JasonA Posted July 14, 2005 Report Share Posted July 14, 2005 We're having a discussion on a minivan forum about changing old transmission fluid. What is the concensus here? I remember Guru saying on the old board that you can't really do damage to transmission simply by changing OLD fluid for new, but these folks see it differently. Comments? BTW, the first post is from me. The rest are from other users... Michael, thanks for bringing that up. I asked the GM powertrain engineer who frequents the Cadillac board I follow and he said that's an old wive's tail. He said that in all the R&D he's done, there's nothing to indicate that waiting too long to change fluid will ever hurt the transmission...not in a modern transmission with modern seals. He said that anytime you put fresh fluid in it, you'll help it rather than hurting it. I'll try to find the post for everyone's benefit. I did think of that way back when...but according to him it's not really valid. __________________ This will start a big debate I can see it coming LOL. I have been driving for 36 years plus and have had too many cars to remember and have only had two transmissions fail to date. Both were my fault. Hot rodding when I was younger. Yes I work in a dealership and tell people to follow the book on getting their car serviced. But I never service my transmission fluid if it is not discolored or smells bad. I have bought several high mile vehicles and I have learned to leave well enough alone. More than once I have had friends that service a high mile trans and in a mater of weeks they have total failure of the transmission. I also have followed the unwritten rule of if it looks good and smells ok to leave it alone. Most of the new cars have the metal strainer type filter instead of the cloth filter and I know this is part of the longer change time now on the newer cars . This is not to say that you do not need to adjust the bands ect on some of the transmissions that require this service. If I did change the fluid on a high mile vehicle I would not use the power flusher system . I would drop the pan change the filter and gasket make any adjustments called for and top off the system 4qts or what ever it takes in new fluid to bring the level up to normal. The new fluid in a high mile trans can dislodge old seals and cause clogged up control valves or external leaks. I did not know that Pat Goss had talked about this, but he usually tells it straight. Remember this is just what I do and may not be right for everyone. Also I do not pull a trailer and also install extra transmission coolers if the vehicle does not have one. __________________ First, I agree that going to another vehicle web site can be enlightining. Great info from the Cadillac site about the Chrysler trannies. NOW: I am not going to get into it again, however this is NOT AN OLD WIVES TALE. I have seen many transmissions that the owner waited over 100,000 miles to change the fluid and when they did, they had major problems. IF I change someones fluid that has not been change in over 75,000 miles , I make them sign a waiver stating that they may have problems BECAUSE of the change and that I told them about it. MOST shops in my area do that. My neighbor KNEW BETTER and within 2 weeks of changing the fluid in his truck, the tranny went out. He had over 125,000 miles and NO PROBLEMS with his tranny, he just wanted to change the fluid. He did not tow with it or even haul anything in it. You know, the typical urban truck owner. If you wait too long to change your fluid, then don't change it UNLESS you are having problems with your transmission. Then , it does not matter because the transmission is already starting to go. Do as you wish, just letting you know. __________________ I agree not to change the fluid on a high mile vehicle like I stated in my post yesterday. I was sure that I would get a lot of flack about that post. I have known of too many cases that someone changed the fluid and in a few weeks the trans went south. We at the dealer also tell customers to change at your own risk. We use to tell people to change every 30,000 miles unless they pulled a trailer. and then at about 15,000 miles or once a year. Now the books say 100,000 miles or not required at all. No way would I change my fluid on a 100,000 mile vehicle unless I was ready to have the transmission rebuilt. I was glad to see someone like Pat Goss talk about this on TV. A lot of people will here what he said and not get into trouble with a trans fluid change. If the new transmissions did not use electronic controls they would last longer. The old Ford 4AOD was a mechanical 4 speed automatic and usually lasted a long time without trouble. The electronics in a trans just can't take the heat and fail. If we had a good mechanical transmission with the improved fluids of today the trans would last forever. __________________ > Another thing you have to remember with the new electronic transmissions is that it is full of solenoids. A solenoid is a - magnet - and it attracts all the "junk" in the fluid, putting it in the middle of more possibillities of failure. However, we all know that the 'new and improved' transmissions with all the electronics are here to stay. Therefore we must learn to adapt. Any/every time a vehicle salesman tells me about the "100,000 miles between servicing" I tell him what a load of marketing crap that is and how it just alienates the customer when he finds out the real truth AFTER he buys the vehicle. I am talking of ALL MANUFACTURERS and the way the salespersons present it. __________________ Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
JimD Posted July 14, 2005 Report Share Posted July 14, 2005 When a transmission fails following a fluid change, there has to be a mechanical reason 'other' than new fluid. It is not automatic (pun intended) that the tranny will fail in two weeks or some number of miles following a carefully done fluid change. The original factory fill was pumped out of my '98 15 months and 16,000 miles ago. Did not expect and have not had any tranny problems before or since. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
Scotty Posted July 14, 2005 Report Share Posted July 14, 2005 This just confirms my opinion that transmissions for most people are scary, voodoo science and they fear them greatly. I do not see how dropping the pan and changing the fluid could hurt anything. I do think that if the filter is not installed correctly THAT can be the root cause of a failure after the fluid is changed. (and if you have ever changed a filter on a 91 Seville you know how hard it can be to remove the seal and to get the filter back into place in the seal). Failures can be caused by; utilizing the wrong fluid, flushing, overfilling it, underfilling it, and installing a pan and having leaks that allow the fluid to run low. I think there are a lot of other factors that can contribute to tranny failures after the fluid is changes OTHER than the fluid change itself. Mike Link to comment Share on other sites More sharing options...
