trans fluid redline question

[nj kiter]

i earned scoobytuner credits, and figured that i could change out trans fluid. i was thinking red line gear oil 75W90NS, would this help my trannys shifting? my 5 gear sincro grinds on the top end, will it do away with this? also can it be used in the diff too. thank you in advance

[VD5505]

I always used RedLine Shockproof Gear Oil and it worked GREAT, my car use to grind just a little bit in 5th and that did help that little grind go away, you will have to buy 4 quarts for your tranny but it only takes 3.7qt. RedLine is really a great product

[nj kiter]

and the 75W90NS will work in the diff too?

[jed344]

i have that kind in mine still will sometimes grind a tiny bit in 5th but otherwise A+ from me

[man show]

I got this information here: Red Line Oil

75W90
Our most popular gear oil, this is the preferred product in nearly all car and light truck differentials, both conventional and limited-slip. 75W90 is preferred for most racing applications. It contains friction modifiers which are recommended for limited-slip units. 75W90 Gear Oil can be used in many transmissions and transaxles; however, other Redline lubricants have better frictional properties for rapid synchronization. Exceeds API GL-5.

75W90 NS
This GL-5-type gear oil doesn't contain the friction modifiers for limited-slip hypoid differentials. This makes the transmission synchronizers come to equal speeds more quickly, allowing for faster shifting and much easier low-temperature shifting. It can also be used in racing limited-slip differentials where weak spring design causes too much wheel spin.

Redline 75W90 NS is meant for the transmission - you'll need to order 4 quarts (STi would need 5 quarts)
Redline 75W90 is meant for your rear differential - you'll need to order 1 quart

[pzr2874]

Originally Posted by nj kiter

and the 75W90NS will work in the diff too?

Don't use any Redline in your rear diff. Just use Mobil 1 or Subaru's "S"

[nj kiter]

ok so here is what i am thinking the 2004 sti's tranny holds 4.3 quarts right? assuming i am correct i am thinking one quart of redline superlight shock proof 75w90, and 3.3 quarts of the 75w90 ns. do you guys think that would be a good combination. also is that the right shockproof, the super light, because they say it is not recommended for syncro trannys

[pzr2874]

3 NS and 1 lightweight (.7/.8)

[nj kiter]

huh? i am a noob to tranny fluid in total the 2004 sti holds 4.3 qurts right, or am i wrong. also it is ok to mix those two together, and which one do i use the superlight, lightweight, or heavy weight.

[VD5505]

thats all i used in my tranny for 3 years is straight shock proof redline oil and ran perfect i never ever had one prob with my tranny

[man show]

I'm a fan of Redline fluids (I've used their 5W30 oil in my engine, 75W90 NS in my trans, and 75W90 in my rear differential), but I'm still not completely convinced that any kind of Shockproof should be used. I would use only 75W90 NS in the tranny because that's what's specifically formulated to be used in there. Since you have an STi, you'll need five quarts of it to ensure your transmission is full - it should hold four complete quarts and a little bit from the fifth quart.

[c2bcoolwrx]

I have used Redline 75W90 NS and Motul Gear300 75W90 in my tranny. The redline was good, but the Motul Gear300 has been my favorite.

You can get it here if your interested: Gear300 75W90 Turn In Concepts