diggyd357

So i changed my manual transmission fluid and differential fluid today using Redline mt90. Only about 1 quart of the darkest, nastiest looking fluid come out of the transmission, but I got 1.5 quarts out of the differential. I put about 1,75 quarts in the transmission, but nothing was trickling out yet... I stopped. I put the other 1.25 quarts i to the differential. Your thiughts ???

Car details :
2004 RX-8
103K on car
3k on this rebuild.
Ive been experiencing an occasional slipping during spirited driving after i e been driving for a while. Itll slip a little bit and then its back in business. So i went with the fluid change first.

CaymanRotary

Fluid change isnt going to help with slipping. Sounds like you need to change your clutch.

diggyd357

Clutch was my first thought too, but I was thinking perhaps a leaky input shaft seal wetting the clutch. With the fluid being so low in the tranny would you think it could be a possibility? That fluid had to go somewhere.... Then when i added the 1.75 quarts the slipping has become considerably worse. So bad that i cant drive the car anymore. After about 5 or 6 minutes of driving , everytime i put it in gear it revs up to around 3500-4000 rpms before it finally gets going good . This is so disheartening..

CaymanRotary

Not really. Any slippage I always attribute to the clutch. It's not a big deal can be done for $1,000 parts and labor. Search Exedy clutch kits.

Edit: either way even if it's what you think it is it still requires removal of the tranny. May as well upgrade even of the old clutch is usable.

TomD_Cincy

iTrader: (2)

Did you put MT90 in both the transmission and the rear end? If so, you probably need to drain the rear end and refill with 75W-90.

diggyd357

Yes I used MT90 in the rear diff... I'll drain and fill with correct fluid.

I'm just trying to figure out where that transmission fluid went ? To be so low, there has to be a leak....since changing the trans oil I have a ton of oil coming from the rear main seal area and the slipping is 10 time worse than before.... The fluid leaking smells like the mt90. FULL DISCLOSURE: I know nothing about transmissions lol. Im just concerned about bringing the car somewhere and they say "Yuh need a new tranny buddy" or i take it and say "Just replace the clutch", but that doesn't solve the problem after its done. I dont know any trustworthy mechanics which is what lead to me teaching myself to fix my own vehicles, but in just not sure id be up to this task even IF i had the tools.... To top things off, my harmonic balancer went out today in my other vehicle. So im about to do my first harmonic balancer in the morning. What a weekend sigh....

Loki

iTrader: (1)

Sounds like the seal at the input shaft is gone and is leaking onto the clutch. That trans needs to come out for the repair.
Since the clutch is contaminated with oil you may want to replace it at the same time, but you can check that when you have the thing apart.

Just to be clear, when you say 'rear main seal' area, you mean between engine and trans?

diggyd357

Correct.... where the trans meets the engine.

TomD_Cincy

iTrader: (2)

Sounds like transmission input shaft seal to me. Transmission definitely has to come out to replace it. The part itself is less than $20 IIRC. As others have recommended, you might as well replace the clutch while the transmission is out..

if you weren’t getting any weird noises out of the transmission, It’s possible the low fluid level hasn’t resulted in much damage. Though my guess is you’ll need it rebuilt/replaced sooner rather than later.

i wouldn’t drive it until you get this fixed.

Steve Dallas

Yep. Sounds like the input shaft seal on the trans. That is not a difficult repair, but it is time consuming, since the trans has to come out. You'll have to do the clutch too, and while you are in there, the pilot bearing and rear crank seal should be replaced.

diggyd357

So other than a transmission jack, is there any other special tool or tools i would need ? Im actually considering doing this myslef as it would be after first of the year before id be able to put another $1,000 into the car. Its about to be Christmas season and I have 4 kids so this time of year is the worst for having extra money.

Loki

iTrader: (1)

Consult the shop manual: M A Z D A

It's a little outdated, but most of important info is there.
The tricky-ish part is aligning the PPF when reinstalling everything. If you're on a lift and have trans jacks, it's not difficult, but if you're down on the garage floor, it suuuuucks.

If you remove the flywheel (which isn't a bad idea, to at least clean off any oil and replace the rear main seal while you're in there), you'll need a giant 36mm socket (I think?) and a torque wrench that can do north of 300lbft.

Be careful not to pinch the O2 sensor wiring when reinstalling.

Steve Dallas

I have done a few RX-8 and several Miata and MX-5 clutches, and can do one in about 4 hours. A first timer should expect to spend twice that amount of time over 2 days. Most of the shop cost for this job is labor. You can do it all for around $400 yourself, if you have the right tools.

Mazda transmissions are tall, which means you need TALL jack stands, and possibly 2x12 lumber to stack underneath. A low profile transmission jack is helpful for reinstalling the transmission, but I usually just bench press it to take if off (~60lbs). You also need at least one extra standard jack stand to hold up the PP frame, while you work (I don't disconnect it from the diff).

As for other tools, you need a good metric tool set, a lot of long extensions, 3/8" and 1/2" drive torque wrenches, a tape measure (for PPF alignment), etc. You also need brake cleaner and a good tacky grease.

I have used the Exedy OE replacement clutch kit in the RX-8s I worked on and the owners had good results.

Do the slave cylinder and all the seals while you have it apart. Use only genuine Mazda seals.