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Amclaussen
User Rank
Platinum
Re: taurus subframe mounts
Amclaussen   4/19/2012 4:48:59 PM
Even when many automatic transmissions are prone to failure by diverse mechanisms, one of them being using a too small desing for the weight/power of the car, one thing I have seen in common is the very low maintenance they receive.  This could be because of some myths surrounding them, like the one that says that if you neglected to change the Fluid for a long time, an ATF change will make the transmission fail inmediately, or start a huge spill... there is a little bit of truth in this belief, but one thing is that an abused and neglected auto transmission that has formed a lot of sludge inside will probably start to leak profusely because of long degraded seals and gaskets (the sludge was actually helping to seal), an another thing is to delay a proper fluid change because of the false belief that ATF is "eternal" or "for the life of the vehicle".

And talking about the 'proper' way to change the fluid, is to remember that most transmissions do not have means to drain all the old ATF.  This means that the usual "Quick-and-dirty" Oil Change places will only drop down the transmission pan, which removes only the old ATF in the pan, frequently less than half the total contents of ATF of the whole transmission.  The Torque Converter can hold anything from 50% to more than 60% of the fluid, but in most cars it lacks any plug to remove the trapped fluid.

The best way to perform a proper and complete ATF change, is to first remove the transmission pan in order to change the trasmission filter.  Then the pan is cleaned, reinstalled and sealed with a good quality RTV, the same quantity of ATF that the pan was holding is replaced with new ATF.  THEN, the hoses going to the transmission oil cooler are disconnected and routed to a large translucent container, previously marked in quarts with a permanent marker.  Prepare a small table to place several extra quarts of new ATF, already opened and ready to be dumped into the level stick tube thru a large funnel.  Now, start the engine and put the transmission into drive (the car has to be properly blocked and parking brake applied). As soon as the engine starts, the transmission hydraulic pump will start to move the fluid and discharge it thru one of the hoses.  You have to keep pouring the new fluid as the old one is being pumped out, that's the reason for marking the receiving container, so that the proper level of fluid is maintained since it is important to avoid ovefilling or running too low. It helps to cut a short (4") lenght of transparent tubing and to use a lenght of transparent vinyl tubing in order to actually see the old fluid as it is discharged into the container.  By putting a white piece of cardboard illuminated with a 100 watt light behind the tubing along with the short lenght filled with new fluid, it is very easy to see the slightest change in color, which will turn from a dark brick red color to the transparent light cherry red of the new ATF. In my car, which holds a total of 9 quarts of ATF, after putting the initial 4 quarts into the pan, an additional 9 quarts were circulated in order to completely flush the whole transmission. From quart number 8 the color was almost as transparent as the color of the new fluid, by quart number 12 the color was practically undistinguishable from the new fluid.  By contrast, the color of the old fluid in the pan was still red, but very dark.

I forgot to say, there is a small magnet on the bottom of the pan, which will almost certainly look as a sea urchin, full of spines formed by metallic dust from the wear of the clutches and other parts. A  teaspoon full of metallic particles is usual after several tens of thousand miles of driving. It also helps to have an assistant to put the transmission tru all the positions during the flush, Reverse, drive and every other, to help in washing out the old fluid. Some mechanics even add a small bottle of "Oil System Cleaner" like the one used to clean the engine, but it is only necessary if the ATF was not changed in a very long time.

By performing a complete ATF flush and filter replacement every 25.000 miles, the transmission will last for the life of the vehicle, often more than 100.000 miles without failure.  Take note that Chrysler Vehicles use and require a different kind of ATF (called "ATF+4) and not the more common "Dexron II or Mercon".

 

 

Rob Spiegel
User Rank
Blogger
Re: Design flaws and rusted motor mounts.
Rob Spiegel   2/24/2012 10:28:37 AM
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Good points, Myronb. There are a whole host of problems that plague a car when it outlives its expected lifetime. While planned obsolescence may have been real during the mid 20th Century, it's understandable that car makers didn't expect their products to still be on the road decades later. But indeed, that certainly happened with the T-Bird and Mustang.

MYRONB
User Rank
Gold
Re: Design flaws and rusted motor mounts.
MYRONB   2/23/2012 9:47:44 PM
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It's both astonishing and sad that important automotive support structures such as body, frame, and engine mounts should be failure-prone in such numbers.   Because  product releases are so cost- and time-driven, manufacturers will start fishing before the bait was cut.  Whatever the reason, to the customer experiencing failures it appears  to be another example of "planned obsolescence," that is, the owner will have bought a new car before the failures become daily occurrences.  I learned the hard way that motor mount failures can result from failure of the bonding between the rubber vibration isolation biscuit found between the engine mounting bracket and the frame mounting bracket.  I had such an experience that now seems humorous, but which nearly resulted in the engine falling out of my van. You might be interested in the details of that calamity which was shown in a Design News article, http://www.designnews.com/author.asp?section_id=1386&doc_id=223529.

