Pain in the Rear(end)

[Exdamyankee]

Well, my stepson walked in this evening after being out with the Z all day and announced that he thinks "there's a problem with the car." Well, to make a short story shorter, it seems as if the bolts holding the cover on the diff had loosened and he lost a mess of gear oil. The ring and pinion are now howling on acceleration & deceleration.

Crap...

I went underneath, re-torqued the cover bolts and was going to add some gear oil to the diff when I dicovered that the fill plug is fairly well seized and the DPO had done a fair job rounding it off at some point in time.

More Crap...

I'm thinking this R180 now needs a rebuild, based on the whine. Am I being paranoid, or do you think it will quiet down again once re-filled with oil?

Fred

Tampa, FL

1974 260Z 2+2 Auto, SUs 80K

[Nissanman]

May as well remove the cover and get those fill and drain plugs fixed.

Then refit the cover and re-fill with diff oil.

As we say in Oz, suck it and see, the diff may be OK:ermm: .

[DatsunZsRule]

That sure sucks. Sorry to hear that.

The answer to whether or not it should be rebuilt is to remove the cover and inspect it internally. If everything checks out good, then reinstall the cover with obviously a new gasket and fill it to the proper level and see what happens.

You could just try refilling it without inspecting it and see if the noise goes away, but I would check it out for piece of mind.

Good luck with it and let us know how everything turns out.

[Ed]

I had a similar situation. Diff ran dry and started to howl. Filled it back up and it still howled. Had to replace the diff. Cheaper than having it rebuilt.

[beandip]

I agree with Ed . Just replace it. From the factory these cars were equipped with gearing that was rather high. You might think of going to a lower gear and improving performance. Although having a young son that drives the Z this may not be a good idea after all. Gary:stupid:

[red_dog007]

If you do replace it, should look at the cost/benefit ratio between that and getting a R200 swap.

[Carl Beck]

It of course depends on how far it was driven with low to no gear lub - and/or how hot it got. But with only 80K miles on the car - it should be fine if you refill it.

Take the back cover off - so you can put it in a vise. Take a butane torch and heat the area round the fill and drain plugs - both inside and outside surfaces - then put a "Pipe" or "Monkey" wrench on the external plug (can't recall if the fill plug or drain plug sticks out).... It's a standard Pipe fitting and a pipe wrench will grip it firmer as you apply torque.

Put a light coating of anti-seize on the threads before you reinstall the plugs...

FWIW,

Carl B.

[Arne]

This brings up a point that I once learned the hard way.

Never drain a transmission or differential until you have verified that you can get the fill plug out.

:stupid: :tapemouth

[DatsunZsRule]

Carl is right on about using a butane torch to heat the area around the fill plug/drain plug as the best way to break 'em loose. I had to do this on my transmission when I serviced it.

Thanks to bone head for rounding off the head of the fill plug for you, hope your still able to get a decent grip on it with a wrench

[DeesZ]

The heat treatment usually works very well, I agree. I've also been known to get it hot around the case and then apply an ice cube to the plug itself.... If I recall from physics class that compounds the dynamic of altering the change in metal sizes and helps free up the plug. It's worked well for me more than once with stubborn drain/filler plugs. On the other hand, I haven't looked at a physics book for 40+ years, so maybe I'm the one who needs advice.

[Exdamyankee]

Well, I managed to drain, reseal and refill the diff with $24 worth of Mobil 1 Synthetic.

Let her down, started her up and took off down the road.

With the crud out she's louder than ever. The diff is toast.

Did I say "CRAP?"

Anybody got a decent R180 3.54 bolt up for cheapsies?

[DatsunZsRule]

Crap is right. Sorry to hear that.

Your son must have drove it too far after the problem happened and over heated it. Sorry to hear that man.