Transmission wear/was "Transmission Downshift"

[joe paco]

In four weeks, if this problem has gone from once, to occasionally and now regularly, it won't be long until the transmission fails.

As I said earlier, you can try a fluid and filter change, but my guess is this is not an issue relating to fluid/filter contamination. It's likely a problem with failed parts. When you pull the pan, if you find more than about a "dime's worth" of chips or metal powder, you need an overhaul.

Sorry to be the bearer of bad news.

sorry, Hib, but I don't agree with your "dime's worth" comment. You just described the majority of automatic cars on the road! I recently replaced fluid and filter in my 91, at 110,000 -simply because I didn't know the history of the car- and there was a film of light crud, probably aluminum dust, in the pan. the filter, too, was dark with whatever, also some aluminum "molecules." In the 3 yrs I have owned it I have not noticed the slightest symptom with it. certainly would not rebuild it based on the modest residues, even a dimes worth of chips.

saludos, joe

 

[Hib Halverson]

sorry, Hib, but I don't agree with your "dime's worth" comment. You just described the majority of automatic cars on the road! (snip)

saludos, joe

I like disagreement. It stimulates continued discussion and enhances the educational process.

Can you describe your background as an automatic transmission service tech? Also, how many Corvette automatics have you disassembled and inspected in your time as a trans specialist?

 

[joe paco]

I like disagreement. It stimulates continued discussion and enhances the educational process.

Can you describe your background as an automatic transmission service tech? Also, how many Corvette automatics have you disassembled and inspected in your time as a trans specialist?

\\well, excuse me, your majesty! I thought this was a forum, where non experts, like 90% of us, come to voice a stupid remark now and then!

let me clarify: nowhere did I suggest that my experience changing MY trans fluid qualified me as a trans speciaist. my comment should have been that I would not rebuild "my" trans, which i stated worked great, based on a criteria that you plucked out of the air. I fail to see how your condescending remarks are "enhancing the educational process."

you are likely well aware that I am not a trans specialist or service tech. I doubt seriously that you are, either. I am a retired GE QC engineer, and enjoy learning about my old Corvette, and was drawn to this forum by the sometimes friendly banter and good information I find -unaware that I would ever have to describe my extensive credentials if I should disagree with the assumed expert's opinion.

maybe this forum should dispense with member comments and let the self-ordained guru of all things Corvette answer the questions. even if you are totally right in your opinion, it is still an opinion, to most of us, and you could maybe use some training in diversity of opinions and resolution conflict -or how to communcate without insulting people.

someone started a thread, "not much participation at this forum." maybe you folks need to do some self examination.

 

[Hib Halverson]

\\well, excuse me, your majesty! I thought this was a forum, where non experts, like 90% of us, come to voice a stupid remark now and then!

Oh, please...spare me. I never said your remark was stupid. That's your interpretation, not mine.

you are likely well aware that I am not a trans specialist or service tech.

Actually, I not aware of that. I don't know "joe paco" from "jack". Your post said nothing about your background or expertise with automatic transmissions, and given your disagreement, I figured it was possible you had knowledge of the subject greater than mine, so I inquired. It might be you're not a trans expert, but, at the time I replied to your earlier post, it was just as possible that you own an trans rebuilding shop.

I doubt seriously that you are, either.

My background is: college degree in automotive service technology, former service technician, former engine builder, 20+ years as an automotive technical writer.

I am a retired GE QC engineer, and enjoy learning about my old Corvette, and was drawn to this forum by the sometimes friendly banter and good information I find -unaware that I would ever have to describe my extensive credentials if I should disagree with the assumed expert's opinion.

Come on "joe paco"...you think you are so special that you can make a critical statement then, when asked, not need to offer some insight to your "street creds" on the subject?

maybe this forum should dispense with member comments and let the self-ordained guru of all things Corvette answer the questions. even if you are totally right in your opinion, it is still an opinion, to most of us, and you could maybe use some training in diversity of opinions and resolution conflict -or how to communcate (sic) without insulting people.

