What's so special about gear oil that it's 70 bucks a gallon?

[Ed Pawlowski]

Better living through chemistry!

[trader_4]

You see this on lots of those gear head forums. Where they will spend $$$$ for super premium products that make no sense without even understanding why. I've been at the BMW dealer parts counter and seen people come in to buy oil at $8 a qt, they believe you have to use only BMW antifreeze, etc. As long as it meets the spec recommended by the auto manufacturer, it will be fine.

The 75 and the 90 spec the viscosity at the cold and hot ends of the working temp range and both types have to meet it. Synthetic may exceed it, hold that viscosity profile over a wider range, but it's not going to be an issue for your application.

[Stormin' Norman]

If it were me and I were committed to changing the oil before fixing the problem, I would simply replace it with what is recommended by the manufacturer, probably a non-synthetic Gl-4 gear oil of the proper viscosity.

The rationale being, if you end up taking it to a transmission shop because of internal issues with the transmission, they are simply going to dump your oil and refill the unit with fresh oil when they have completed the repair. In other words, since you have no idea what is wrong with the transmission, your expensive synthetic could end up at the oil recycler well before the end of it's usable life.

I would focus on diagnosing the issue before replacing the oil, but that is just me.

[trader_4]

And Amsoil and Royal Purple are recognized brand names, that the gear heads go gaga over, so you pay more for them because they can get it, just like with other products. You can find typically find synthetics from other manufacturers that meet the same specs, but cost less.

[trader_4]

I just said that in another post. You see that in those gear head forums a lot. I just saw a thread where people in a BMW forum where someone was asking where to source replacement vacuum hose because they needed some and the BMW product was too expensive. To replace even a modest amount of it, if you ordered it by the BMW part #, it would be $75+. Even aftermarket sources, if you order it by the BMW part numbers, it's probably still half that. Yet some gear head chimes in that "if you can't afford to buy some vacuum hose at BMW, you shouldn't own the car". You can get silicone hose of the right diameter for less than $1 a foot.

And when it comes to fluids, some of these gear heads must think that every manufacturer has their own refinery or chemical factory.

[Scott Dorsey]

That's a function of the VI additives, not the base oil. A higher end oil is apt to have better and more stable VI additives. This means that after five years in the transmission, it's apt to remain a 75W90 oil, whereas the less expensive oil probably won't be.

Now, in extreme cold, the synthetic might well be thinner. Remember that it's a 75W90 oil meaning that two viscosity measurements are made at two different temperatures. Once you get outside those temperatures, the behaviour of the different oils will not be the same. This isn't an issue here in Virginia but it might be a very significant one in Maine.

These days there are a lot of conventional oils that come very close to the stability and quality of the synthetics, and in the US most of them can be sold legally as "synthetic" even though they are not really. This makes the labelling very problematic unless you look very carefully. The Castrol Syntec 10W-30 can't be sold legally in Europe as a synthetic oil, but the Syntec 10W-40 can be. If you look carefully at the type approvals on the label you can see this.

--scott

[Willy]

Oh, if you are trying to make this vehicle last forever, quit being such a tightwad and buy the Amsoil.

[Tekkie®]

Ed Pawlowski posted for all of us...

Isn't that Franks motto?

[Tekkie®]

[e-mail] posted for all of us...

Clare, I saw a Ranger on a car lot. I called a couple days later to see if I could take a look at it. SOLD...

[Tekkie®]

trader_4 posted for all of us...

That sucks

I want gen u ine stuff.

[Bram van den Heuvel]

I'm going to agree with you that they say a LOT on those forums that "if you can't afford to pay X for Y, then you shouldn't own the car".

But what they fail to understand is that a question ASKING what's different about Redline MT-90 75W90 GL-4 gear oil that makes it worth twice the price of some other 75W90 GL-4 gear oil is NOT a question about price.

It's a question about what's different besides price.

All they see is "price" because everyone understands numbers. What they don't see is the question about what is different that warrants that price.

Sometimes the answer to price performance questions is that the performance merits the price while other times there's a lot less performance than there is price.

It's a ratio - but without knowing what's different - nobody can make an intelligent decision on the price-to-performance ratio.

I'm not sure I understand yet what's different in the Redline/Amsoil/RPurpal 75W90 GL4 because I live in a warm state where the

75W isn't my issue but the 90 is. 90 weight is 90 weight. If it's 90 weight for more years, then that's OK. If it's 90 weight at tremendously hotter than normal, then that's OK.

But that was the question, which I now can hone because I didn't know that the expensive oils were synthetic.

