automatic transmission failure question

er, you don't need to /have/ an explorer - you simply need to look at one.

untrue, both as a matter of fact and as a matter of comparison.

untrue.

<...>

there's a fundamental knowledge gap with everything you're saying. i don't see you being able to bridge it, so i'm done. have a nice day.

This from the guy who doesn't understand the concept of viscosity index and thinks that 30-weight oil is "always thicker" than 10w30 oil at high temperatures.

You really need to get a clue. Lots of clues, actually.

Generally speaking it IS. Not by any great amount, but it is slightly thicker. At least the lab tests at Texaco showed that. Maybe liquids flow differently in YOUR lab?

eh? i don't know who you think you're talking with, but you /do/ know that " snipped-for-privacy@privacy.net" is a generic anti-spam address that /lots/ of people use don't you?

backatcha big guy. but because i simply can't resist taunting idiots, why don't you tell the class what you make of this:

thanks.

Oops. I owe you a very sincere apology. There is someone who just goes by "Jim" that pops up every time a .tech thread gets cross-posted with a .makers.honda thread, and I had you and he confused.

That was 100% my mistake, and I do apologize.

Since I mistakenly dragged you into this, I feel I owe you the background. The last time this came up and I pulled up an oil company's spec sheet that showed their 10w30 was slightly thicker than their own SAE 30 even AT 100C, "Jim" dismissed it as "believing glossy advertising" and claimed that an SAE30 weight would always be much thicker than a 10w30,"especially" on the high side of 100C. The chart you just linked agrees with my claim, which is that since Xw30 oils have a viscosity index much higher than the average SAE 30 oil, they will match SAE 30 at 100C (where the spec defines the "30" in an Xw30) and then as temperature continues to increase the Xw30 will actually maintain a greater thickness than the SAE 30. The viscosity lines clearly CROSS at the 100C measurement point, so above that point (until somewhere > 300F where the VI improvers start breaking down and the oil itself begins to oxidize) the 0w30 becomes THICKER than the straight SAE30. NOT thinner. Granted, that's not shown on this chart, but its what happens.

Now, rather than just calling each other morons (which I admittedly feel like after that mistake...), could you possibly explain your claim that leaf spring suspensions, in general, have more lateral deflection than other designs? I agree that *particular* implementations may have excessive lateral movement, but in general I've always found that panhard-rod/trailing arm axle designs are more prone to slop (due to the large bushings involved) than most simple leaf-spring designs. And even when the slop is eliminated (heim joints, etc.) there's a residual issue of the fact that the axle makes a large radius arc relative to the vehicle centerline as the suspension extends or compresses, giving rise to the "head toss" handling quirk that coil-sprung trucks like Jeep XJs and TJs sometimes exhibit. In fact, Dodge is rather vocal in the automotive press about how much work went into the coil spring rear suspension of the new Ram 1500 to enable it to match the stability and load-carrying capacity of conventional leaf suspensions... work that was required BECAUSE of the lateral rigidity and inherent body-roll resistance of leaf spring stacks, which were lost in utilizing coil springs.

You apparently have considerable trouble remembering what you have said and what others say to you, as well as your obvious difficulties with keeping track of who people are.

No one ever claimed that 30 wt oil would always be much thicker than

10w30. You just made that up. What was said is that there is an allowable range for 30 wt classification at 100C temp. The petroleum refiners tend to produce a product that is at the thin side of the allowable range when they produce 10w30 and when they produce a straight 30 wt oil it tends to be made at the thick side of the allowable range. That doesn't mean you can't find any 10w30 that is thicker or a straight 30 wt that is thinner, just that that isn't the norm. ` Also, no one said anything about one "being much thicker". Both 10w30 and straight 30 wt have roughly the same thickness at 100C. But roughly the same is not what many people think it means. The range for SAE20 is something like 5.6 to 9.3 and the range for SAE30 is 9.6 to 12.5 and range for SAE40 is 12.6 to 16.3 and so on. It is quite possible for a straight 30 weight oil to be closer in thickness to a 10w40 and a 10w30 to be closer to a straight 20 wt oil at 100C temp. And in fact that is exactly what often happens due to economics of manufacturing mineral oil and the need to meet fuel efficiency standards.