Oldgamer Posted July 14, 2005 Report Share Posted July 14, 2005 This just confirms my opinion that transmissions for most people are scary, voodoo science and they fear them greatly. I do not see how dropping the pan and changing the fluid could hurt anything. I do think that if the filter is not installed correctly THAT can be the root cause of a failure after the fluid is changed. (and if you have ever changed a filter on a 91 Seville you know how hard it can be to remove the seal and to get the filter back into place in the seal). Failures can be caused by; utilizing the wrong fluid, flushing, overfilling it, underfilling it, and installing a pan and having leaks that allow the fluid to run low. I think there are a lot of other factors that can contribute to tranny failures after the fluid is changes OTHER than the fluid change itself. Mike Exactly, Scotty It scares me to death Yesterday late I could not sleep and I took the manual and try to understand how transmision works. And it is complicated. After couple pages I realised that i'm sleeping... I agree with you that most problems after fluid change happened because of sloppy work or because transmission was on a way down. New oil itself can't be a problem. Let be realistic: do mechanics always follow the manuals instruction when they unscrew/screw bolts? I don't know for sure, but I think that they are don't. And this is a simpliest part. I scare even to drop the pan. Link to comment Share on other sites More sharing options...
adallak Posted July 14, 2005 Report Share Posted July 14, 2005 I changed the ATF and filter at 100.000 and 144.000. No problems. Just take your tme, clean th epan, use quality parts, gaskets, follow the torque specs and you'll be fine. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Scotty Posted July 14, 2005 Report Share Posted July 14, 2005 I changed the ATF and filter at 100.000 and 144.000. No problems. Just take your tme, clean th epan, use quality parts, gaskets, follow the torque specs and you'll be fine. Adallak, how did you find changing the filter seal on your 91? Mike Link to comment Share on other sites More sharing options...
CaddyChris Posted July 14, 2005 Report Share Posted July 14, 2005 Hey Guys, This is great that this topic is opened, I was reading the archives about changing tranny fluid. here is the thing. My car has 247k on it. Put a different engine in at 237k. I have no idea of the service record. I checked the tranny fluid the other day and it was not red. It was a brownish color and it smelled burnt. I know not to get a flush. Should I change the fluid? Correct me if I am wrong, I just have to drop the pan and than open up a drain bolt like changing the oil or is it much more involved? Also, what about the filter... is this more work? Thanks. Chris Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
adallak Posted July 14, 2005 Report Share Posted July 14, 2005 I changed the ATF and filter at 100.000 and 144.000. No problems. Just take your tme, clean th epan, use quality parts, gaskets, follow the torque specs and you'll be fine. Adallak, how did you find changing the filter seal on your 91? Mike Mike, the manual said to not change the seal if it is ok. It's exactlu what I did - put th enew filter on the old seal. The temptaiton to replace the old seal with new one was hard to refuse though. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
CaddyChris Posted July 14, 2005 Report Share Posted July 14, 2005 Hey, 1 more thing...I have heard this to...about trannys failing after changing the fluid. Someone told me it's because the old fluid has particles and such keeping everything together. They said that when you put new fluid in it lacks all the particles thus changing viscocity(sp) and than the tranny fails. I am not sure if I should change it or not. It smells burnt, looks brown and the tranny has been doing wierd stuff occasionally(it shifts fine but occasionally there will be an abrubt or awkard shift). ANy comments? Chris Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
adallak Posted July 14, 2005 Report Share Posted July 14, 2005 Hey,1 more thing...I have heard this to...about trannys failing after changing the fluid. Someone told me it's because the old fluid has particles and such keeping everything together. They said that when you put new fluid in it lacks all the particles thus changing viscocity(sp) and than the tranny fails. I am not sure if I should change it or not. It smells burnt, looks brown and the tranny has been doing wierd stuff occasionally(it shifts fine but occasionally there will be an abrubt or awkard shift). ANy comments? Chris "particles in the fluid"... I believe some mechanics can explain easily and popularly how a nuclear reactor works (must be some particles ) despite they do not have any idea about say, chain reaction. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
