hammdy

I was trying to track down some weird noises on my truck (creaks and clunks and what-not). I went to check the u joints and they appear fine, but when I grab the driveshaft it rotates a little bit and clunks. It looks like something is loose at the point at which the driveshaft goes into the diff. I don't really know how it's connected in there...splines? Could the splines be worn out if so?

hammdy

I'm gonna lube the splines and see what happens

torkum

Time to replace the ujoint?

cole_ford

Either Ujoints, or yeah, the splines are worn. And lubing it probably wont do much. I cant remember who I was talking to , but somebody on here had there whole driveshaft rebuilt because of the slight clunk. Ive been told by Ford to either lube it up every couple months, or have it rebuilt. But your slop in the drive shaft sounds like Ujoints

hammdy

it's not the u joints

hammdy

my most recent theory is that the pinion nut is loose. I'm going to take the driveshaft off tomorrow, drain the rear end and check it all out.

Good old Bill

The driveshaft is connected to the yoke via the u-joint. The yoke is splined to the pinion, doubt very much the movement is there. Now be advised there is backlash between the pinion and the ring gear, this can make a noise and be normal. Just be cautious, and don't get crazy spending money. Continue asking questions. Excellent help available here.

hammdy

Yeah I'm pretty sure the play is excessive backlash between the ring and pinion which is why I'm going to check and make sure the nut is properly tightened. The input seal is leaking anyway so it won't cost me more than $30 for oil and a seal.

cole_ford

wrong. oil is anywhere between 11 and 17 bucks a quart. the seal is about 15 and the new crush sleeve you need is gonna be about 3. Not to mention I hope you have a long cheater bar, cuz it takes A LOT to tighten the new crush sleeve. I need to change my pinion seal too cuz when I did bearings in the rear diff. We needed to pull the new pinion seal and tried to save it but it didnt last more than a month. And I really dont want to have to mess with the crush sleeve again so im gonna have a pro. do it. Not to mention I dont have the proper tools to get the exact backlash set.
And you wouldnt think that the backlash would be off unless you have something else going wrong. If youre gonna have the cover off, you may as well pull the carrier out and inspect all bearings. Just make sure everything goes back in the way it came out.

hammdy

I pulled the diff cover and the oil was clean and the gears looked good. Pulled off the driveshaft and checked the amount of torque required to rotate the pinion and it was 22 in-lb. So that was in spec, but you can grab the yoke and there is a lot of rotational free play in it, like there's too much backlash in the gears. But I checked my friends F150 and it was the same way and his doesn't make any noise. So I installed new u-joints just for the hell of it too. Noise is still there.