Many moons ago, I had an 78 Chevy heavy half pick up got it for next to nothing so I was changing all the fluids and filters and I changed the tranny fluid and filter. 3 weeks later the tranny died, sold the truck
Fast forward a few years. Had a Plymouth Voyager 100K + on the odometer. Thought it would be wise to change the tranny fluid and filter. 90 days later tranny died.
More fast forward. 3 years ago on my 99 Silverado 120K + on the odometer same deal, the tranny dies 5 days after.
Last weekend I noticed on the same Silverado 190 K on the odometer the tranny fluid looked just a fuzz dark.
Now the point of the tread. Do I change the fluid and filter? Is there something by changing the fluid and filter that would cause tranny failure? In all of the above one of the gears got stripped.
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07:51 AM
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jaskispyder Member
Posts: 21510 From: Northern MI Registered: Jun 2002
well, there are those who say "don't change the fluid after 100K". And I agree, unless your fluid is looking bad, but by then you probably have other problems. I know on my Aztek the fluid was fine, but the tranny was going anyway. Another thing to consider, did you use the correct tranny fluid?
J.
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07:56 AM
blackrams Member
Posts: 31842 From: Hattiesburg, MS, USA Registered: Feb 2003
Originally posted by ohioindy: Do I change the fluid and filter?
No. I am a believer in the "don't change it if it has never been changed after 100K" school. I have seen too many failures after that. And it seems that you have as well. Change the fluid, flush the system, but don't change the filter. I have seen that work. But everytime that I know of where someone has actually changed the filter itself after 100k when it has never been done before I have seen nothing but failure. I don't know of the reason....I have heard many. The one thing I know is that if it were my vehicle I would not change the filter. Period.
But that is just my opnion and experience. I am sure that there are others out there who will call me an a--clown because of it.
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08:16 AM
82-T/A [At Work] Member
Posts: 22772 From: Florida USA Registered: Aug 2002
No, it's not you, but it's also not co-incidence...
The PROBLEM is... that, if a transmission isn't serviced regularly... IE: every 30-60k miles, then what happens is the old transmission fluid begins to deteriorate. The contaminents in the fluid begin to stick to everything, including seals, and discs, etc. Now, what happens when you put new fluid in, is that the newer fluid will actually clean the transmission. Newer fluid for obvious reasons has more of it's caustic properties than older oil does. So... all that gunk that's now "protecting" the old hardened seals, will get flushed out. And now suddenly, your seals fail... and the transmission fails, and things like preventing you from being able to shift into gear, or upshifting, etc... that all starts to become a problem.
In cases like this, it's NEVER a mechanical problem as changing the fluid simply cannot cause mechanical failure unless you're simply not using ENOUGH fluid. However, the damage that is caused (as explained) is usually with regards to the seals, etc. This usually requires a rebuild of the valve body... which in most cars requires you to remove the transmission. :/
One thing you CAN do, however, is to change out the fluid little by little.
For example, take a quart out (using a hand pump with a tube stuck down into the dipstick tube). And replace the fluid with new fluid, 1 quart at a time, every month, until your fluid is genuinely clear, and then you can swap out the filter too. The thing is... as I explained, the gunk from the old oil creates a seal around the old seals. This is good and bad, but bad in that it prevents the seals from getting fresh oil for LONG periods of time. The fresh oil actually keeps seals "swelled" and prevents leaks, but when they become saturated in old caked on deposits, it can cause them to deteriorate, get overheated, and crack.
By introducing a little bit of new fluid at a time, you stand a better chance of allowing those seals to slowly soak back up that new oil and swell up again, while at the same time, cleaning the contaminantes. It's not a sure fire way, but it beats doing it all at once and blowing your transmission.
I suggest doing it every 35k miles. I've done that on the Th-125 in my Fiero and I used to do neutral drops ALL the time when I first got the car (before I knew it was bad). It's still a totally solid transmission 13 years later (from my neutral drop phase).
My 99 Silverado has 248,XXX miles on it. I have changed the fluid and filter 5 or 6 times since I bought the truck new. The last 3 or 4 changes have been after the 100,000 mile mark and I have never had a problem (except the time I accidentally disconnected the 2-3 shift servo). I even tow with it (6000 lbs average) once or twice a month.
Now I'm scared to touch it.
------------------ 1986 SE 350 V8
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10:16 AM
Pyrthian Member
Posts: 29569 From: Detroit, MI Registered: Jul 2002
Originally posted by tesmith66: My 99 Silverado has 248,XXX miles on it. I have changed the fluid and filter 5 or 6 times since I bought the truck new. The last 3 or 4 changes have been after the 100,000 mile mark and I have never had a problem (except the time I accidentally disconnected the 2-3 shift servo). I even tow with it (6000 lbs average) once or twice a month.
Now I'm scared to touch it.
dont be - you've done the regular changes - so the tranny is happy. keep doing what you are doing. it is the RIGHT way to maintain a trans.
OK here's my explanation, the clutch friction material is floating in the fluid giving the worn clutches grip. Take out the old fluid and presto the clutches slip.
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12:42 PM
fierobear Member
Posts: 27079 From: Safe in the Carolinas Registered: Aug 2000
My 99 Silverado has 248,XXX miles on it. I have changed the fluid and filter 5 or 6 times since I bought the truck new. The last 3 or 4 changes have been after the 100,000 mile mark and I have never had a problem (except the time I accidentally disconnected the 2-3 shift servo). I even tow with it (6000 lbs average) once or twice a month.
Now I'm scared to touch it.
No, no... don't be confused. The problem is if it's changed AFTER 100k miles where by NO PREVIOUS SERVICE HAD BEEN PERFORMED.
If you changed your fluid AT LEAST ONCE before 100,000 miles, then you're TOTALLY ok...
Really, transmission fluid NEEDS to be changed every 65k miles.
The first thing I did when I bought my truck was to put an external filter and cooler on it. After driving for a couple of months, I figured that all of the particles should have been caught by the filter so I flushed the whole system and put in new fluid. I bought the truck with 120k on it and no idea if the previous owner ever replaced the fluid.
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01:37 PM
rogergarrison Member
Posts: 49601 From: A Western Caribbean Island/ Columbus, Ohio Registered: Apr 99
Rule is if tranny has never been routinely serviced per maint schedule, DONT EVER mess with it. Anyone that did change fluid / filter lost that transmission within a month or so. The grit and crap in the old fluid is the only thing keeping it still reasonably working. Take that out and its toast really quick....as you already just found out.
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04:18 PM
frontal lobe Member
Posts: 9042 From: brookfield,wisconsin Registered: Dec 1999
So if you are changing the transmission fluid at regular intervals from the beginning of having the car new or slightly used, is there any purpose in this transmission FLUSHING? Why is that necessary? Why can't you just change the fluid and filter?
What is the difference in price?
Thanks. Interesting discussion.
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04:26 PM
Patrick Member
Posts: 36413 From: Vancouver, British Columbia, Canada Registered: Apr 99
That's how we make our money. To drop the pan and change the filter I use about 3 to 4 Qt. To flush the system I use 10 to 12 Qt. The Torque converter holds about 6 qt and the lines all have dirty fluid so why not get all of it out.
