Diff Noise

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I'm about to do my axel service and bearings. My question is I think the pinion bearing might be bad as well. I have a noticible whine that seems to go away when I let off the gas. Question is can I just live with the wine if I do the axel service and it doesn't go away. The axel ran pretty low on fluid but not bone dry...some still came out when I pulled the drain. There was some metal on the plug, but not a crazy amount. The truck has a lot of miles...240k so I don't want to get crazy with it and have no problem living with the noise.
 
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Also, If I just get an assembled third member is it a bolt in affair? Seems like if I'm gonna do it it might be the way to go. Just do it all while it's pulled apart.
 

Cruiserdrew

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Also, If I just get an assembled third member is it a bolt in affair? Seems like if I'm gonna do it it might be the way to go. Just do it all while it's pulled apart.


No reason to do this. If you take it all apart, just take the differential to a differential shop and have them put new bearings in it. With you doing all the grunt work, it should not be to expensive-likely $100 for the bearings and $150 to set it up.
 
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Awesome...Thanks

It is most definitely not the wheel bearings and given how low the fluid got I am strongly leaning towards the bearings. From what I have read given that it is on acceleration/under load and quiet on decel it would seem to be the carrier bearings. At about 50 with my foot on the gas it is most pronounced. let off the gas...noise much quieter. Trans or t case in neutral...no noise. Does that sound right?

If I can get it done for what cruiserdrew states it is a no brainer while I have the axels apart. I have clicking on turns too. I need to go ahead and disasemble it and make sure the birfs are o.k.

I'm not discouraged though yet. It has some miles on it. Part of me wants to go ahead and pull the motor and rebuild it and do all the seals and stuff. I'd have a like new truck at the end of all this ready for another quarter million miles. The truck seems solid...just old.
 
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I had similar symptoms as far as noise level, and it turned out to be a worn drive flange. They can make a howling sound upon acceleration, and mine was the worst at around 50 mph. It was hard to diagnose the sound when driving, It sounded like the front diff for sure, but was the drive flange with 250 k on it
 
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And would the copious amount of up/down play in the front wheel point to this. It feels like really really bad bearings. I know they are shot and could them being really shot effect the drive flange.
 
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What do you mean by up and down play?
If you have true up and down play, like if you jacked up the front and put a long steel bar under the tire and lifted up and had play that would be bad trunion bearings
If you grab the wheel at 12 and 6 and wiggle the wheel hard and have play that would mean your wheel bearings are loose or bad
There something in the FAQ about evaluating your front end if I recall.
 
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play

It's the wheel bearing type play (12-6). But when I pulled it off it appears that the flange and outer bolt are ground up a bit on the D/S. Is this similar to the issue causing the above posters 50 mph howl?
 
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The drive flange is the outermost part of your front axle. It has the cap on it and is attached to the rotor with the six cone washers/nuts. The splines in its center wear over 240 k, and it should be replaced every couple hundred thousand miles. A worn drive flange will cause a howling, but not the type of play your talking about.

I would stick with your plan of a front end rebuild. It sounds like it hasn't been done in your case and the project is a lot of fun, kinda. The drive flanges are about 40 or 50 from cdan, can't remember for sure, and its good to have an extra one lying around in case you strip one, which will happen on vehicles with your kind of miles on it.
Front Axle Rebuild 004.jpg
 
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I'm about to do my axel service and bearings. My question is I think the pinion bearing might be bad as well. I have a noticible whine that seems to go away when I let off the gas. Question is can I just live with the wine if I do the axel service and it doesn't go away. The axel ran pretty low on fluid but not bone dry...some still came out when I pulled the drain. There was some metal on the plug, but not a crazy amount. The truck has a lot of miles...240k so I don't want to get crazy with it and have no problem living with the noise.

The front axle is a high pinion, so isn't as tolerant of low lube as a low pinion.

... From what I have read given that it is on acceleration/under load and quiet on decel it would seem to be the carrier bearings. At about 50 with my foot on the gas it is most pronounced. let off the gas...noise much quieter. Trans or t case in neutral...no noise. Does that sound right? ...

