Thanks for putting up with me. I'm definitely no mechanic and this site has been a great help for me. Thanks in advance, and apologies if this is a common topic that I failed to find.

So for a couple weeks now I've been experience what I believe to be a bad u-joint issue. "Thunking" when I throw it into drive or reverse, and occasionally park. Also, it tends to "whir" a little louder than I'm used to. Not to mention, there has also been a little bit more vibrating when driving, and I'm assuming this can be a cause.

Anyways, my question is this -

In a 2003 4.6L F150 XL Heritage (Reg Cab), what size are the OEM U-joints? I noticed I have two options - "1-1/16, and "1-3/16. Which one is correct? Would either work, and if so, what is recommended?

Thanks again, I'd really love to get this resolved.

 

I would get under there and try to wiggle the drive shaft to see if the U-joints are good. In both my brother's truck and my truck we had a whirring sound, and his was thumping in reverse hard, turned out to be a bad pinion for me, and his whole rear diff was shot. If the drive shaft moves quite a lot and it's not at the U-joints but where it goes into the rear diff, you may have differential problems.

As far as the U-joint, I think it is 1-1/16". Not my area though, I'd get more conformation on that.

 

Have you greased them? If not i'd start with that.

 

Thanks for the quick replies - much appreciated!

I have tried moving the driveshaft by hand, but with no luck - it's tight! But I have heard that when moving there is more give to it, and can shake and "whir" only when driving. I don't know if that's true, but if that is the case, I guess it doesn't explain the "thunking," though I don't know what else would cause that sound.

As far as greasing, how thorough are we talking? Would silicone spray work? Or should I remove the drive shaft and give it a real good greasing that way?

Also, I guess I just need to know if the U-Joints are 1330, or 1350 "size" or whatever that number refers to - model maybe?

Anyways, I appreciate the responses and thanks for putting up with me. Just starting to get into this kind of stuff, so I'm green as can be.

Thanks.

 

Just a thought, the thump could be because of a bad slip yoke, you may just need to grease it.

If you have stock U-joints, they did not come with grease fittings, so you can't grease them. To check, just look in the elbows of the U-joint if the makes sense, and there will be a grease fitting if you have one.

Is your truck 4wd? I think that would go into the sizing.

 

No grease fittings, so that's a no go.

Also, it is indeed a 4 wheel drive truck. Would that bump it up to "1-3/16?

 

From what I am seeing, no. I am going to say you need a 1-1/16".

Tired of messing around with this URL stuff, every time I put it in it just takes you to the home page..... go to jcwhitney.com and put /moog-u-joint/p3090547.jcwx?skuId=9494420&filterid=d18911y2003g8 8j1 at the end in the URL.