let the truck roll forward, popped in to neutral, noise fades away. Back in to drive, there it is. So, now I know it's trans/t-case/driveshaft/related. I recently put new vacuum lines in, checked all the connections, and pulled, cleaned and lubed the hubs.

And since the trans is a nearly new BTS (if you don't have one and you have the money, get one) that is working just find, I'm narrowing the search to the hubs, drive shaft, t-case.

Get home (noise abates above 30mph, or everything else drowns it out), crawl under, and find the front driveshaft is locked. Ok, stuck hub? Pull out both the fake locking hubs, and now the shaft turns. I can turn each front axle by hand at the u-joint, and I kinda hear a faint grinding on the right side (will bad needles make noise only under a load from the trans and not coasting in neutral?), and when I swing the drive shaft around the left axle moves, right doesn't, etc etc.

I'm going to pull the drive shaft today and check the U joints, and drive a bit to see if the noise is still there, but I am thinking I might have some bad needles on the pax side axle...anyone else think that, or have a different suggestion?

Thanks for any help, thoughts, ideas, etc.

 

Id say you have it narrowed down. If the front hubs are original they most likely need replacing...same for the front outer U-Joints. Use Spicer driveline parts steer clear of chineasium!

 

Haven't had a chance to pull the driveshaft yet, but that's what I'm leaning towards, the hub. And yeah, it's time, not only for hubs and axle U-joints, but for the drive shaft(s), too.

The noise under load threw me for a minute, but serviceable or press-in sealed units can do the same thing, be going bad and only make noise in a turn (which is, of course, a loaded condition), so there you go.

Gonna have to head out and get a star socket for the bolts on the t-case output flange...anyone know offhand if those are SAE or Metric?

 

Imagine that...you do a bit of research and there's the answer...12mm! So for anyone else looking for the size of those 12pt bolts on the t-case output flanges, they are indeed 12mm.

 

Thanks for following up. Please follow up with what you found out to be faulty. Always nice to close the loop for future searches(ers)