Changing Auto-transmission fluid

Is this a difficult procedure? Should I pay the 99 bucks at Jiffy Lube to do it, or is it something that I can do on my own? I have a 99 S-10 and
a father that is very good with cars....just looking for some opinions. Thanks.
DK
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Dave King wrote:

I can tell you about a lesson I learned the hard way...
I had a Cadilac Fleetwood several years ago that I took to a Jiffy Lube. They suggested that I have the transmission fluid completely replaced. Since I had bought the car used (at a dealer auction) and had no idea of the service history, and it did have over 100,000 miles, I figured it was probably a good idea.
Within a month, the transmission crapped out, slowly but surely. Had to buy a used one to replace it. My father, who is a used car dealer (and former new car dealer) said his mechanic said you should NEVER replace transmission fluid after a vehicle reaches over 100,000 miles. I forget the reason he cited exactly, but it had to do with it causing more flakes of metal to come loose and screw up the transmission. I am curious as to the opinion/experience on this of others.
--
Fris "Transmisius Interruptis" bee®, MCNGP #13

Certaholics
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the
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OK, thanks for the info....however, my 99 S-10 only has 38,000 miles on it. The technician at Jiffy Lube showed me the color of the auto-transmission fluid in my truck (light brown) compared to the color of new fluid (pink/bright red). He recommended that it be changed. Anyone else have helping ideas?
DK
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Just change the filter.
CJ

former
he
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There are 2 methods of changing tranny fluid. First is a "flush" method. This is probably what jiffy lube uses. They attach a machine to the tranny cooler lines and remove the old fluid and put in the new fluid. This changes all the fluid but does not change the filter. Most knowledgeable people in these groups don't reccomend this method. There are some horror stories about the tranny failing after doing this. I doubt if its very common, though, since lots of shops and dealers use it. The second method is the one I use. Its not that hard but you gotta have some mechanical ability. My 99 Z71 has a drain plug in the tranny. If yours does, it makes it easier to drain the old fluid. Then remove the the pan. All the fluid hasn't drained out of it so be careful and don't dump it all over. The filter doesn't even have a screw - it just pushes up in there. When you take the old one out, the O-ring might not come with it, so don't score the aluminum trying to get the old O-ring out. The new filter just pushes up in there and then put the pan back on. Some cautions - - look before you leap. My pan wouldn't come off without dropping the exhaust. You might have to remove the shift linkage to get to the pan bolts. The new gasket is cork. I used indian head gasket sealer, then ran some small wire through the bolt holes to hold the gasket in place. Start the bolts, pulling the wire out one at a time. Use a tightening sequence! If you don't understand torque values and steel bolts in aluminum holes, use a torque wrench. Get one of those cheap books at the parts store. Mine is a Haynes and it sucks but it provides basic stuff if you already have some knowledge. Clean the pan and mating surface. Read this: Clean the pan and mating surface. If the pan leaks, you can pretty much start over. Get it right the first time. P.S. In my opinion, jiffylube guys are NOT technicians. They have no understanding of transmissions. If you're still undecided, stop in a real tranny shop and relate the story to a mechanic that works on transmissions and get his thoughts on it. Just my .02 - - (and not even worth that!) .

former
he
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I think the idea of flushing the transmission is a bad thing for the reasons stated in a previous post.
I do know for a fact that the color of the fluid doesn't mean a thing. The odor it gives off will tell you more. Should smell, well...., oily, but not any trace of burned, as in burnt toast kind of a thing. If you changed fluids based on the color, you would have to change your engine oil every time you drove it :-) Look at the dipstick, and then look at the appearance of unused oil, and then go tell the Jiffy Lube guy to stop spreading manure around the shop <g>
It was mentioned to drop the pan, and if you have a drain plug in it, that would be easy. I have, in the past, siphoned the fluid out of the trans through the filler tube. There are hoses and adapters to get you there. This doesn't get all the fluid, the amount depends on the transmission, but I think it is a pretty safe method to getting some of the fluid out, and replacing it with cleaner oil, without much risk of messing up a working transmission.
I would avoid ever opening a working transmission. Dirt, other particles, dislogded o-rings, or check balls will ruin your day, and your wallet :-)
Just IMO,
John
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On Thu, 04 Mar 2004 14:50:21 -0700, snipped-for-privacy@aros.net wrote:

there are two basic types of "flushing" machines, the "backflush" type which has the rep of killing trannies and the newer type (trans tech is one brand) which simply allows the trans pump to pump out the old fluid while it infuses new fluid via the cooler lines. these machines are what most dealers and shops use. they can very precisely match the flow rate and pressure of the trans pump.

