Front and Rear Diff Oils Which one is best?

I am sorry to do this and dont even know where this should be, but I have read through pages of threads to find this answer. I have an 05 LGT 5MT with 135K on it and have changed it in the past with Mobil 1 75W-90 LS front and rear.

 

I have a noisy gear box and it shifts bad at high RPM's.

 

I have read Redline 75W-90 NS for front and non NS for rear, Royal Purple, Valvoline, special S from Subaru. It is maddening and all the different opinions.

 

Plain and simple, I want a quieter gear box that shifts better at high rpms, help!

Redline is what I run in my LGT.

I just swapped to 3qts of Redline lightweight shockproof gear oil and .8qt motul 300.. the tranny is so much quieter, and doesn't bind or stick when shifting anymore. I couldn't be happier. Some of the gurus on here highly regard this cocktail. As for the rear diff, motul 300 has worked well for me.

Subaru Extra-S

 

 

 

Why mix fluids that were never meant to be mixed when a Subaru branded product does the job better.

Subaru Extra-S

 

 

 

Why mix fluids that were never meant to be mixed when a Subaru branded product does the job better.

 

 

I agree 100%, but it was said that it is not as "quiet" or as durable for higher heat conditions. That only matters because I am moving in February to Texas. What's you're experience with the noise?

If you're tranny is so noisey that it bothers you, no fluid is going to fix that. You need a rebuild.

 

Same goes for synchro issues. ExtraS is known to smooth shifts by allowing the synchros to perform better. But it's still just a fluid. If you have mechanical wear and/or failure, no fluid will fix that.

 

 

As far as the heat, it's a full synthetic and it shouldn't be a problem.

I just swapped to 3qts of Redline lightweight shockproof gear oil and .8qt motul 300.. the tranny is so much quieter, and doesn't bind or stick when shifting anymore. I couldn't be happier. Some of the gurus on here highly regard this cocktail. As for the rear diff, motul 300 has worked well for me.

 

This is the cocktail your going to want to use.

 

In the years I've been here, this seems to help the most when you having noise and shifting issues.

 

You can thank BAC5.2 for this cocktail.

I just swapped to 3qts of Redline lightweight shockproof gear oil and .8qt motul 300.. the tranny is so much quieter, and doesn't bind or stick when shifting anymore. I couldn't be happier. Some of the gurus on here highly regard this cocktail. As for the rear diff, motul 300 has worked well for me.

 

I've put hundreds of thousands of miles on that "cocktail" to date.

 

There's nothing wrong with Extra-S, but I'll stick with what I've been using for the better half of a decade now.

i want to remember this

my buddy just went to redline , and im going to redline as well .... used it in all 3 of my bmw,s and always worked great .. great cold weather shifting. never had a problem with it ..

 

they make one without the friction modifer that goes into the trans , one with modifers goes in the diff

This is the cocktail your going to want to use.

 

In the years I've been here, this seems to help the most when you having noise and shifting issues.

 

You can thank BAC5.2 for this cocktail.

 

That's cool. Thanks because I have seen this more than once as a good combo. I found Redline at Summit which is about twenty minutes from my house but now I will look for Motul.

 

It's not that it is too noisy, it just is a noisy gearbox and they always have been. I remember the subaru guys at the race track calling these the "chatter box" and they always had some mystical secret gear oil formula they swore by. Being a Honda guy, we used motor oil for the gear box.

 

Thanks

This is the cocktail your going to want to use.

 

In the years I've been here, this seems to help the most when you having noise and shifting issues.

 

You can thank BAC5.2 for this cocktail.

 

Oh yeah, what about the 3 qts part? I thought the front took more?

You buy 3 qt of the redline and two qt of the Mutol 300.

 

put the 3 qt of redline in and top it off with .8qt of the 300.

 

the rear diff takes about .8qt of the 300 also.

 

Being a Honda guy my self, we used Honda manual tranny fluid in the race car and all Honda manual trannys. My son still has about 5 qt's left in the basement.

just changed mine out to straight motul. I'm pretty happy with it in the cold. Had negative temps the past couple nights, no issues. As far as going to Texas... not sure, but I've read good things about it in all temps. Just make sure its GL5 or higher and you should be good.

