Is it worth replacing the bearings on an R180?

[djwarner]

I'm on a one year sojourn making my Series I S30 with 179K miles one of the best driving ones around. Started with new struts all around, next came differential mounts fore and aft, flushing and cleaning the A/T, then new wheel bearing in the rear, and new bearings in the front.

 

Among other things I've noted is a whine between 45 and 55 that changes pitch between driving and coasting. I suspect the diff had been run with little or no gear oil for some time as both axle seals had to be replaced and the fill port was frozen shut. Replaced the diff oil with 145/80. Now it doesn't sing until its been driven 30 minutes or so.

 

Evaluating the removed bearings, I've found radial and axial excessive play in the rear bearings and a very lumpy front bearings. After each change, I have been surprised at how much of the noise I thought was coming from the diff was actually caused by the bearings.

 

This brings me to my question. The old Datsun expert said nobody ever serviced a differentials because no one had the proper tools. They were simply replaced. I also realized that even the diff on my 350Z has some detectable noise at 18K miles.

 

The questions are: Would it be a reasonable job to pull the old bearings in the diff without attempting a full realignment? Any special tools/skills required? And would the bearings only  replacement yield a significant improvement?   

[johnc]

Your old Datsun expert is mistaken.  Lots of R180s get serviced with new bearings.  Your noise issue is more likely with the ring and pinion then the bearings.  It would be a good idea to completely service the diff including preload, engagement, and backlash adjustment.  You should also check your diff mounts.

[JMortensen]

I wouldn't put bearings in an R180 unless it was a rare gear ratio or something like that. If not, just go buy a used one. R180s are a dime a dozen and putting all the money and effort into replacing bearings in a diff that was run low on oil and might have R&P damange doesn't make a lot of sense to me. I would save the money for something that will actually provide a benefit.

[BluDestiny]

You can totally service these diffs, but in your case it may be easier to just find a 4.11 ratio diff out of a 720 4x4. That's what I did. 

[RebekahsZ]

Lots of different views-here's one more. Price the parts, put a value on your labor (or someone else's labor), then price a used ancient R180 Z-car replacement diff. Then price a Subaru R180 LSD and a set of johnc's axle adapter flanges (I think being sold by someone else now). You will LOVE that diff. Plus you can get one that is low miles and clean in and out. Finally-don't over analyse a noisy R180. I've had a bunch of them and they were all noisy,yet I've never had one fail. Consider a thicker carpet pad or turn up the radio and drive it till it fails.