You were not insulted.
You were questioned.
There's a bit of a difference. In my opinion, asking you about your background as a service tech or in transmission work is a reasonable request given your claim that my statement about "a 'dime's worth' of metal debris" is inaccurate.

Reality is that a dime's worth...ok...maybe a nickel's worth of metal in the bottom of the trans pan and a filter which is gray with metal debris is a symptom of a transmission which may be experiencing high wear rates or has had a component failure.

This particular transmission being discussed has already had a sprag failure and, I suspect, if the pan were removed, there'd be a fair amount of debris in it.

 

[Hib Halverson]

There was a thread running that Mac closed on automatic transmissions. It was closed because some thread contributors didn't like statements I was making. Why am I not surprised that my contributions to this site are not universally appreciated? :L

But....I digress.

I wanted to explain a little more about the wear processes in automatic transmissions because the OP of that thread wrote about an automatic which did not offer compression braking when manually shifted to second gear. "gmjunkie" diagnosed the problem as a failed sprag. I had commented that if the sprag had failed there's probably metal debris in the trans pan and that anything more than a dime's worth (or maybe a nickel's worth) of metal in the pan, it needs repair. When a sprag goes, it's going to put a lot of debris in the pan.

Typically there are four reasons, you can end-up with debris in the bottom of an automatic transmission oil pan

1) The ATF is failing. There are components of automatic transmission fluid that, when the fluid is overheated, oxidize. When this stuff oxidizes, the oxidation is partially composed of abrasive material. Admittedly, the ATFs of today (like Dexron III or IV or some of the reputable synthetic ATFs on the market) are more robust formulae and might not oxidize as easily, but it is still possible. When the fluid turns from red to brown, that means the fluid is oxidized and it may contain abrasive material which results from that oxidation. That abrasive material will harm the transmission.

2) Dirt or other contaminants enter the system via failing seals, faulty vent or contaminated ATF being added.

3) Normal (or perhaps abnormal) wear of friction materials on transmission parts such as clutch discs or bands.

4) Abnormal wear of transmission hardware such as bearings, bushings, clutch drums and so forth.

The bottom line is if you drop the pan and you find a dirty filter and quantity of brown, gray or silver powder equal to the volume of a dime or a nickel, you can get the transmission is experiencing an abnormal rate of wear.

 

[boomdriver]

I learned my lesson with a trans failure 15 yrs ago. That cost as much as a short block....

Since then, I find it TOO easy to do partial fluid changes to "freshen up" the fluid and keep the system clean. A drill pump with 1/4" hose dropped into the filler will allow you to suck out everything in the pan. If you want to get creative you can add a tap with a valve in the cooler line and actually add fluid as its being flushed out thru the line.
I also use syn fluid due to impressive fleet reports of greatly reduced trans failures in fleets that were changed over to synthetics.

Every so often take advantage of someones coupon and let a shop do a filter & fluid change. By maintaining the trans, there is a far better chance of it lasting as long or longer than the motor.

 

[Mac]

I've moved the contentious posts from John's useful thread here to Hib's thread as I secured John's agreement to allow the good diagnostic information in his thread remain rather than being deleted. If this thread goes downhill, it will be locked and perhaps more...

Hib, although I respect your knowledge and contributions to the CAC, sometimes you're a nuisance. Perhaps you should read my signature quote.

-Mac

 

[93Rubie]

Although, I am not any kind of master transmission technician I do hold ASE Master Certified Technician Status so I know enough to be dangourous. Also, I have a associates degree in automotive technology plus I have been employed full time as a service tech for 3 years, 6 months at a independent, 2 for Ford, and currently at Nissan. That being said, I tend to agree with Hib, most pans I have ever pulled and the transmission was operating normally, only had some grayish material on the magant, and not much of it. Any solid chunks of any size are a bad sign, fluid condition can be a telling factor as well. I would be alarmed to find any material in excess of the magnat area and being thicker than about the thickness of a dime or so. Most likey that is clutch material and IS a sign of wear. Not nessearyily impending transmission doom, but something to keep and eye on and prepare for. Transmissions are like anything else if you take care of it, more than likey it will last a long time, no care well not so long. My 2 cents worth...

