I want to replace all my diff fluids with Redline and the spec section of the manual calls for GL 4 or 5 75W-90 for everything except the rear diff which says to use SAE 90. What the heck is SAE 90 and since I do a fair amount of offroading would I be better off with GL-4 or GL-5. Thanks and BTW this forum looks awesome for all oil related questions!!
Which Redline to use?
- Thread starter UKmyers
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Yes, UKmyers, I've been happy with Red Line products ... but I think they need to earn your business the old fashioned way.
I think their e-mail is [email protected] or something close to that. It should be on their website. Like satterfi said, just be sure to give them as much info on each application as you have available.
If I was in the UK, though, I might be tempted to merely go with Motul.
--- Bror Jace
I think their e-mail is [email protected] or something close to that. It should be on their website. Like satterfi said, just be sure to give them as much info on each application as you have available.
If I was in the UK, though, I might be tempted to merely go with Motul.
--- Bror Jace
Thanks guys I emailed their tech department with this info. I used to run Motul 2 stroke oil in my racing bike but that's my only experience with it. I am an american living over here in the UK so I can get pretty much anything I need from the states pretty easy. I am pretty sure I can go with 75W-90 but still curious what the differences in GL-5 or 4 would be? Thanks for the replies
UKmyers, use the "search" feature and search this gear oil section for discussion on GL-4, GL-5.
As I understand it, it's the amount of sulfur compounds used to activate the barrier additives is higher in the GL-5 (but also present to some degree in GL-4) so they tend to be more corrosive to brass/bronze parts.
If you end up using GL-5 in a pinch for a GL-4 application, swap it out twice as often. The corrosion takes place over time and needs moisture to take place. So, by swapping it out more often, you avoid most of the ill effects.
--- Bror Jace
PS - I thought you might be a Brit who didn't want to use a "Frenchie" oil. Motul is made in France, no?
Still, Red Line is a great choice ... if you don't mind paying S&H across the pond.
As I understand it, it's the amount of sulfur compounds used to activate the barrier additives is higher in the GL-5 (but also present to some degree in GL-4) so they tend to be more corrosive to brass/bronze parts.
If you end up using GL-5 in a pinch for a GL-4 application, swap it out twice as often. The corrosion takes place over time and needs moisture to take place. So, by swapping it out more often, you avoid most of the ill effects.
--- Bror Jace
PS - I thought you might be a Brit who didn't want to use a "Frenchie" oil. Motul is made in France, no?
Still, Red Line is a great choice ... if you don't mind paying S&H across the pond.
GL5 oils are specifically formulated for hypoid gears, such as rear axles, with low speed/high load characteristics and have more high pressure additives to prevent wear on the gear surfaces from harmonic vibration and extreme pressure loads (high torque/low speed) on these gears. These compounds are mostly sulphur compounds. Gl5 oils really only belong in rear ends and other hypoid gear applications. All other transmissions and gearboxes run on Gl3/4 oils.
Alex, Subaru specs a GL-5 oil in the transmission of the manual transmissions in their vehicles. No GL-4 spec there, but I suspect that Subaru specs a GL-5 because the transmission shares fluid with the front and/or center diff (don't remember if which or if both).
What to do in a case like this? GL-4 lubes shift much better, GL-5 lubes gives you crappy shifting... I would love to use Redline MT-90 in my Subaru because of the great results I've had in shifter performance in previous cars, but don't want to risk premature wear in the gears because of the oil or anything else...
What to do in a case like this? GL-4 lubes shift much better, GL-5 lubes gives you crappy shifting... I would love to use Redline MT-90 in my Subaru because of the great results I've had in shifter performance in previous cars, but don't want to risk premature wear in the gears because of the oil or anything else...
Dave
I have Redline 75W90NS GL5 in my Sube trans and shifting is significantly improved over the OEM fill, particularly when cold. I also have 75W90 (not NS) in diff and D4ATF in power steer. IMO Redline gear oils are about the best around But havn't tried Amsoil, Mobil or Schaeffers.
I have Redline 75W90NS GL5 in my Sube trans and shifting is significantly improved over the OEM fill, particularly when cold. I also have 75W90 (not NS) in diff and D4ATF in power steer. IMO Redline gear oils are about the best around But havn't tried Amsoil, Mobil or Schaeffers.
sprintman, thanks for the input.
Sounds like the thing to do is to use the 75w90NS in the transmission and 75w90 RedLine fluids, and the specs match. Hope to get around to filling my WRX with those fluids soon. 5k miles will be rolling around any time now...
Sounds like the thing to do is to use the 75w90NS in the transmission and 75w90 RedLine fluids, and the specs match. Hope to get around to filling my WRX with those fluids soon. 5k miles will be rolling around any time now...
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