Synthetic Transmission Fluid

[mazdaspeedjamie]

I know this has been discussed several times over (I love saying that) but let me bring it up again. I am at 30,000 miles on my 03.5 MSP and I want to swap to synthetic transmission fluid. I have been looking at several name brands: Redline, Royal Purple and Mobil 1. A friend of mine switched to synthetic on his MSP a while back and the shop he took it to used Redline Light Weight "Shock Proof." The only problem I have with that product is that it does NOT have friction inhibitors and from what I have been reading I thought you needed those for the LSD!? He has had no problems and I have been told that the type of LSD used in the MSP doesn't require the friction inhibitors. Redlines normal synthetic 75W-90 DOES contain friction inhibitors, however, overall the "Light Weight, Shock Proof" seems to be the better product. The only reason I am looking at Mobil 1's synthetic transmission fluid is because I am already running their synthetic motor oil. But, as of yet, I haven't met anyone who is using their transmission fluid. Again, please give me your opinion and feel free to back it up with facts. My car is stock except for an Apexi Turbo Timer (auto timer).

 

[BOOSTR]

I've been using Mobil 1 75W90 for some time now. Just added it straight in, no friction modifier used or needed. If your happy with the way your car shifts, save the money and just put the dino transmission fluid in. I wasn't happy with the way mine shifted and wouldn't go in to reverse all of the time. After the switch, shift feel was better and it always goes in reverse the first time. It holds up better under the extreme use mine sees.

 

[ms03protege]

I've been using the Redline 75W 90 synthetic fluid for about 10k miles and have been happy with it. I noticed a difference such as smoother shifts and easier engagment. I would recommend it.

 

[ChopstickHero]

I have been using Redline MT90 (75W90) for the last 10k miles as well. Noticed a big difference after the switch. You will need 3 bottles of it if you switch. I have read that the Lightweight Scockproof is not suited for synchro-type trannys (like ours). But have seen some people use them on this board.

 

[Perro del Sol]

I use MT-90 in all of my Mazda's, both 6's and the MSP. My wife even noticed the difference in the smoother shifiting, it says a lot about a product, when someone with no knowledge of the mechanical workings of a tranny can tell you they feel a difference in the way the cars shift.

 

[Stormtrooper77]

I'm going to give the Pennzoil Synchromesh a try. The Redline is just too expensive.

 

[mazdaspeedjamie]

Red Lines E-mail reply reference their products

Hey... here is a copy of Red Lines E-mail response to my transmission fluid question:


Jamie,

Thank you for contacting Red Line Oil, in your Protege transaxle I
would recommend the MT-90. The ShockProof gear oils are designed and
better suited to racing and some speciality applications, they
contain a friction modifier so can be too slippery for synchros,
their flow characteristics are better suited to moderate and higher
temperatures and due to their very unique appearance wouldn't be
advised while under warranty.

Regards, Dave
Red Line Oil