 

[boomdriver]

Although, I am not any kind of master transmission technician I do hold ASE Master Certified Technician Status so I know enough to be dangourous. Also, I have a associates degree in automotive technology plus I have been employed full time as a service tech for 3 years, 6 months at a independent, 2 for Ford, and currently at Nissan. That being said, I tend to agree with Hib, most pans I have ever pulled and the transmission was operating normally, only had some grayish material on the magant, and not much of it. Any solid chunks of any size are a bad sign, fluid condition can be a telling factor as well. I would be alarmed to find any material in excess of the magnat area and being thicker than about the thickness of a dime or so. Most likey that is clutch material and IS a sign of wear. Not nessearyily impending transmission doom, but something to keep and eye on and prepare for. Transmissions are like anything else if you take care of it, more than likey it will last a long time, no care well not so long. My 2 cents worth...

I think the worst I ever saw in mine was some sludge like goo that was pooled in the corners. Never any solids of any size or consequence.
Being a hydraulics expert, tech and field engineer, I can tell you that ALL hydraulic systems wear. Its the amount of wear, and where that matters. When we would run a 10 micron filter and that would clog up too soon, we knew we had a problem coming. If we saw solids of ANY size in the return screens or magnets, we 'downed' the machined due to the impending failure and investigated. This is where oil analysis came in....those reports told us if the solids were chromium( cylinders & rods) or brass (pump rotary group) or steel (bearings) or aluminum (cases, housings). We knew where to look and what to look at.

A trans has parts designed to wear, such as clutches that are friction materials so some wear particles is to be expected. Seeing more than a dimes worth of solids should raise the red flags...

 

[Hib Halverson]

I was asked in a PM where the "dime's worth of metal" thing comes from.

Back when I was in college, getting my AA in automotive service technology, the instructor in the automatic trans class, taught that. After I graduated and went to work as a technician, whenever I serviced a trans and found more than a dime's or nickel's worth of metal powder or chips in the bottom of a pan, I'd tell the service manager, the trans needed more than just a fluid and filter change. They'd usually pass it on to the heavy line mechanic or the send it to a transmission shop. I don't work on many automatics nowadays, but once in a while I'll change an auto transmission's fluid and I always inspect the bottom of the pan looking for metal.

With an automatic trans that's in good condition and not near the end of its service life, you might have residue of the friction material on clutch plates and bands, but you should have almost no metallic residue. It is true that bearings, bushings and other metal parts will wear, but normal wear does not leave metal powder or chips. It very minute quantities of microscopic size particles which get trapped by the trans filter. Larger pieces (powder or chips) are too heavy to get trapped by the filter and end-up in the bottom of the pan. Any more than a dime's worth of that and you're getting close to needing an overhaul.

 

[boomdriver]

That pretty well says the same thing that I was attempting to communicate...



"... If we saw solids of ANY size in the return screens or magnets, we 'downed' the machined due to the impending failure and investigated. "



The slime or goo in the bottom of the pan was the microscopic wear materials that were to be expected, but any solid matter was cause for alarm. There is nothing in a hydraulic system that can tolerate metal particles floating around and/or abrading the very fine tolerances in the soft metals or seals. If you treat your hydraulics like your arteries and your heart. You'll be fine.

I had a $10,000 hyd pump explode once because the working cyls chrome rod had some microscopic scarring in the chrome that was pulling water up into the cyl each time it stroked. That was tiny bits at a time...next to nothing, but after 50,000 cycles, BOOM ! water had collected, condensed, eliminated lubrication and caused the thing to self destruct. In an event like that the chunks went back to the factory for analysis because the potential liability was huge...we always learned why, how and what to do to prevent it from happening again. Cleanliness & precision was ALWAYS the solution.