Rear diff mounting orientation

[Fairlineguy]

I have just removed my 4speed diff to replace it with a 5 speed diff And noticed that the mounting on the 5 speed diff is on the other way round.
The 4speed mounting has a F and an arrow so assume that one is correct
Has the 5speed been put on the wrong way or are they that way to move the diff back?

 

[jonbills]

I may be wrong, but I think they're different diffs - R180 and R200, and they have different mounts.
I think you need some other parts to go with it to replace an R180 with R200.

some info here: http://www.zhome.com/ZCMnL/tech/R200.htm

 

[johnymd]

Does the new diff look bigger?

 

[Rob Gaskin]

This is quite a good reference picture showing the two diffs.

Note the front mounting and also the rear moustache bar orientation.

 

[richiep]

Remember the diff was moved back 35mm during the 240Z's run when the switch was made to the one piece prop and the curved rear transverse link (as opposed to the earlier straight one). I think this was to correct the half shaft angles?

If the new diff is an R180 too, it will just be a case of using the original diff mount insulator to position it correctly (or turning the insulator around maybe?).

 

[Fairlineguy]

Yep . Seems that Datsun moved the diff back 35mm in order to make the drive shafts run at 90deg to the proshaft to reduce wear and noise .(found a ref in the z car story book)
Obviously archived by flipping the diff mounting around. Now the question is do I move the diff back on my series 1 car or leave as original?
Any one had any experience as to if the early set up is noisy?

 

[richiep]

To move it back you will need the later curved transverse link for the suspension (lower bar behind the diff). And move the diff strap back.

Leave it original IMO unless you are making room for an R200. My car is an early 71 and has that setup. All cars up to about mid-72 have that setup. It's not something I've ever heard people noting as an issue.

 

[Fairlineguy]

Cool if it's not an issue having the early set up sounds best to leave as is.
However my car doesn't have the rear anti roll bar ..Did they start fitting them at the same time?
Thinking this would be worth fitting

 

[richiep]

I'm guessing yours is a U.S. import - in which case the 240Zs never had a rear anti roll bar fitted, and lack the brackets, unlike the home or other export markets (who needs handling when driving in straight lines between stop lights, etc.!!). To fit a rear bar will require one of the aftermarket solutions that attach to the rear via the drop links behind the diff. Like this:

http://www.whiteheadperformance.com/products/suspension-techniques-rear-sway-bar-51075-datsun-240z/