Regards,

Myron boyajian

nyeng
User Rank
Gold
Re: FMEA important design step
nyeng   2/23/2012 3:23:46 PM
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I worked for a large Tier I auto supplier working on driveline components.  I won't mention the company name since I will mention they screwed me out of my severance.  At any rate, DFMEA's were a joke.  The DFMEA was just another check box in the development plan and usually considered of low importance compared to getting the testing on the latest LCC sourced parts completed.  Thus the DFMEA was usually done last in the design process by whoever drew the short straw (DFMEA's were considered boring by most of us, and, because they were done AFTER design, rather pointless).  You usually took a DFMEA for a similar product or the previous version of the product, made some tweaks here and there, updated as much you could stand or had time for, got some signatures, filed it away in a book and on the server, and checked the box on the gantt chart.  The product got validated and put into production on time, you the lowly engineer got to keep your job (for now), project managers got gold stars, executives got bonuses, and the product wasn't as good as it could have been.  Pardon my cynicism, but that was the process as I saw it.

Rob Spiegel
User Rank
Blogger
Re: Rust on cars
Rob Spiegel   2/13/2012 12:11:11 PM
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I understand about rust, Rick, having grown up on the salty winter roads of Michigan. When I moved to New Mexico -- with absolutely no rust -- I met a guy who made his living by purchasing old cars (1950s, early 1960s) in pristine condition and driving them to Michigan where he sold them to collectors who couldn't find classics like the '55 Checy in perfect condition.

thechas
User Rank
Iron
Re: FMEA important design step
thechas   2/12/2012 3:25:19 PM
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A couple of general notes here.

First, the automakers have or at least had a time limit on all recalls that were not emissions or major safety recalls. If you purchased and registered a car after the notification period had expired, the automaker was under no obligation to send you a recall notice.

Dealers might only check the recall status if the work being performed involved the same area of the car as the recall.

Now with the fully computerized systems you have a much greater chance of being informed of every recall related to your car.

Second, while some chemicals can hasten rubber failure, I believe you will find that nearly every rubber motor mount will fail over time. The rubber dries out and just plain rots.

Interestingly, my 87 and 94 Taurus'es that I owned past 300,000 miles each were never recalled for subframe mounts. I did have to have 2 of the engine mounts changed out on my 87 though.

We owned an 86 Buick where the subframe itself rusted out. I went to jack it up to check the front brakes one day and we had a loud snap with a large cloud of rust around the jack. Inspecting the subframe at the other mounts, I decided it was not safe to drive the car. The only good repair option there would have been to replace the entire subframe. Got to love road salt.

Chas

KGround
User Rank
Iron
Re: FMEA important design step
KGround   2/10/2012 4:43:36 PM
NO RATINGS
Good thing he didn't hit a hard bump while going around a turn at 60 the day before innit ?

 

RICKZ28
User Rank
Platinum
Rust on cars
RICKZ28   2/10/2012 4:43:33 PM
NO RATINGS
1 saves
I lived in Maryland during the early 1980's.  All cars tended to have rust problems after a few years, due to the salt used on the winter roads.  The Honda cars seem to be the worst, frequently with rust through the body side-panels.  My 1975 Chevrolet Monza had its fair share of rust around the rear wheel wells.

I now live in Southern California, enjoy the wonderful weather.  My 13-year old 1998 Chevrolet Camaro Z28 looks just about brand new underneath...not one spec of rust.  It's rare to see rust on any car in SoCal, even close to the Pacific (salty air). 

David12345
User Rank
Platinum
Re: Another engine mount nightmare
David12345   2/7/2012 2:13:34 PM
NO RATINGS
Streetrodder,

From what I read about the 1971 National Highway Traffic Safety Administration (NHTSA) report to GM, the drivers side cable you mentioned may have been a dealer installed recall fix to the 1969 Chevrolet V8 engine mount prior to the "Safety Mounts" from the factory with interlocking steel plates starting around 1972.

Another example: The rear mount on the flat 6 Corvairs had interlocking steel backup structure from the start.  When these rubber parts failed the T steel would drop onto the sides of the steel channel slot.  This would then transmit much more engine and road vibration to the passengers until replaced, but without the steel backup the engine would have fallen onto the road.  To check, we would lay a straight edge across the rear mount. It should rest on the center steel T without touching the mount side rails.  If it touches the side rails the rubber had failed and the center T has dropped. I didn't use this information much because my last Corvair had a 327 cid SB Chevy V8 in a mid-engine configuration, but this was relevant for several friends with Corvair engines, (e.g. - street Corvair with modified 60 over 172 cid, big valve heads, big turbo and water injection putting-out 250+ hp, and the most radical one was a drag-track VW bug "Snoopy" with a Corvair engine  custom twin-turbo putting-out over 600 dyno-horsepower at 12,000 rpm and around 30 psi boost for short time periods between blowing it or the transmission up).

Ann R. Thryft
User Rank
Blogger
Re: Another engine mount nightmare
Ann R. Thryft   2/7/2012 12:31:56 PM
NO RATINGS

The fluid that destroyed my engine mount gaskets was transmission oil, so that fits. I made sure my new mechanic fixed the hose leaks that had caused the problem, and also checked all other hoses and gaskets. I've been pretty proactive about doing so on all my cars since then.


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