Oh yeah, what about the 3 qts part? I thought the front took more?

BTW... mine took 3 liters, not quarts, plus rear diff

You buy 3 qt of the redline and two qt of the Mutol 300.

 

put the 3 qt of redline in and top it off with .8qt of the 300.

 

the rear diff takes about .8qt of the 300 also.

 

Being a Honda guy my self, we used Honda manual tranny fluid in the race car and all Honda manual trannys. My son still has about 5 qt's left in the basement.

 

Which is basically 10W 30 motor oil! I was a line tech at a dealership for nine years and raced them and built them. Now I own a Subaru! Honda is a lack luster for me these days.

 

I am having trouble finding Motul locally and now it makes sense, thi must be that magic formula for that gear box.

 

Redline 75w-90 shock proof, this one right? http://m.summitracing.com/parts/red-58404

for front, 3 qts and Motul 300, .8 qts added to Redline and another .8 for rear. 3 redlined and two Motuls. Sorry to be so stupid but I only want to go up there once!

 

I can't find Motul anywhere locally.

AZP can get you the Motul.

 

You want Lightweight Shockproof.

just changed mine out to straight motul. I'm pretty happy with it in the cold. Had negative temps the past couple nights, no issues. As far as going to Texas... not sure, but I've read good things about it in all temps. Just make sure its GL5 or higher and you should be good.

 

Hmm.. I just swapped away from that.. I had a lot of gear noise, and the shifter was sticky. It was scary how much better the transmission likes the cocktail.

 

I have heard of people running straight Motul in STI's.. maybe it's a 6mt vs. 5mt thing.

Which is basically 10W 30 motor oil! I was a line tech at a dealership for nine years and raced them and built them. Now I own a Subaru! Honda is a lack luster for me these days.

 

I am having trouble finding Motul locally and now it makes sense, thi must be that magic formula for that gear box.

 

Redline 75w-90 shock proof, this one right? http://m.summitracing.com/parts/red-58404

for front, 3 qts and Motul 300, .8 qts added to Redline and another .8 for rear. 3 redlined and two Motuls. Sorry to be so stupid but I only want to go up there once!

 

I can't find Motul anywhere locally.

 

 

 

 

"3qts of Redline lightweight shockproof gear oil and .8qt motul 300"

That's for the tranny.

 

 

The rear diff get's .8 Motul 300

 

SO you need to buy

 

2 qt's Motul 300

3 qt's Redline lightwieght shockproof

 

You can buy it all from Mike at AZP.

Thanks Max, I had to run out before checking it, but with the car down because shafts being replaced, I needed to do something quick. Summit Racing is just down the road from me so I got Redline Lightwieght Shockproof straight for the front and ran Redline 75W-90 for the rear. BTW, Redline LT wt shockproof looks like Smurf Gammi. All they had in stock for the rear was the non NS, but having a sealed viscous coupling, I figured it didn't matter additive or not.

 

End result, the car shifts with unimaginable ease and smoothness. Glides into gear. As far as the noise, it definatley got quieter, actually kind of creepy quiet, only because I am used to hearing the whining under acceleration and feeling the notchiness of the shifter.

 

The rear fluid was golden brown, and I hate to admit it, it was the first time changed, ever. Very very little metal on the plug. The plugs came out no prob, despite being bathed yearly in salt for the past 8 years.

 

Now, I still have a "backlash-ish" noise while accelerating and is proportionate to the wheel speed, in or out of gear. The noise gets louder as the speed increases. I am suspecting Diff Carrier bearings? Is this a common ailment for these? I can only conclude this because the noise is related to wheel speed and gets loud when accelerating, quiets down when let off the throttle. I can't think it is the shaft as it is brand new and the noise was exactly the same before replacing it. The front wheel bearing have been replaced within the past twelve months and this noise was present before the replacement. That is why I fell it is carrier bearings. If so, that 6MT swap is looking real inviting for many reasons. I onestly have never had a vehicle with so many tranny problems and I wish I could take the credit of beating the crap out of it regularly, but I can't!