Synthetic Vs. Dino Gear Oil

[Oldsragtopguy]

I want to change the gear oil in the 5-speed gearbox of my daily driver--1997 Nissan 200SX-SE.

It calls for a 80W90 GL-4 gear oil. I would like to put in some Sta-Lube Syn Go 75W90 full synthetic.

What do you all think?

 

[m2200b]

I use redline mt 75-90 thats GL 4 with good results at $8 qt. I'd quess the Sta Lube is group 3.

 

[TallPaul]

I'd go Redline.

 

[ewetho]

Heck Synthetic gear oil in a big rig will actually get you a longer warranty so there is one place that benefits are truly proven. Synthetic in the box is GOOD!!!

Redline MTL should be great too. I replaced Dino 80W-90 in a Swift on Redline recommendation to MTL and WOW it was good. Make sure you stick to that GL-4 spec as you can over-lube synchros with a GL-5. Makes some transaxles crash gears bad.

Redline would be wonderful in there.

 

[ewetho]

Should have stopped to mention Amsoil has a GL-4 80W-90 (or is it 75W-90 anyhow) that would be fantastic too.

 

[Oldsragtopguy]

On the label it says that it meets or exceeds the requirements for a GL-5 oil. It is my understanding that you can step up in GL number but not back.

How is it possible to over-lube the synchros, sorry if that is a dumb question.

Thanks for your opinions.

 

[Turbodriven]

I think the issue that you need to be careful of is the GL rating and that you do not use a GL 5 where a GL4 is asked for. There are some GL4/5 oils out there and you should be able to use those in either.
As far as I remember a GL 5 has a fair portion of sulphur Phos in it that can affect brass syncros.
Of course viscosity is important too.

 

[Wrehch]

At one time I was a diehard synthetic man. In the last couple of years though I have switched back to conventional oil for my gear oils. Since I drained the factory Mobil out of my medium and heavy duty trucks transmissions and rears and refilled them with TRC's 790 Sure Universal Gear Oil for the rears and 999 S&F Gear Oil for the trans my operating temps have dropped and the wear metal in my used oil analysis have gone down.

Somehow I doubt it's that the synthetic base stock is the problem and is probably that the conventional oil I am using just has a better additive package. All I know is the conventional works better for me in extreme duty applications. I do know one thing though. If you put some of the synthetic gear oil on your finger and rub them together hard a couple of times and then do the same with a similar weight conventional oil the oil film seems greater with the conventional and it's slicker to, not very scientific but it's just a observation.

 

[ffxfina3]

You need to be sure that your car can use GL-5 before you put something that is both GL-4/GL-5 in it. There are gear oils out there from Amsoil, Redline, Pennzoil (although I've never seen their's for sale), and others that are ONLY GL-4. GL-5 does NOT simply supercede GL-4. It is different. In my case (VW), I must use GL-4 only oils. I believe Toyota says either will work for their transmissions (don't quote me). The issue is that the GL-5 spec has some additives that can be corrosive to various soft metals. Be sure to know the specifics of what your car requires. If your car says GL-4 only, I'd go with GL-4.

 

[heathenbrewing]

Quote:

---

....I believe Toyota says either will work for their transmissions (don't quote me). The issue is that the GL-5 spec has some additives that can be corrosive to various soft metals. Be sure to know the specifics of what your car requires. If your car says GL-4 only, I'd go with GL-4.

---

I have a '06 Scion and even though the manual calls for GL4 or 5, and after a friendly battle with the service department, I found out that Toyota recommends GL-4 ONLY be used as it is much less corrosive thal the 5 series.

I think they put the "or" in there to cover themselves with any warranty issues. Im sure being able to stock just 1 gear lube makes more economic sense than having to purchase two.

 

[KBFXDLI]

Quote:

---

How is it possible to over-lube the synchros, sorry if that is a dumb question.

---

Not dumb at all...but be careful as some of the GL-5 lubes can be too slippery for synchros in a trans application. Try the Redline MTL or Amsoil 80w90.

 

[DWC28]

I don't believe the equipement needed to qualify for GL-4 is available any longer. Historically the EP additive treat level for GL-4 was about 1/2 of the level needed for GL-5. That was true for all base oil types. EP additives are sometimes corrosive to copper metals and that caused synchro problems, and OEMs recommended the GL-4 level.