I think it's coming from the rear axle. It's only when your on the throttle and between 20 and 80 km's. If you let up the throttle at any point in between those speeds it goes totally away. Get on the throttle again and it comes back.At highway speeds, it either siliences or is just not loud enough to hear. It's an 01' F250 SD. 4X4 5.4L auto. The sound is related to speed because it seems to wind up with momentum. I mean it does not coincide with engine rpm. I bought this truck used with a cracked manifold and did'nt notice it until i fixed the exaust. When i started looking around i noticed that there was too much play in the opinion bearings so i replaced them.. When i took the cover off and spun the yoke, the pinion gear would move outside its axes before it spun. I put all new pinion bearings in it but it never change the noise.

Anyone got any help? Thanks

 

Welcome to FTE. You will like it here, a lot of good folks with a lot of knowledge. Don't be shy with questions, and feel free to chime in whenever you want.

How long have you had the truck? Could it be tire noise? Wheel bearings? U-joints usually squeak when they start to go bad. Just throwing out some possibilities. Actually, just re-read your post, and letting up on the throttle the noise goes away should eliminate tire noise as a possibility.

 

Are you sure it's coming from the rear end and not the front? How many miles you have on the truck. The front unit bearing are know to fail and this maybe the sound you hear.

 

Have you tried checking the rear driveshaft slip yoke? When the grease dries up, it will give some free play. Enough to set off a resonance sound that can be heard as well as felt from the driver seat.

 

Do you have a hanger bearing in the middle of the driveshaft?

When you did the pinion bearings, were the diff carrier bearings good?

 

I'm sorry, i left out some info. I've also replaced the four u-joints(front and rear). It does'nt have a mid driveshaft bearing. I really think it's at the rear because what in the front would have to do with letting off the throttle? I will have to check the driveshaft slip yoke, I did'nt think that could be my problem.. As for the diff carrier bearings(the ones on either side of the crown) everything seemed tight.. The new pinion bearings took the slack out of the pinion but i probably could of got the same results with a crank on the yoke nut. Just to reiterate. it is a direct result of motion and speed, and can almost be felt in the cab floor.

I'm kinda stumped on this one but the response has been terrific. With this much interest, I should be fine.

 

If it were me, and really couldn't locate the noise, I'd pull the rear axles and the rear driveshaft, put it in 4x4 and take it for a drive. That would totally eliminate the rear differential.

And it's fun peeling out with the front wheels

 

Silly you! Without the rear axles it would be dragging around on the rear bumper

 

I suspect that your gear pattern is weak or damaged if the pinion bearings were loose. If you get a whining noise with throttle then it gets quiet under coast, the gears on the drive side are not meshing well. Do you know how to check the pattern? I would take the cover back off and see if it has a decent pattern, or any abnormal wear on the gear face. The carrier bearings being "tight" doesn't really mean anything. Debris that took out the pinion bearings could have damaged the carrier bearings too. Did you inspect them for any pitting or discoloration?

 

Sorry, not sure how to check the pattern. Actually, don't really know what it is. Could you explain?

 

Krewat's right , In that you can with the semi floating rear diff. pull the axels from the hubs for many reasons leaving the hub bearings and everything else, but for a drive? he he! I'd have to block off the hubs somehow.
Sure sounds like gear mesh, with pinion bearings reset (or not)? IMO.

 

Krewats set up many differentials, as he has mentioned here before. He may be able to direct you to a good source for setup instructions. It seems all the new diffs entertain a crush collar in pinion set up ( Aside from the DRW rigs/I,m jealous of for the diff.). They have to be set to a preload, that sets up a wear pattern on the ring. I my self have only been hands on with an older 10 bolt Cheby. You might try PMing(personal messaging) him on this topic. Also surf this site in search mode(search), I have had loads of answers come from some really old threads. Best of luck.

 

I must not have pm privliges. I can't find a pm prompt.

 

Not enough posts yet but he's the Moderator and will check on this thread soon enough. Especially since he posted in it. I'm with aldridgec on this one.

 

Hey, it's Chris to you. Figure since I'm a supporter now, I can be more personal!

I'll try and find a good site online to show you different patterns and what they mean. The crush sleeve doesn't have anything to do with the pattern, just the preload. The shims under the pinion head bearing as well as backlash, which is the adjustment of the carrier shims, determine the pattern. However, from the factory they use solid shims that are machined to the right specs, so they are not adjustable.

You can check the pattern with some moly grease, but because it is dark it will be hard to see the pattern. I use marking compound, some use a white lithium grease. I've never gotten great results with the white litium type grease. I usually take the marking compound supplied in master install sets and mix it with a little gear lube. That makes a great clear pattern usually. Coat a few teeth of the ring gear with the marking compound and turn the gear so it meshes with the pinion in that spot. Run it back and forth a few times so you can see how the teeth are wearing/meshing. I'm uploading some pictures so you can see what it looks like.

Here they are. The first one is a Sterling 10.5, but the picture is out of focus. you get the gist of a decent pattern on the coast side. The second is a good picture of the drive side of a GM 14 Bolt.





There are many resources on the web showing installation instructions. Most of the major axle parts distributors have them on their respective sites. Here are a few that you get from Googling.

http://www.google.com/search?hl=en&q...earch&aq=f&oq=

You may be able to tell something just by removing the cover. So you can just check into that first.