Bent pinion flange R-180

[johnbell47]

I need to buy a pinion flange for a R-180. '74 260 Z. Mine is somehow bent which causes a heck of a shake in the driveline. Good used would be great! Thanks!

[EuroDat]

Do you have any experience working on diffs. Changing a pinion flange seems easy, but getting bearing pre-load right is not as easy as poeple think on used bearings.

You could be fixing a vibration and getting a whining diff in return.

It might be easier getting a complete diff.

FWIW

Chas

[johnbell47]

you are of course correct. But what is to say that the complete diff won't also whine? The bearing preload procedure is in the FSM, which I have and have read, Doesn't seem too complicated to me. Or is it

?

[LeonV]

I'm selling a complete early 240Z R180 diff for $50, FWIW...

[Hardway]

Here is a R180 in League City near Houston. Would be a drive to get it but would probably be cheaper than having it shipped. Plus you would get to inspect it in person as it does look pretty dirty in the picture.

Datsun 240z r180 rear end

[johnbell47]

your location in reguard to N.E. Texas etc. oops! see that you are in the bay area. how much for just the flange and to ship.??

Edited June 21, 2013 by johnbell47
error

[LeonV]

your location in reguard to N.E. Texas etc. oops! see that you are in the bay area. how much for just the flange and to ship.??

I assume this is in response to my post? I don't know if I want to remove the flange because without it the diff is probably totally worthless. I don't know if I could give it away. I'll think about it...

[olzed]

Depends how much it is bent, but why don't you remove the flange and have someone with a lathe take a skim off the face. A very simple operation, and i doubt that it would weaken it. No need to take the diff out of the car.

I would machine up a tight fitting mandrel in the lathe,to spin the pinion on. You will see at a glance how much it is bent, and if the mandrel is a good tight fit in the flange, a series of light cuts can be performed on the flange. If you really want to get fancy you can thread the end of the mandrel, and put on a nut to hold the flange.

[EuroDat]

you are of course correct. But what is to say that the complete diff won't also whine? The bearing preload procedure is in the FSM, which I have and have read, Doesn't seem too complicated to me. Or is it

?

FWIW I have changed pinion oil seals on diffs and had mixed results. Whining is a problem and often happens after the pinion re-aligns with the crown wheel. I only had sucess when I did NOT set the pre-load to factory spec. The old bearings are worn and the pinion/crown position is worn to suite. Pre-loading the used pinion bearings will shift the alignment and can cause it to whine.

My advice: Note the position of the pinion nut and then remove it. Check that the pinion flange freely moves up & down on the splines. Remove any lock tab burrs on the nut so it will turn freely. Tighten it the original position and check the tension with a tension wrench. It will be a lot less than factory spec.

Fit the new flange and pinion seal and use this tension to pre-load the new flange.

Its not perfect, but it worked better than factory spec.

Chas

[johnbell47]

I just read a post from jmortensen, that these differentials did not have crush sleeves for pinion preload, he was saying that he just set his 1/2 impact gun to the middle setting and hammered it on.

[beermanpete]

The factory service manual corroborates jmortensen's statement. The bearing preload is adjusted by selecting spacers and shims, not by crushing a corrugated spacer. Reomving and replacing the companion flange should not change the pinion bearing preload or the pinion height.

We changed the companion flange on the STi LSD we have in our Z and there is no apparent gear whine.

[Zed Head]

I think that Eurodat was just pointing out the possibility of a whine. No guarantees that a simple flange swap will be easy and fix the problem without creating a new one. It seems to be that some people work on their diffs and end up with a whiner and others don't. But no guaranteed way to fix the whine if you get it.

Nobody has asked how the flange could possibly get bent? It's pretty stout and would be surprising to have enough force to bend it without damaging something else. Are you sure it's bent, or could you just have internal damage or a bad bearing causing a pinion shaft wobble? You might be just wasting time with a flange swap.