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

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.

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

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

Ed Pawlowski posted for all of us...

Isn't that Franks motto?

snipped-for-privacy@snyder.on.ca 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...

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?

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

Good ones don't last long on the lot.

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.

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.?

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.

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

I posted the link/info due to the conversation turning to synthetics so frequently.

Don't know about the USA - but generally we get the same product in Canada - and anything advertized as synthetic IS synthetic - but there are several ways to synthesize a lubricant - including from feed-stocks derived from petroleum - such as natural gas. If the molecules are broken down into base components, and then blended and reacted to produce a lubricating oil - the resulting oil IS synthetic

- whether the base feedstock is petroleum, natural gas, vegetable oil, or any other source. There ARE specific types of "synthetics" that some nerds and motorheads consider to be "more synthetic" than others.

- and some of them are NOT COMPATIBLE with some others, or with petroleum based oils - which in MY books makes the "unsuitable" for normal use - even if the "nerds" consider them superior.(Diesters vs PolyEsters vs polyalphaolefin vs alkylated benzenes vs phosphate esters,

Some are "group IV", some atr "group V" and some are "Group III" - with the "Group III" being the most controvercial as they are 100% petroleum sourced - with the feedstocks cracked from crude.

Many of the "nerds" consider only "Group IV" PAO oils to be "genuine synthetic" - and PAO oils have long been implicated in seal shrinkage and oil leakage. Diester and Polyester based oils are generally unsuitable for automotive and engine use -used in refrigeration oils, compressor oils, some greases, and jet engine lubrication. They are also implicated in seal incompatability. Phosphate esrhers do not mix or get along well with petroleum oils and are hard on most seals as well. Basically restricted to specific hydraulic uses. The poly-alkane Glycols also do not play well with othewrs - particularly petroleum based lubricants,and are hard on seals and finishes - used in hydraulics, compressors, refrigeration, and greases

"Generally" a GOOD synthetic oil for automotive use will be a combination of several synthetics to produce the required characteristics.

Good info... thanks!

Yes, your labelling laws much more closely follow the EU laws than the US ones in that regard.

--scott