ATF isn't engine oil..... color is very important, if it's not red it's toast.
The

it should smell like ATF.

again, engine oil isn't atf, if it smells burnt at all it needs to be replaced pronto.

dropping the pan and changing filters changes between 1/3 and 1/2 of the fluid. if you keep a decent filter schedule (15k for non severe use) it'll keep the additive package fresh in the ATF.

if you don't drop the pan and change the filter, you're missing half the ball game. you won't have any dislodged O rings or checkballs by simply changing the filter... that would require removing the valve body.
-Bret
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Sorry to disagree, but one cannot judge the condition of ATF by looking at the color. That is not the way it is done.
However, I am wrong in that I seem to have mistaken the thread for one dealing with what to do with an older transmission that has not been serviced, and is getting up in the mileage. I thought the original poster was asking about the wisdom of using jiffy lube on an older transmission, and had mentioned that the 'tech' told him his fluid was bad because it was dirty looking, which is a total pack of lies.

Well, yea, I pretty much said that. Thanks for verifying my statement.

Golly, that is exactly what I said. If it smells burned, its hosed. You said you change it based on the color, and now you change it based on the odor. Only one of those is a valid method, and it ain't the appearance one. The color is not the way to determine if the fluid is still good or not. If you go by color, you will be spending a lot of money on ATF over the years.

Like I said, I was mistakenly of the impression we were discussing the average transmission with tons of miles that has never been serviced. There are very few of those around. Obviously, the way one would deal with a new trans involves all the required maintenance and changes of fluid and filter.
If I had a transmission with high miles, like 120K, on it that was functioning properly, but had not been serviced, I would not ever drop the pan, nor would I let Jiffy Lube or any other shop of horrors do a flush out job on it. I know I am the only one here who thinks that way, but I reserve the right to use years of experience to make my choices and to voice my opinion.
Usenet. What a joke.......
Thanks,
John
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I have a friend that was in the tranny business all his life with his father. he is now retired but tinkers in a backyard shop. When we changed the filter and fluid on the wifes Toyota and my GMC truck we dropped the pan, cleaned it well, replaced the filter, reinstalled pan and gasket. Filed up the tranny, and then broke open the dishcharege side of the tranny cooler lines from the radiator back to the tranny, cranked the engine up placed the end of thre hose in a can and when the fluid started to spit and putter, shut it off imediately, topped off the tranny again, and repeated the enigne run until spit and sputtering of fluid started again, and repeated this until the fluid came out the color of the fresh fluid. That was over 30,000 miles ago on my truck, so I don;t think it hurt anything. I plan on doing it again this weekend at my own shop now that I seen how it was done. Visit my website: http://www.frugalmachinist.com Opinions expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.
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Hey doc, you mean you don;t use those infglatable filters they sell now. They install like breast implants, that only need a little hole to get them in. NOt like the old ones where you got cut all to hell and back. No need to dropa pan anymore. Just shove em down the dipstick tube. Slickest thing I have seen a long time. And as you already said, there is always Jiffy lube, the masters of the car care world! Visit my website: http://www.frugalmachinist.com Opinions expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.
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the
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transmission
come
Your fathers mechanic gave you the biggest load of BULLSHIT I've ever heard. When fluid is old and expired it loses it's ability to lubricate, hence is useless. Leaving it in just exacerbates the problem and AT damage will ensue. Replacing old ATF with new restores the lubrication and protects the AT internals. Leaving old stuff in is the dumbest thing one can do. Looks like pop needs a new mechanic. This is true on any vehicle, regardless of mileage.
Your AT crapped out on the Caddy because Jiffy Lube didn't do the job correctly (can they do anything right?>.
Doc

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I've had both a flush and filter change done to my last 5 vehicles, each around 30K/mi, with no problems ... and I will continue doing same around each 30K/mi ... I definitely recommend both being done periodically.
Dave King wrote:

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