One of the rear wheel bearings is going bad, and the differential whines loudly at highway speeds.
I should also mention that I have never replaced the differential fluid.
I’m pretty handy when it comes to automotive maintenance; I’ve rebuilt an engine, replaced manual clutches, head gaskets, valves, carbs, radiators, water pumps, timing belts, exhaust systems, etc. So I am tempted to rebuild the rear-end on my own. But a coworker says not to attempt it. He says replacing and aligning the gears in the differential is not “amateur hour,” and that I should only have a person who has the knowledge, tools, and experience do it.
So is it really that hard of a job to do? Do I need fancy measurement & alignment tools to do it? Or can I just purchase the spider gears (or whatever) and bolt them in there?
Another option is to purchase a new & complete rear-end. But where would I find one? And how much would it cost vs. rebuilding the existing rear-end?
Rebuilding rear ends requires some specialized tools to get the pinion and ring gear shimming correct. I received training on rebuilding rearends at tech school but because I don’t have the tools to do it right, I would not attempt it. Like automatic transmissions, that is something I leave to those that make a living doing that kind of work.
The whine is the crucial factor here. If it’s a gear whine, the ring and pinion will need to be replaced. Typically a gear whine will be present during acceleration/cruise or coast, but not both. If the whine is the same on both acceleration and coast, it may well be a bearing noise.
If it’s a ring and pinion problem, I agree with racer72 and your coworker. Replacing them is a specialty and an art. Even with the right tools and a good manual it’s hard to get it just right. Experience makes a world of difference. I’m a professional auto mechanic (30+ years) and I’ve done a few. But I haven’t done enough to do them efficiently. If I had to deal with one, I’d probably sublet or refer the job to a specialist.
This is not to say that you can’t do it. The only special tools required may be a dial indicator, a press, and some Prussian blue for pattern checking. But understanding the interrelationship of the adjustments is often very tricky, it’s necessary to work very carefully to get everything lined up properly, and unless you’re lucky you may well spend a lot of time on it. It could turn out fine, but it’s not out of the question that something may go awry, leaving you with a gear whine and the possibility of having to get another new ring and pinion to start over.
I would suggest a used rear axle assembly. The great majority of differentials last a very long time, and good used ones are usually readily available. Unless it’s the removable carrier (“pumpkin”) type, and I’m pretty sure yours isn’t, it will be sold as the entire rear axle housing.
If it’s a bearing problem, it’s much less complicated. A press will likely be needed to remove/install bearings. The pinion preload adjustment needs to be done carefully. But it’s much more within the scope of the capable do-it-yourselfer than a ring and pinion replacement.
The rear passenger-side bearing has been making noises ever since we had the van. (We bought it in 1999.) I always figured it wasn’t a major problem, and have done nothing about it. (I have replaced rear bearings on other vehicles, but have not gotten around to replacing this one.)
The “whine,” on the other hand, is getting to be very annoying, and is progressively getting louder. It only happens during acceleration.
I would rather not install a used rear end, opting instead to have the current one rebuilt w/ new components. I guess I’ll look around to find someone who is experienced at doing this.
BTW: Do you think I created or exacerbated the problem by not changing the differential fluid?
Hard to say. On the one hand, most manufacturers recommend replacing the fluid at some point, usually 30K or 60K miles. It does get contaminated with metal particles, especially during the break-in period, and it’s certainly possible that a fluid change may have forestalled or averted the problem.
On the other hand, lots and lots of rear axles don’t get their fluid changed and still last years and years and hundreds of thousands of miles.
In this case I would suspect that debris from the axle bearing may have contaminated the fluid more than the average. Replacing the bearing and then changing the fluid would have been the best bet.
Wheel bearings will not usually whine, or if they do, they are totally dry, and would make a more course sound. In my experience, ring and pinions whine, not wheel bearings. If you haven’t already done so, check for tire cupping due to improper or no balancing. This can cause quite a loud whine on acceleration, and often time cannot be easily seen unless you jack tires and spin wheels. Cupping on truck tires is a common whine in the rear end. (g)
Also, I have seen GM differentials go hundreds of thousands of miles with no wear, even without gear oil changes. There are also many products on the market which will extend life of ailing rear ends and cut down on friction, which cuts down on whining. I have used a few with great results, so this should not be overlooked if it does turn out to be your ring and pinion, which I doubt unless you were overloading vehicle changing the pinion angle to drive shaft, so check your pinion seal as this is an indicator for overloading if it is leaking.
A local shop did bearings and seals in my 85 E150 year before last for around $500. I’d considered a yard rear, but by the time I play with mounting, the brakes and everything else, his quote was looking real good. The rear had a cruise whine when I bought the truck with 48K miles, and has the same whine at 395K.
