Thread: Redline Heavy Shockproof 75W90?

this thread makes me wanna switch from heavy shockproof to mt90.. should i flush out the shockproof or can i just drain the shockproof and put in the mt90 and not worry about any remaining shockproof?

I only run shock proof on turbo cars. I run mt90 in my n/a cars.

You can just drain it. No flush needed. However, I'm still not convinced the Heavy has any real amount of sulfur in it that should worry us with our brass synchros.

Mt90 ftw

Man, I've been reading all the stuff on the net and especially Red Line website, they don't even mention what API-GL rating Shockproof has and the Tech paper started mumbling about 'durability not a major concern' then about LightWeight and SuperLeight Shockproof (:S) 'with little sacrafice in durabillity' and 'designed for use in competition differentials and transmissions'?

Nothing on the brass though. Doesn't sound safe. How can it be possible this is not mentioned by the big oil companies? :/

That is the weight I ran in my rear differential on my 240, I have and do run MT-90 in the transfer case on my sr20s. Every freaking SR20 transmission I have heard synchros will whine in 3rd gear. Not designed to haul 220+ lb fat asses around all day.

Are all gears brass like? I learned that 3rd gear seems a little small for what it needs to hold but why brass anyway? Brass doesn't seem to hold up?

Who said any gears were mad of brass?

3rd gear is not too small. The gear stacks are too long, unsupported, and bend outward under load. 3rd gear is in the middle.

Brass holds up just fine, and has real good frictional properties making it a great choice for synchronizers.

*withdraws prod stick* I'm not seeing why the industry invents brass synchro's, then GL5?

There is something with 3rd gear right? Reliable source told me gearbox holds 170WHP for a decent while, anything beyond that means replacing gearbox?