hey guys, i heard threads talking about how changing the tranny oil makes shifting much smoother. So i bought 4 bottles of royal. (dont worry, did my reasearch, pretty sure i got the right type). The thing is i dont kno how to change this oil, yea yea, being a girl sucks. Should any mecahnic know how to do this, at a jiffy lube or something??. If so, how mouch would they charge me, and would they know how to do it correclty. i.e thats its actually a little less than the 4 quarts. thanks

 

Yeah, any mechanic should know how to do it, its pretty simple.

There are 2 big bolts on the transmission 21mm I think, First unbolt the top one, then, unbolt the bottom one and the tranny fluic comes out of the bottom one. Replace bottom bolt, then using a length of hose and funnel or a pump just fill it back up till it begins overflowing out of the top hole.

Differential Fluid is the same.

The bolts on the tranny are on the drivers side of the transmission. The bolts on the Differential are facing the rear of the car if I remember correctly.

If you have the right tools you could do it in your garage in about an 45 minutes.

If you take it somewhere its likely to cost you $80-$100. And you will not know if they didn't fill it enough, or filled it too much.

 

the above sounds right

I want to do mine before winter - with the stock oil my first shift of the morning on a cold day was always resulting in a lound crrruuuuuunnnnncccchhh

 

2 bolts:

drain bolt is a 23mm
fill is 24mm
and it holds almost 3 redline bottles of fluid

Just did mine and also do the diff why you are at it
takes 1.4 bottles of redline.


-Ryan

 

This would make a good DIY thread if there isn't already one.

I think I'll be changing trans and diff fluids for my next 'mod' :o

I just can't find a place that sells Royal Purple around here so I might be using Mobil 1

 

There is a DIY already.

Once you can get under your car, it's almost self-explanatory. Drain from the bottom bolt hole, fill from the top till it drips out. You will need plastic tubing and a funnel, or better yet plastic tubing and a little hand pump from Northern Tool or whoever (like $5 or something).

The difference is immediate BTW, you feel it before you even start up your car. It's probably the most cost-effective "mod" you can do, heh. Mazda recommends changing oil after the break-in period, they really should recommend the same for the transmission oil.

 

DIY tranny/diff fluid swap thread:

https://www.rx8club.com/series-i-do-yourself-forum-73/diy-transmission-differential-fluid-replacement-35115/

there's A LOT of neat stuff in the DIY section, use it!! :p

 

There is a great difference to the shifting if you use 2 jugs of Redline 90 weight gear oil, then top it off with Redlines' MTL, which is a lot thinner.

Smoother, less crunchy in the cold, slicker shifts at all times, and silent.

"Hear me now, und believe me later!"
Hans und Franz.

S :D

 

I swapped the diff and tranny oil to redline and there definetely is a much smoother feel to my gearbox . :D

B...free
michael

 

Ill be doing the switch to syn in the next few weeks (8k miles) in the miata it made a noticable differnce, esp in the diff, the LSD got a lot better engagement

 

I read through the DIY thread but I'm a little confused.

Can someone confirm that the following is correct?

1. 3 Qts of Redline 75w/90 fluid
2. change both tranny and LSD.

THANKS!

 

you need 5 quaRTS TO DO TRANny and diff.

 

Ok, when are the synthetic haters going to chime in because it isn't rotary transmission specific synthetic oil and Mazda didn't say you could?

 

LOL, so true

Redline MTL here, tastes great and is less filling, wouldn't you like to be a Pepper too ...

 

the diff calls for 90W and the tranny calls for 75W90

anyone see a problem just sticking a 75W90 synthetic gear oil in each (i believe the diff does not call for any special additives)?

 

all good advice BUT remember to loosen the TOP bolt 1st. Just in case. I have seen someone remove the bottom bolt 1st and the oil is draining(slow but draining) and then COULDNT get the top bolt off. So they where stuck with a trans with no lube in it! Or diff as the case may be.
olddragger
RG synthetic prowler?lol

 

also note that the trans lube spec is GL-4 and the diff fluid is GL-5 spec, many 75W90 gear lube oils are GL-5 spec and my experience is that the synchros don't work as well with GL-5 oil.

Mazda also released a TSB allowing multi-weight GL-5 oils for the diff

http://www.finishlineperformance.com...4-03-1268a.pdf

the RX-8 LSD is a Torsen, it does not require additives, additives are typically for clutch pack LSD's

 

oops... yea forgot about the Gl-4 vs GL-5 aspect

thanks for sharing your experience

 

2 each is right.

 

Since each of them require less than 2 quarts of oil, but total always more than 3.

You do the math, 2 Each is about right.