Diff Pinion Damper- Essential for manual NA6?

adidistyle · Postby **adidistyle** » Fri Dec 20, 2013 12:52 am

I have seen brief comments on MX5Cartalk and elsewhere, but no definitive/qualified answer. My books and manuals don't mention it.

The story so far...
The time has come to replace my NA6 diff. I am looking at all my options, and one is a complete rear end from an auto NA8. Notably, it does not have the Rubber Pinion Damper that I understand is standard on the manual, but the price is right. I plan to upgrade the internals anyway. My car is pretty much a dedicated competition car dríven to/from events, so some sacrifices to comfort are acceptable, but risks to durability are not (apart from those inflicted by me :twisted:

).

My questions are...
What is the purpose of the damper? NVH or something more crucial to the driveline?
Can I run a damper free diff with a manual transmission?
Can the damper be retrofitted to an auto diff? I have read it is a fairly expensive part at $100 plus.
Does anybody here have any actual experience running 7" diff without the damper? Street or track car?

Attached is a pic borrowed from http://www.miata.net/garage/diffguide/index.html
The arrow points to the damper in question. The diff on the right (sans damper) is from an auto.

Auto vs Manual Diff Pinion Damper.jpg

Thanks in advance for your advice,
Adam

hks_kansei · Postby **hks_kansei** » Fri Dec 20, 2013 8:27 am

I've seen ones without a damper on heaps of manuals.
I think the damper was likely more late NA8 and NB that got it, than auto/manual.

It's probably just there to help avoid weird vibrations, harmonics, hums, etc (sort of like the engine's harmonic balancer)

Should be fine without it, pretty sure my GF's NA6 doesn't have it (has a 1.8 diff) and it's not had any problems with the diff in it's 300,000km life (car has 400k on it, but no idea when the diff was fitted)