StewC625

Hi guys:

First of all, I did do a SEARCH on this - there are tons of threads, and I was having trouble sorting through them for useful info for me, so thought I'd post up here.

In the owner's manual at the 2-year mark for scheduled maintenance, you're supposed to change the transmission and rear-end oil. I have seen over and over here of people going to either Red Line or Royal Purple synthetic oil.

I take my car to a private shop for its scheduled maintenance and only to the dealership when it needs warranty work (I hate my dealership - Autobarn, Evanston, IL). Questions:

1) Of the two, Red Line and Royal Purple, which do you have or recommend and why? Is there a third brand to consider? Is there a specific grade or product name from these brands to tell my guys to get?

2) One thing I did notice is that folks who have done this report better shifting and less noise - so I presume I will experience that as well.

Is there ANY downside to doing this whatsoever?

My car is an 04 with a September 03 build date, July 04 delivery date - so it's definitely time to do it. I haven't had any diff or trans problems to date - my gearbox shifts smoothly, although there's plenty of mechanical symphony coming from the entire driveline. I presume the better oil will quiet this a bit. Hopefully not too much though!

Thanks in advance,

Stew

DOMINION

I'm sticking with OG Oil as far as the Engine but I might change the rearend with something

swoope

iTrader: (5)

stewy,

i am using rp and am very happy with it... i doubt anyone could tell the diff between it and redline...

the answer is in you owners manual match the wt and gl rating with whatever brand you want. that is it.

from memory i think gl4 works in both tranny and rear end...

do a search for swoope and fluids. you will have to back away... brillo gave me the exact answer you are asking...

btw, if you need a link for rp pm me...

from a rude elder.

beers

daisuke

there's no downside to doing it, I've heard very good things about redline, but I haven't heard much about RP so I can't say on that.

Ike

I don't like synthetics for any manual tranny, it's almost too slick and often will feel very good (shifts easier) at first only to cause problems down the road. The synchros should have a little more friction IMO. The Pennzoil Synchromesh/BG synchroshift has worked really well and I'd recommend it to anyone. I've tried others and have decided the Pennzoil/BG stuff is the best. For the rear diff I've always stuck with whatever the oem oil is.

nycgps

iTrader: (1)

I changed mine to RP around 5K miles, now I just hit 15K today and it still feel pretty good.

there was a post somewhere about Redline and RP, I forgot who but he said he tried both rp and red. said that red is a bit rough when cold, once it warms up its perfectly fine.

PeteC

I changed to redline at about 5k miles, a little over 14k now and no trouble. Synthetic definately helps with early morning shifts when it's cold. I went with Redline over RP because I've got experience with RL (motorcycles) but I haven't heard anything bad about RP.

Search for the DIY on this (I think) it shows everything you need from redline. I ordered all of mine from Rosenthal Mazda, I could dig up the slip if you want.

swoope

iTrader: (5)

ike,
unless you have a rx8 owners manual.. or drive one all the time. this is the one time you need to be a mime...

beers

Ike

The RX-8 tranny calls for 75w90 and is GL-4, the same as most of my cars in the past and my current car. Synchros are sychros for the most part. In other words, lick me.

swoope

iTrader: (5)

damn you bastard. think it takes gl 5 in one or the other... but from my driving with rp 75-90 in both for 20k miles all has been very very good....

it really makes the tranny much much better.. and no cold weather here...

beers

Ike

GL-5 in the rear diff, GL-4 in the tranny IIRC... The synthetics do make it very smooth but your synchros are better off in the longterm with a little more friction IMO. It can certainly be argued one way or another but there's a reason why non synthetics are suggested for the tranny even in cars where synthetics are suggested for the engine.

swoope

iTrader: (5)

thanks,

dont start the syn war... you know we cannot use syn in our motors...

beers

zoned

Just had mine swapped out last week with RP 75w90 in the tran and diff. Feels alot smoother now. I'm a little upset because I had them change the oil as well, they spilled it getting the filter off and i can still smell oil when the engine warms up :-( I cant find any leaks so I'm praying to God that it's still burning from the spill.

StewC625

Ike:

Thanks for the good advice on the synchros - hadn't thought of that. That said, I will only have this car another 24000 miles and 25 months before she goes "home" to the leasing co. So ... not so worried about longevity ...