A whine that is affected by load/coast/compression brake is most often gear box, transfer, diff, etc. Hub noises are almost always constant, regardless of throttle, and lower pitch, more of a grumble. The noise difference is from speed, the hubs, carrier, etc turn at wheel speed (slow), the pinion and transfer turn 4X faster.

What you are explaining sounds like pinion, could be bearings or possibly gears. If you are planning to have the axles out, I would also pull the diff and inspect, you are most of the way there and if it needs to come out later, is a big job to repeat.

If it is diff bearings, they are pretty easy to change, some tooling is needed, torque wrench, dial gauge, press, etc. To simply change bearings, no gear setup is needed, just check gear backlash and put it back the same.
 
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Ah, OK.....It is the cap that is chewed up on mine. I will get deeper into it tommorow. If I could have a shop change the bearings in the third member for a couple hundred I'd be willing to pull it and cart it over to them. Looks like a simple matter after the shafts are out anyway. I figure at this point I'll need a new flange cap and the 2 54mm bolts on the ds at a minimum in addition to all the normal service components.

So what would cause the bolt to eat into the flange cap like that. Can bearings be that bad or would it take something more like the drive flanges themselves or something else.

On a side note, This is the first vehicle I have enjoyed working on in some time. Stuff is made to be serviced on it unlike the throw away vehicles I have had prior. After this I should jest have a bunch of oil leaks which won't get fixed until it dies! Rear diff looks good as do the trans and tcase. Brakes good now after 2 weeks of work.
 
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Some pix would help? It sounds like the 54mm adjuster nuts backed out enough that they contacted the drive plate? If so that is way loose, like ready to fall off loose! If it has been run that loose, check the spindle, birf stub, etc, for damage.
 
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I had the same thing you described.My fluid got a little low also.It was the pinion bearings.It was a go excuse for me to switch to 4.88's.At least thats what I told the :princess:!!It was amazing how quiet it was with new gears and bearing.I can't believe I put up with it that long.
 
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Yeah, I'm gonna go ahead and drop the third member and have a shop do the bearings. Hopefully the gears are OK. As to the axel nuts I concur with the looseness. The Passenger side had none of these issues BUT the nuts were finger tight and the lock ring fell off when I tok of the outer grease cap...It wasn't on the shaft. Also the spindle bushing just came right off which seems to contradict what I have seen on here. I'll get some pictures when I get the 54mm socket today and can get the rest of the way in. I only got the p/s tore down as far as I did due to the aforementioned finger tight axel nuts.

I was thinking I may need a d/s spindle possibly. What am I looking for to determine if they are worn. Just groves and gouges. THe bushing on the PS looked good other than the fact it fell right off.
 
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I have EXACTLY the same noise at EXACTLY this same speed so I am subscribing to the thread.

I bought the 80 two weeks ago and change the diff fluid. I had someone do it which was dumb because I am sure I would have noticed that the rear was low if I had of done it myself. Well, the rear pinion seal is puking out grease so I am going to go ahead and replace the bearing along with the seal. At least I will know it has been done and maybe I will get lucky with the noise.

I ruled out u-joints.

Please keep us updated on your solution.
 
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plan of action

Well the plan is all the standard axel service stuff, plus new flange cap and bolts, possibly new drive flanges and bearings on the third member so long as the gears look ok.

My drive flanges look different than the picture. I'll post what I have. Is that the full floater axel in the pic?

So I don't know how much I can narrow down your noise as I am replacing most of the axel guts it would seem.
 
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Ok...I see now the "cap" I am looking at is the drive flange....yeah, the DS will need replaced as probably will the spindle. The threads are jacked on the end of it. Gonna pick up my drifts and a parts washer today and keep digging in.
 
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Update

Just to update the project, I have the third member at the shop getting looked over and should know Monday if I need gears in addition to the bearings. I am sourcing some good used spindles. The D/S threads were damaged enough to warrant replacement I think. The P/S at least needs a bushing but I plan on replacing it too. The D/S drive flange is scuffed up on the inside but the part that rides on the axel seems fine so I plan to reuse it. While the truck was down I replaced the stereo with a Pioneer GPS unit I had in my old Miata and fixed the Drive Light while I was in there in addition to putting the correct grill on and fixing some interior odds and ends.

I/m going to pull everything out of the parts washer probably today and start reassembly as far as I can go without the centersection in.
 

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