Redline Transmission Oil
 

Heres my question: You guys say I need to order 2 quarts of each Redline MT-90 Trans axle Lube and Redline 75W90 Gear Oil. I'm guess this two go into two different spots, correct? You guys have to forgive me for my stupidity, this is my first time trying to change a manual transmission oil.

I would get 3 of each just in case something happens. The 75W90 is for the rear Diff and the MT-90 is for the 6-speed.
http://www.5cats.org/rx8/trans_diff_refill/
$ https://www.rx8club.com/series-i-tech-garage-22/clarification-manual-trans-differential-crush-washers-part-numbers-44584/ sould also be of help.

MT-90 in the transmission and 75W90 goes in the rear differential. I just recently got them done and the tranny feels wonderful. I can't believe how smooth it is. It was already fantastic, now it's like butter.

Don't take this personally, as almost everyone else on this forum seem to do it (including Rosenthal Mazda's web site), but it's Red Line (two words) as in http://www.redlineoil.com ;) .

Yep, the MT-90 is for the manual transmission and the
75W90 is for the rear differential .......... if you have not already search for the DIY on this subject, I'd recommend doing so as it contains a ton of helpful info. Don't forget to buy the four fill and drain washers.

Make sure you DO NOT get the 75w90ns Gear Oil. The 'ns' is for non-slip differentials. Most stores stock both next to each other so it's easy to grab the wrong bottle ;)

When I changed mine out, there weren't any fill washers.. only drain washers.. heh..

I must admit, I can't remember how many washers there were....I just remember not bothering to replace them. They are 100% fine for re-use. Save yourself a trip to the dealers.....

How many times would you reuse them? Do you reuse you motor oil drain plug washer? If so, how many times?

Personally, I'd rather not reuse mine ........ WTF was Mazda thinking when they wrote in the Factory Service Manual to replace these compression washers :) ?

Well, my V8 Ford has never had it's sump washer replaced....I've personally changed the oil on it thirteen times, and it doesn't leak a drop. The 8's tranny and diff washers will last the life of the car.......

Yeah, as long as you don't over tighten and crush the washer it should be fine. Granted, they are technically "crush washers" :p

I suppose when they design these things, the engineers do have to make allowances for the below average, ham-fisted, meathead, knuckledragging, backyard mechanic :)

........like me :D .

I just changed mine 2 weeks ago, immediate difference in shifting, niceeeeee and smooooth!

Lucky bastard. I put MT 90 in a while back and it made no difference to the notchy 1-2 shift at all....

Thanks guys, I appreciate all the help. I will hopefully be successful next week when I change the oils.

where in MD are you located? I have some of the tools / aids I used. You'll need a 23mm and a 24mm socket and a torque wrench is recommended. Take your time. Read the threads previously posted - printing and reading over a few times is best.

Do you believe in using a torque wrench when doing work on your car :) ?

Well, some people don't use a torque wrench to tighten things... they just keep tightening until they can't turn it anymore.. that's what most people do when they destroy these washers.

Good point and yet another reason why it seems foolish to me to try and save a few bucks by not replacing the crush washers considering it cost ~$40 for the fluids + our time/labor.

My dealer has these washers listed at a price of $2.10 each. Kind of pricey, but is it worth the security?

These washers are soft aluminum so they can be "molded" or "crushed" when you tighten the drain bolts to provide a proper seal between the bolt and the hole. The washers for the tranny and differential are the same size. I haven't looked into it, but you may be able to get aluminum crush washers at someplace like Home Depot for a lot cheaper than your dealer sells them for.

I'd say, IMHO of course, it's worth it. They are a specific composition, outer diameter, inner diameter and thickness, all for various reasons. If you want to skimp, you could probably get by with reusing the 'best' of the fill / drain plug washers when you put the fill plug back on. But if you want to use new for both fill and drain plugs, make sure to get two of them for the tranny and two of the for the diff. They are different. IIRC the rear diff is the same as those used on the Miata oil drain and maybe it's tranny and diff as well.

I'm near College Park, Maryland

Hmm.. my dealer lied to me then. they told me all the washers were the same ;) hehe

Check these fluid/washer prices out - much better:
http://www.finishlineperformance.com...intenance.html

Seems like the place to get the fluid and washers. I'm not sure why they don't list the fill washers, though?

There aren't any fill washers, just drain washers...! I could swear I mentioned that earlier.. i must be losing it....