I did not pay attention to which way this part was facing when i tore the car down! It's off a 77, It will go on either way but I want to make sure I get it right. It attatches under and behind the rear diff. Does any body have a name for this part and which way it faces? Thanks in advance.

I can't find anything that looks like that on google images, I looked because I have a '77 and it doesn't look familiar to me.  I haven't taken my differential out though, just replaced the mount.

 

Good luck.

Edited July 31, 20159 yr by siteunseen

Okay, that was driving me nuts.  Mine does have something like that, it's called a "Damper Plate" made of stacked iron.

 

If you click on the picture in the first post you'll see how it goes.  http://www.classiczcars.com/topic/35878-odd-part-near-rear-diff/

Edited July 31, 20159 yr by siteunseen

Thankyou, thankyou. I figured it was a counter weight or something. Back to another full day of z ing. Three of the four brake hoses wouldnt come loose, thats gonna kill my day.

Thankyou, thankyou. I figured it was a counter weight or something. Back to another full day of z ing. Three of the four brake hoses wouldnt come loose, thats gonna kill my day.

I tried the 10mm brake bleeder wrench, rounded the valve off quick too.  You need two pairs of good, clean jaws Vise-Grips.  It's the only way, unfortunately.  

 

Are you putting the stainless hoses on?  I had to use needle nose Vise-Grips to hold the square piece.  Don't know what it's called but they're on all four.

 

Maybe soaking them down with some kind of penetrating spray would help?  I use 50% acetone mixed with 50% automatic transmission fluid in a spray bottle.  It's so much more for a lot cheaper price.

Actually that part attached to the diff. and was Datsun's answer to vibration dampening. My "73 came with a smaller version. FWIW, I took it off, didn't notice it was missing. You don't really need it. At least, I didn't.

 

Cheers, Mike

It bolts on to the cross member that the diff mount is bolted to, but not the diff itself.  My guess would be that it's mass is meant to damp the clunk from the diff when shifting.  Probably makes the cla(u)nk turn in to a thud.  

 

My own theory on the clunk is that it happens when the nose of the diff comes back down on to the cross member after getting lifted during acceleration.  There are videos out there that show it lifting and falling while driving.  If you look closely at the diff mount when it's in place you 'll see that there's only about 1/8 inch of space between the metal plate of the mount and the edge of the cross member.  You can also see that Nissan had a little button of rubber molded in between the two plates to stop them hitting when the plates compress.

 

I have two of those dampers and they make nice anvils, and handleless hammers.  Also convenient for when I had to dress a cutoff disc down to a smaller diameter.

 

Overall, the system is an odd collection of thoughts and fixes.  The RTz mount is much more effective.