Your only attempt at a response to the above was to produce an advertisement for a synthetic oil and claim that the specifications contained therein mathematically disproves the statement made specifically about petroleum based oils. In fact your article was irrelevant because it didn't even mention petroleum based oils and it contained nothing even vaguely resembling a mathematical proof of anything.

-jim

no problem.

to an extent. but it's a bit more complicated than that. viscosity is not lubricity so exclusive focus on that isn't sufficient. what you need is an oil that is stable not just at temperature, but at high shear rates too. from what i understand, an odd assortment of base oil compounds with branched chains, aromatics and inconsistent compounds, like you have with "single weight", can't be relied on to do that in a high shear hydrodynamic situation without all kinds of oddness like cavitation and shear thinning.

ok, we need to separate marketing spin from reality. reality is that leaf springs are CHEAP [the primary objective of anything detroit], simple and kind-sorta work ok with low lateral loads, low speeds, and where unsprung weight doesn't much matter. but if any of the above are a factor, they suck. aside from the more obvious problems with things like axle rotation on torque, the lateral issue is the same kind of problem you can have with a saw blade. the frame remains rigid, but the thin blade [elastically] buckles and bucks if load, speed, angle etc., aren't just right. that same elastic buckling is what accommodates lateral movement on leaf springs. add to that worn pivot points and you have a real stability problem.

as for being "rather vocal", all this stuff about having to spend money to "design" a suspension system is just sheer effrontery and b.s. there is nothing new in what they're doing. if anything, it's decades behind the times. i've been to europe many times, and over there, they've had heavy and light trucks with independent suspension, not a leaf spring in sight, for what seems like ever. even the last hold-out of european backwardness, the land rover, finally got with the program in the 80's. here /we/ are in the naughties, 30-odd years later, and we're making out like it's new and complicated??? that dude, is ridiculous.

these guys know what they're doing.

Agreed.

reality is that

Well... "suck" is relative too. Almost any leaf spring implementation that can carry a 1/2 ton class truck or SUV will have a master leaf that is on the order of 3" wide and 3/8" thick solid spring steel, and the whole spring stack will be about 1.5 inches tall with the master leaf only acting alone over a span of 3-5 inches longitudinally. So you're really talking about "bending and buckling" something that quite frankly is NOT going to bend or buckle under the loadings that the tires can apply to it.

But my real disagreement here is that we have to compare leafs and their shortcomings to real-world alternative rear suspensions made with oversized bushings, sub-optimal geometry to avoid impinging on interior space, and rather flexible stamped steel or cast aluminum members that compare rather poorly to the leaf spring stack in terms of rigidity. FOR THE MONEY, leaf springs quite often suck LESS than alternatives, which was my point. IMO that was a big part of why the Honda Ridgeline hit the market with a dull wet thump- it was all road manners and no hauling ability. Were there some horrible leaf spring designs? SURE! Look at any GM midsize car of the 70s that used leaf springs with long single-leaf sections and not enough asymmetry to overcome axle torque (Nova, for example). Those are the springs that gave rise to a whole aftermarket of traction bars and other band-aids to try to get them to work as well as better designs.

Of course leafs don't play with independent rear suspensions which are becoming more common even on trucks, but that too is fuelled largely by marketing hype. Solid axles actually have some favorable handling characteristics (such as roll center) that get ignored because they're considered "ancient" by the advertising types. If you want a truck with an acceptable combination of weight hauling capability, drivetrain strength, low cost, and acceptable handling, then solid axles (with or without leaf springs) are actually near the top of the list of candidates.

Can they ever achieve the ultimate handling of a good independent rear suspension? Of course not, or we'd see solid-axle Ferraris. Can an independent rear suspension ever equal solid axle load carrying ability and longevity under heavy loading? No, not at any reasonable cost (or else we'd be seeing IRS on cement mixers. The pickup market falls in the middle where either solution can be made to work with some compromises.

The innovation here is combining leaf springs with a solid axle in this application, not IRS. Its the first non-leaf-sprung solid axle truck since the '72 GM pickups, which were notoriously poor handlers when loaded, although much better than leaf-sprung trucks when empty. Its the combination of load carrying ability and stability with unloaded manners that is new here. IRS ala Unimog or Humvee would be cost prohibitive and unnecessary. I agree they're just crowing about what someone should have looked into about 15 years ago, but as you said- COST is an engineering driver as much as function in many cases.

