I thought this was important enough to start a new thread for the people who intend to change their own manual trans and differential oil and who plan on getting new crush washers instead of reusing the old ones. Apparently, there has been a lot of confusion on the other gear oil threads regarding the part numbers.



In one of the most useful and most cited resources, forum member "jdl" posted pictures of all the parts, torque specs for the four bolts (transmission fill and drain bolts & differential fill and drain bolts), trans & differential oil capacities, and crush washer part numbers. The URL is http://www.5cats.org/rx8/trans_diff_refill/.



"jdl" was correct in stating that the transmission fill and drain washers are identical (they have one part number). However, he listed only one part number for the differential washers, suggesting that the differential fill and drain washers are also identical to each other, which is incorrect. THE DIFFERENTIAL FILL AND DRAIN WASHERS ARE IN FACT DIFFERENT AND HAVE DIFFERENT PART NUMBERS. Even the pictures on jdl's website show clearly that the differential fill washer is COPPER whereas the drain washer is not.



In the "Royal Purple Tranny/Diff Fluid Swap" thread started by forum member "brillo," another forum member, "rev-2-9k," correctly noted that the differential fill and drain washers are different and have different part numbers. However, he listed an incorrect part number (probably an inadvertent mistake).



It seems many forum members have just bought whatever crush washer and reported no leakage and everything fine. But if you wish to stick to the details, here they are:

* manual transmission fill crush washer: Y601-17-361; silver in appearance
* manual transmission drain crush washer: Y601-17-361; silver in appearance

note: the manual trans fill and drain crush washers are one and the same

* differential fill crush washer: 9956-21-800; COPPER in appearance
* differential drain crush washer: 9956-41-800; silver in appearance

note: the copper differential fill crush washer is about 2.5 to 3 times more expensive than the differential drain crush washer.

note: the manual transmission crush washers cost slightly less than the differential drain crush washer.



BTW, you can use the prices on Rosenthal Mazda's website as a rough guide. The URL is http://www.finishlineperformance.com/rx8/rx8_maintenance.html. The couple of local dealerships I called had significantly higher prices than Rosenthal's but I was able to negotiate the prices down a bit by citing Rosenthal's prices. Please note that Rosenthal also fails to differentiate between the differential fill and drain washers, stating only the price for the drain washer at $1.13 each. Their price for the manual transmission fill/drain washer is $0.78 each.



The parts guy at a local dealership was the first person I talked to who knew what is going on with the washers. He also explained to me how the part numbering system works: the middle two-digit number describes the material; the last three-digit number describes the size. So the 17 from the trans washers and the 41 from the differential drain washer indicate they are made of different material even though they are both silver? He wasn't sure.



I hope this helps.

THANKS!

I did my fluid change last month and followed the before-mentioned thread religiously. The copper / aluminum washer thing puzzled me also. Since the copper washer was not in bad shape and is used on the FILL plug I thought the risk of re-using it low. Now I know what to get next time.

Please pardon my ignorance, but do these washers have to be replaced when changing the diff., and Trans., oil? Thanks.

K

that's what they are for. it's not mandatory, but its a good idea to.

I replaced my oils multiple times and reuse them always, never an issue

Six months ago I could only order aluminum. The parts department said copper was "phased out - you don't want them".

Six months ago I could only order aluminum. The parts department said copper was "phased out - you don't want them".

Your parts department is lying to you. Dealers generally don't stock the copper, but they are available for order if you really want them. Also, RX-8s still come from the factory with the copper washer; why would they be "phased out" for changes after the factory fill?

We managed to resurrect a thread from someone who got banned?! Interesting...

Thanks for the bump as this is on my list of things to do soon.

We managed to resurrect a thread from someone who got banned?! Interesting...

Thanks for the bump as this is on my list of things to do soon.

but the question that we are answering is directed to the person that bumped this thread

Just to bump this useful thread.

I called a few SF Bay Area dealers and none of them carried the manual transmission crush washers. Most carried the differential washers. I called Cardinale (Salinas), Oak Tree/Almaden (San Jose), and Menlo (Redwood City).

I ended up buying from Oak Tree in San Jose on Stevens Creek. They were the cheapest. I had to order the two manual transmission washers.

What I paid at Oak Tree:
* manual transmission fill crush washer: Y601-17-361; silver in appearance $2.28
* manual transmission drain crush washer: Y601-17-361; silver in appearance $2.28

* differential fill crush washer: 9956-21-800; COPPER in appearance $6.13 (Ouch!)
* differential drain crush washer: 9956-41-800; silver in appearance $1.52

If you have a copper crush washer and you can't find a local replacement, you can reuse it by annealing it. Heat it until it glows cherry red with a Mapp or propane torch, then quench it in water. It will soften up again and you can reuse it. You can do this a few times before it gets out of shape enough that you should replace it.

Copper gets work-hardened by crushing it, annealing it softens it up again so it makes a new seal.

I'm guessing that the dealers are going to Aluminum because of the high price of copper these days. Aluminum works fine once but you can't reuse it by annealing.

I got the copper crush washer for my last oil change. and that was like couple months ago.

At first I was like *hmm copper wtf?*

but I installed it anyway becuz it fits perfectly.

so the fill and the drain crush washers are the same? (for the M/T)

Just called Tustin Mazda: they're out of stock but I'll be swinging by later on to order them.

Just called Tustin Mazda: they're out of stock but I'll be swinging by later on to order them.
You might want to double check another dealer to see if they have stock and/or lower prices.

Good luck!

The parts manager is a forum vendor here...he usually takes good care of me. :D: Thanks though C&D, thanks for looking out.

The parts manager is a forum vendor here...he usually takes good care of me. :D: Thanks though C&D, thanks for looking out.
De nada. So are you going to do the fluid changes yourself? I don't think I'm up for it. I'll probably have a local mechanic to it for me.

I'm too lazy to change all the fluids. I've actually got a Rotary only shop near me so I'll just go there. (they are the ones who did the tranny fluid swap the first time)
I'll probably have them do oil, tranny, differential, and break fluids all at once

you can reuse those washers more times than most people will ever see in their ownership

you can reuse those washers more times than most people will ever see in their ownership
It's $12-13 bucks to change all four washers and we're already putting in good synthetic--might as well treat our 8 right!