grinn253

edit: here you go: https://www.rx8club.com/series-i-do-yourself-forum-73/diy-transmission-differential-fluid-replacement-35115/
oh yeah, I heard that even Mugatu's dog searches?
Laters!
Edgardo

mysql101

just under 4. I think it's 1.8 and 1.6

map

I paid $10 per quart at the local Pep-Boys. No shipping that way either.

ninjarama

Yep, same here Royal Purple Maxgear for $9.99 at Pep Boys + tax.

Here's my total cost for doing the change including the tools (and thanks to all for DIY infos!):

RP fluids: 4 x $9.99 = $40
Crush washers (from dealership): 4 x $1.20 = $2.40
23mm socket: $4
15/16 socket: $4
socket wrench: $5
Flotool Tubing (to fill diff. fluid): $3
Vinyl Tubing 6ft. (to fill trans. fluid fed thru engine compartment): $4
Torque Wrench (big long clicker type... the rear diff. drain plug was seized and a PITA with a typical socket wrench... I needed more leverage!): $18
Jack-stands: 4 x $7.50 = $30
Stock car jack: Comes with your car!
Oil Pan: $3
Shop paper towels: $2
DIY Labor: 1-2 hours @ $0.00

Total DIY cost: approx $115.00 or approx $50 if you already have some tools.

I didn't have very many tools for this specific job so I went out and bought most of them. The most difficult part of this job was actually re-filling the trans. fluid! It's kinda tricky so you must improvise. I feel really good knowing that I probably saved a bundle doing this myself vs. going to the dealership.

I don't work on cars much at all, but was able to do this myself (with the help of info. found here). You guys are awesome! Many thanks for sharing your knowledge. I'm so happy with the results and my 8 now runs like new @ exactly 45K miles! (I also changed my oil while the car was up on 4 jack-stands)... even dropped in a Green Air Filter while I was at it.

addendum: Oh yeah, and no stinky smell in the cockpit... yet!

swoope

iTrader: (5)

nice job.. good on you.

beers

SiLVeRE8

iTrader: (8)

thanks! cant wait till i get my tranny and differential fluid changed this sunday and hopefully ill feel a difference... ill let you guys know

rotalution

you are not alone, the first service i did i replaced with RP for the transmission and diff. the smell was quite noticable in the car for 2 months.. even after that.. still some faint smell.. and i discovered there was a hole in the first rubber boot cover after the leather cover.... suspecting mechanic poked a farking hole when they put the tranns back up and the gear stick poked it.. when they change the rear diff bcoz of some noise... and this was done at mazda

HOWEVER i dont think is just bcoz the hole that is causing the smell to come in, from another thread of changing short shift kit some part of the shifter actually touches the trans oil too, so i am suspecting over filling would cause the oil to spill out a bit in to the area underneath the first rubber boot, because i discovered little bit of trans oil in the first rubber boot..

ninjarama

thanks swoope!

Okay, 130 miles since the tranny fluid change... happy to report that there's no "smell" yet. Perhaps it's being overpowered by the pina-colada car scent i have in my AC vents? Anyhow, I don't notice it so it's all good.

However, something I have noticed is that going into 5th gear @ 4000 rpm or higher seems to be a little notchy, and sometimes a slight griding sound occurs. That's never happened before, but it seems consistent now and I have to shift really slowly when going to 5th. At lower rpms it shifts very smoothly.. and when car is in idle, shifting is very smooth. Anyone have ideas or know why this might be happening?

SiLVeRE8

iTrader: (8)

changed the tranny and differential fluid to royal purple for about a week now and the shifting seems a little notchier than before and dont really understand why... any idea from anyone?

nycgps

iTrader: (1)

Just make sure you didnt overfill.

and your tranny is functional.

RX8PDX

I just changed both my tranny and diff with RP maxgear 75w90 @ 15.5K miles. I love the feel of the shifting now. The tranny plug didnt have much on the magnet, but the diff was caked.

I also bought a case of 5w20, and changed that and put in a Mobil1 oil filter.

No smell.

SiLVeRE8

iTrader: (8)

my tranny was replaced by dealer about 7k miles ago and was quite smooth before i changed out the old fluid. the reason why i changed it out was because i thought it would be better. anyways i thought underfill would cause such problem? so how would you know if it is just right? thanks

devildog1679

One question for all you experts. Is there any danger in overfilling the tranny or diff. I may have overfilled the tranny by .3q, it took about 2.1q. The rear also took about 2q. What would the symptoms of a overfilled tranny and diff be? Are you suppose to wait till the dribbling stops before you plug it? Thanks.

devildog1679

Anyone have an answer?

sosonic

I've had my auto transmission fluid changed and there is no smell.

auzoom

Just wanted to add that I have had RP Max gear in diff and gearbox, then changed to Redline lightweight shockproof.

My RP MaxGear lasted me 4 track sessions and 9 months (I shouldnt have but I did ) before it started to feel yuck. It was filthy when it came out but that was my fault for leaving it to long. Changed to RL a month ago and felt better but 1 month later and 2 track sessions and its horrid again.

I am going back to MaxGear.

As for overfilling, I cant see any damage being done but, i believe there are breater holes in the diff and so possibly overfilling the would caue the smells people are getting.

Icemark

RL lightweight shock proof is really a 70W140 oil and probably not the best choice for a tranny. Better for rear ends. In a tranny you would be better off using Super Lightweight which is a 75W90 GL5 gear oil, but with some trannies it may be too slippery and you may crunch syncros a little.

auzoom

Understood but I wouldnt have thought that would cause it to deteriorate faster?

Icemark

Could be one of two things:

Probably the opposite actually happened. It normally takes about 50- 100 miles for the Redline gear oils to become meshed in with all the gears and force out the old lubes, when that happened you probably didn't have enough friction to keep the syncros from clashing.

Or

The weight when warm was too thick and exceeding 220F, so you were getting break down of the gear oil (almost all GL-5 gear oils start breaking down around that point).

In the old days of brass bushings and syncro gears (like the FC gear boxes), 220F and mobil1 or Valvoline synth gear oil and the lube starts breaking down due to the acid build up.

a test of the gear oil would show which one was the case.

auzoom

BUT!!!!!! why the redline and not the maxgear? Excuse my realy uneducated knowledge here, but in theory as you said the redline is 80W140 and so should have better viscosity at higher temps. I would have thought it was better able to deal with the higher temps than the maxgear. I had never thought of testing the oil afterwards.

I have a friend who is an auto-transmission tech so will ask him if he is able to.

ninjarama

anyone know what the stock Tranny/Rear Diff lubricant is for the rx-8? I put Royal Purple in about 1K miles ago, and so far have experienced grinding downshift to 2nd & 5th gear, and notchy upshift into 5th above 4k rpm. I'm thinking about going back to stock fluids but not sure what Mazda uses.

LionZoo

The stock factory transmission oil is a straight 90 weight.

ninjarama

thanks LionZoo... is there a particular brand they use?

LionZoo

No idea. As it is, it's difficult to find a straight 90 regardless of brand.

Icemark

There are quite a few Redline gear oils. The one he brought and was using was in the Shockproof line.

Shockproof oils have different flow and shear characteristics than even conventional Redline gear oils.

And from red line on the oil he was using (light weight shock proof):
He should have used Heavy Duty Shock proof, if he felt the need for shock proof:
I actually normally use Redline MT-90 for most manual tranny applications requiring a 90W: