D60 Noise Driving Me Crazy

BigVan

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Hello all. I’m a long time lurker and learner but don’t post much on any platform.

Short of it, I have a loud high pitched whistle (not a bearing squeal) like noise and a low rumble from the rear differential (90% sure), but only at speeds over 65 and only on a very light throttle throttle. Nothing at lower speeds. Nothing accelerating and nothing while slowing down. No change with curves either side. Nothing feels hot after a 20 mile drive. No change with road surfaces. It’s a van so I know it’s a giant amplifier inside but it’s driving my dog and me insane. If I’m looking forward it’s loud and from the back/center, turn my head to listen and sort of it goes away. Details below.

91 E350, NA 7.3IDI
315 70R17
D60 rear and D60 Kingpin Front
3.54 gearing

Sometime last year the pinion nut worked itself loose in the middle of Canada heading down to New Mexico for work. The yoke actually came off at a stoplight and after removing the rear drive shaft and limping it to the nearest auto store with a parking lot patch job I was back on the road. I didn’t have an option to wait due to COVID regs. It made it here… then the pinion bearing cage came apart and locked up destroying everything in the process at about 50 miles an hour.

So I tore into it. Flushed the axle, replaced all bearings and races, installed a Yukon ring and pinion replaced U-joints with spicer lifetimes and took it for a drive. It started making noise again which I figured out was a pinion race that had moved about .003 due to not seating all the way. While changing the oil after around 500 miles, I noticed a slight wear (shiny) pattern on the ring gear so I tore into it again and replaced the pinion bearings and races.

My settings are below. The specs I used came from the Yukon install guide.
Runout max was .002
Backlash .007
Pinion rotational preload 22 inch pounds
Pinion nut 250 ft pounds (with red lock tite)
Drive and coast pattern ideal and checked in multiple spots.
Carrier preload was enough that I could barely start it and then had to seat it with deadblow. (Don’t have a case spreader)
All bolts torqued to spec.
Filled with a bottle of lsd additive and 85W gear oil.

Of note, maybe a separate issue but I borrowed a chassis ear a while back before all this mess and the Transfer case wasn’t loud but you could definitely hear the chain with that I interpreted as a bit of slack. Changed the ATF out of it and it was nearly black.

Took it to a trans shop and shelled out some $$$ for them to tell me the transmission has no issues.

The only thing I can think of is the carrier had a slightly loose fit (I dimpled it with a punch to press on) and maybe spinning under the higher rotational force under the bearing mounting surface? I have no idea. This thing has to make a 3600 mile drive in a few short weeks and I need to know it’s not going to lock up again.

Ideas???
 

Big Bart

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By chance do you have a carrier bearing on the drive shaft?

Could it be tire noise? Perhaps rotate the tires.

Guessing you pulled the axles a couple times. Perhaps you have a axle bearing now going bad?

Can you have someone else drive while you move around and listen in the back of the van? Might help you figure out where the noise is originating from.

Loose chain might be it, usually they grumble, drag, or skip with a clunk.
 

BigVan

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No carrier bearing just the shaft from transfer case to differential.

I doubt it’s tire noise because the noise doesn’t change with road surface but stranger things have happened so I’ll rotate the tires this weekend to see if it makes a difference.

I’m actually gonna just buy a chassis ear at this point and see if I can nail down exactly where it’s coming from.

I would never say that it couldn’t be a wheel bearing but it’s unlikely because I changed out those on the full float as the last step when putting it all back together.

I’m up an hour before work this morning to pull the cover and let it drain out. Hopefully this afternoon or tomorrow I can run another round of gear marking compound and see if I can discover anything.

Good to know on the transfer case. It does sometimes make a low grumble but when I put my hand firm on the transfer cases shifter it quiets down a bit.
 

franklin2

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If the noise started after you did all the rearend work, then it's going to be the rearend. I would take the cover off and get some grease and check your tooth contact patterns, and also check for any metal in the oil and the bottom of the case. Check the backlash again and see if it has increased.
 

BigVan

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I got up at 430 this morning to pull the cover before work. Propped it open with a screwdriver and letting it drain all day. Hopefully this afternoon I’ll have enough daylight to get a dial indicator back on it and check the pattern again. Lucky me, I keep a pretty big tube of GM marking compound around for an old Toyota that I have. Diffs on those things are MUCH easier to set up. Also when it goes back together it’s getting valvoline synthetic.
 

Black dawg

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Were you able to get much preload on the carrier bearings?

Was the housing worn on the left side where the carrier bearing race goes?
 

BigVan

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I would say the carrier bearings have enough preload. They were shimmed until I couldn’t get the carrier in without a deadblow and taking it out took some effort with a pry bar and screwdriver. After that everything was tightened to spec and my measurements in my original post were taken.

No scoring on any of the components or their mounting surfaces. The carrier itself has chew marks from the previous pinion catastrophe but nothing sharp or deep or enough to cause concern.

I was going to get back into it today to recheck pinion preload, backlash and pattern but we just got hit with a massive dust storm so for the sake of my bearings, eyes, lungs and teeth it will have to wait till tomorrow.

Been reading a lot about older vehicles and how even .005 of depth makes a difference with some sets. It patterned good but I may pull it all and move the pinion out about .010 to see if it makes a difference.
 

Black dawg

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If the carrier bearings fit to where they might spin, but arent sloppy, clean them up and use green loc tite on them. I have used it on loose pinion bearing races in the housing, and it always works.

As far as the carrier bearing preload, sounds like you were able to get enough. For long term, it should be very difficult getting them in and out......without a spreader.


I have never been able to get a noisy gear set to be quiet...regardless of settings. Somehow missed the part about the pinion coming off.....probably time to start over.
 

BigVan

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Black dawg, thanks for the tip on the green loctite. That didn’t cross my mind. I’ll pick some up today and hopefully the wind will die down by the time i’m off work.

To clarify, the pinion incident happened about a year ago. Since then its gotten all new components minus spiders and carrier. The carrier has some scars but nothing in any critical areas.
 
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