the manual recommends 75-80 for tranny. i want to use rp 75-90. what does the second number mean when it increase?

my guess are better protection?

Moved to Evo X Transmission.

its viscosity, (protection) the first number is vis, on initial startup(cold) second number is vis around operating temperature. lower vis can have better lubricating properties, and higer visc can have less due to its heaviness.....

not a proffessor in oil, so if anything is wrong feel free to correct.

The first number is cold weight, the second number is warm weight.

A lot of transmission fluid manufacturers do not make an exact 75w80. With oil or fluid it is often recommended to go with heavier warm weight rather than lighter, when you cannot get an exact match.

A lot of transmission fluid manufacturers do not make an exact 75w80. With oil or fluid it is often recommended to go with heavier warm weight rather than lighter, when you cannot an the exact match.

i learned something new. thanks.:dancebanana:

so its perfectly fine to use 75-90. thanks now i could go and change my fluid.

Heavier is usually not better for our transmissions by the way. I had Redline MT90 in my trans which is heavier than the stock oil. I was getting alot of grinds and it took a while for it to warm up. After switching to the lighter Redline MTL I got much smoother shifts and quicker warm up time.

The dealer installed mine. They confirmed 75w90 is fine. But do whatever. If you can't shift, fluid will not make a shit, imho.

i really wanted the stock diaqueen but dont want to spen 250+ on fluid. so im just going with some royal purple at pepboys.

i really wanted the stock diaqueen but dont want to spen 250+ on fluid. so im just going with some royal purple at pepboys.

You made the right choice. What people fail to remember is the manufacturer is ALWAYS trying to lower cost while maximizing profits...OEM = Devil.

Ask around the forums and see how many pro racers use Dia-Queen, that are not getting paid to say they like it.

^^ Lol. oem does suck.

what do you think of Royal Purple comparing with redline and amsoil.?
same quality?

^^ Lol. oem does suck.

what do you think of Royal Purple comparing with redline and amsoil.?
same quality?

I have only ever run Amsoil. I cannot attest to the performance or longevity of the other two. I have heard good things about both of them, but I have also heard mixed reports about Royal Purple not being the greatest for the long term. But like I said I have never tried either. In the end I am sure they are all better than Dia-Queen, imho.