At any rate, thanks for the discussion.

Wonder if he ever found out what the problem was????

It's all archived for anyone to read, and anyone who chooses to do so will quickly see that very little of what you said in this post was true of the original discussion (for example, no one limited it to non-synthetic oils). And you *still* can't seem to recognize the difference between advertising and specifications.

What was the question again??? :-p

I limited my statement to non-synthetic oils. I did so repeatedly both before and after you said it was not true.

Ha Ha Ha that's a good one. You are very funny guy.

jim beam wrote:

If you are referring to petroleum based oil your understanding is not correct. The fact is that a single weight (monograde) oil is well suited to handle the high temp high shear requirements of modern oil standards. In fact if you research the origins of the current standard for high temp high shear you will find the standards for multigrade oils were arrived at by sampling all the monograde oils being sold and the standard for high temp viscosity was set at the 95 percentile of what tests found for monogrades at that point in time. That is, almost every single weight oil (95% of them) they tested was better then the minimum standard set (Viscosity at 150C and 10^6 s^-1 shear rate) for that particular weight range. Very few of the multigrades exceed the standard for high temp viscosity by much but almost all monograde oils do. And this only applies to 20 and 30 weight oils . A 5w40 or 10w40 is even required to meet the same standard that the straight 40 wt must meet. A

10w40 is only required to have the same viscosity as any common monograde 30 wt to meet the the high-temp-high-shear test standard. Look it up if you don't believe me.

The problem of the petroleum based oil becoming very thin and weak at high temp and high load conditions is and always has been a problem related to the viscosity improvers used in multigrade oils. The polymers that are used to improve viscosity start to break down at temperatures above the standard 100C temperature at which viscosity is measured for establishing the grade. What that means in simple layman's term is that lots of engines were being damaged when drivers attempted to haul their boat up a hill on a hot day or when their cooling system failed for some reason at highway speeds. This was a known problem with petroleum based multigrade oils. But since the oil companies and automakers had no known chemical solution for the problem with petroleum based oil (other than the unacceptable one of using straight weight oils) the problem was kept very quiet for many years after multigrade oil was first introduced. Then about 15-20 years ago when the technology was sufficiently advanced the problem was finally addressed by changing the standards. That change is one of the main reasons why you now hear so many claims on how modern oils are so so much better than they used to be. That is because what was in most cars on the road 30 years ago was really crap if your engine ran hot for some reason. Even today they have no means to economically make the viscosity of 10w40 a good as straight 40 wt. oil (at the 150C temp and 10^6 s^-1 shear test) and that is why the standard for viscosity for those multigrades are less than it is for the 40 wt. monograde. It is not until you get to the 15w40 oils that the high temp viscosity requirement for multigrade is the same as it is for straight

40 wt.

The irony of all this is that the oil companies have used this as an advertising ploy. Nowadays, they claim that their multigrade oil is specially formulated for high temp high load operating conditions. The implication is that because the straight weight oils are not specially formulated for high temp high load they must not be as good under those conditions. Apparently through this sort of advertising they have been successful at leading many people to leap to this false conclusion.

-jim

The tranny QUIT on him. No-go... I wonder IF he found out why.

but they don't. really.

that's completely untrue. think about it - there is no way a "boxed" structure is as rigid as a triangulated structure. it simply cannot be.

i don't think it's about "reasonable" cost - earth movers don't use leaf springs and they're /way/ bigger than cement mixers. if you want my opinion, based on my having traveled a lot and seen other peoples solutions, i think it's simply that we have a kind of bizarre cultural inertia here that simply doesn't /believe/, hence we don't even try.

but it's not cost prohibitive. and what cost is safety? the exploder, leaf sprung, is a classic example. how many people do we have to kill before we start looking at the big picture?

And are the basis for Nascar Sprint Cup rear suspensions.

which achieves precisely nothing and is no indicator of quality or lubricity or stability.

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you're mixing friction with non-fact. you need to read something other than an amsoil website.

f*ck - i really can't be bothered to argue with such bullshit.

mysterios get no info fr me

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