If a synthetic oil "lasts longer" at 75W90, well, that's worth something. I'm only asking what's the difference.

[trader_4]

That's the biggest difference, that synthetic last longer and you can go longer between oil changes. BMW uses synthetic and was at 15K for oil change interval for years. More recently they backed down to 10K, presumably because they decided they were pushing it too far.

[Bram van den Heuvel]

Clare, can I ask a question about "temperature"?

Today I took a drive to San Francisco, where I took some friends on a tour, so the car was fully loaded and I could smell the asbestos (or whatever that smell is) on some of the very steep hills where I had to stop and then slip the clutch when starting (as cars were behind me).

While the clutch worked for two hundred miles getting there and getting back, at some point during the high-stress hills, the clutch pedal sort of just stuck at the low position a couple of times. What would cause that?

Also, at about the same high-stress time, it was hard to get into first and second gear. Like really hard.

Yet, the hundred miles there and the hundred miles back and the fifty or so miles in and around the city in lower stress situations, the clutch worked ok.

Could that be the fluid? Or something else?

Given the fluid I put in will definitely be GL4 and 75W90 (as per Toyota specs), would a synthetic matter for this issue?

Or do all transmissions do that?

[Scott Dorsey]

A leak in the hydraulics. Check the master cylinder first, then check the slave. If you aren't changing your brake fluid every year or two, now might be a good time to try doing that. My inclination would be to pull the piston from the master and check the condition of the seals too.

That could be because the clutch isn't completely out, or it might be for some other reason. Could be sticky synchronizers.

One of the things about SOME of the synthetic oils is that they have strong solvent properties. I know this is the case for the Royal Purple, but I cannot speak for all the others. If your transmission is gunked up from varnish due to years of not having changed the fluid properly, the high solvent oil may dissolve some of that. It's possible one of the "Toyota Guys" is thinking that your synchronizers are gunked up with sticky goo and that a synthetic oil might help free them. And that is likely not too bad a plan. $50 worth of oil is a lot less expensive than dropping the transmission to look inside. However, your clutch issue would make me suspect the clutch hydraulics rather than the synchronizers. Even so, you should be changing fluids on a regular basis and it won't hurt to start now.

--scott

[clare]

Good ones don't last long on the lot.

[clare]

Sorry to take so long to get back to you. I had a nice stressless vacation out on "Ontario's west coast"

I believe you have a hydraulic clutch. The clutch sticking to the floor is a linkage problem, totally separeate from the treans fluid. Have you ever flushed the hydraulics? If not might be a good idea. Specified every 2 years - every 4 is pushing it. Many cars never have it changed. Could have a master problem. Could have a slave problem - could also have a release bearing collar issue (not related to the hydraulic fluid)

When it was hard to get into first and second, did reverse work? If the clutch is not completely disengaging or the pilot bearing is hanging, it will be hard to shift, and it will "clash" going into reverse.

[83LowRider]

Regarding synthetics in general --

"the AAA study didn?t go light on the research and took a comprehensive look into all the factors involved."

?AAA found that synthetic oil outperformed conventional oil by an average of nearly 50 percent in its independent evaluation, offering vehicles significantly better engine protection for only $5 more per month when following a factory-recommended oil change schedule.?

[Bram van den Heuvel]

IMHO, motor oil is one thing, gear lube is another.

Worse - the GL rating (e.g., GL-4 or GL-5) isn't relevant to synchronized transmissions.

I've come to the conclusion that all I know for sure is that Toyota recommends 2.7 quarts of GL-4 or GL-5 75W90, and that's all that matters since the rest seems to be marketing in that I can only find a single study on the net that goes any deeper than that for transmissions.

[Scott Dorsey]

This is good but... what does "synthetic" mean? A lot of the oils sold as "synthetic" in the US are not in fact made from synthetic base oils at all, just very highly purified ones.

And as it is, conventional oils vary considerably in their protection, because the additive packages vary so much.

--scott

[trader_4]

e:

IDK how much they actually vary, assuming they meet the same API standards. That sets a floor under how they perform. And typically vehicle manufacturers use that to specify what oil can be used. Though I think some years back some manufacturers started specifying a spec ific brand. How much that's based on how they actually perform and science versus marketing BS, IDK.

And then you have to wonder about auto manufacturers pushing the oil change mileage and what's really behind it. BMW for example went to

15K many years back. More recently, they backed it down to 10K. They also included free oil changes as part of their included services. So, who was the 15K really benefitting? The engine and long term owner or BMW not having to change the oil for free as many times?