CaddyChris Posted July 14, 2005 Report Share Posted July 14, 2005 Hey,1 more thing...I have heard this to...about trannys failing after changing the fluid. Someone told me it's because the old fluid has particles and such keeping everything together. They said that when you put new fluid in it lacks all the particles thus changing viscocity(sp) and than the tranny fails. I am not sure if I should change it or not. It smells burnt, looks brown and the tranny has been doing wierd stuff occasionally(it shifts fine but occasionally there will be an abrubt or awkard shift). ANy comments? Chris "particles in the fluid"... I believe some mechanics can explain easily and popularly how a nuclear reactor works (must be some particles ) despite they do not have any idea about say, chain reaction. haha, I hear ya...so you think I should change it? Chris Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
adallak Posted July 14, 2005 Report Share Posted July 14, 2005 Hey,1 more thing...I have heard this to...about trannys failing after changing the fluid. Someone told me it's because the old fluid has particles and such keeping everything together. They said that when you put new fluid in it lacks all the particles thus changing viscocity(sp) and than the tranny fails. I am not sure if I should change it or not. It smells burnt, looks brown and the tranny has been doing wierd stuff occasionally(it shifts fine but occasionally there will be an abrubt or awkard shift). ANy comments? Chris "particles in the fluid"... I believe some mechanics can explain easily and popularly how a nuclear reactor works (must be some particles ) despite they do not have any idea about say, chain reaction. haha, I hear ya...so you think I should change it? Chris I would change and ASAP. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Scotty Posted July 14, 2005 Report Share Posted July 14, 2005 I changed the ATF and filter at 100.000 and 144.000. No problems. Just take your tme, clean th epan, use quality parts, gaskets, follow the torque specs and you'll be fine. Adallak, how did you find changing the filter seal on your 91? Mike Mike, the manual said to not change the seal if it is ok. It's exactlu what I did - put th enew filter on the old seal. The temptaiton to replace the old seal with new one was hard to refuse though. That's histerical! Don't get me started on the manual, they also say NOT to resurface the rotors, Adallak you know me a long time, and you KNOW that I pulled that seal out! And yes I can report that it was lots of fun...GETTING THE NEW ONE IN! But it finally went it. In my mind that they provide a new seal, it must be for a reason! So who am I to test their reasoning... I figured that the old one might be dryrotted and possibly heat formed to the OLD filter, and now the new filter may not 'sit' in the same groove and potentially suck air....and cause the tranny to whine...and cavitate I KNOW, I KNOW.....I think TOO much.. (but I sleep good too ) Link to comment Share on other sites More sharing options...
KHE Posted July 14, 2005 Report Share Posted July 14, 2005 Hey,1 more thing...I have heard this to...about trannys failing after changing the fluid. Someone told me it's because the old fluid has particles and such keeping everything together. They said that when you put new fluid in it lacks all the particles thus changing viscocity(sp) and than the tranny fails. I am not sure if I should change it or not. It smells burnt, looks brown and the tranny has been doing wierd stuff occasionally(it shifts fine but occasionally there will be an abrubt or awkard shift). ANy comments? Chris What would the particles be keeping together??? Drop the pan, change the fluid and refill. Use the OEM pan gasket for best results. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
KHE Posted July 14, 2005 Report Share Posted July 14, 2005 Hey Guys,This is great that this topic is opened, I was reading the archives about changing tranny fluid. here is the thing. My car has 247k on it. Put a different engine in at 237k. I have no idea of the service record. I checked the tranny fluid the other day and it was not red. It was a brownish color and it smelled burnt. I know not to get a flush. Should I change the fluid? Correct me if I am wrong, I just have to drop the pan and than open up a drain bolt like changing the oil or is it much more involved? Also, what about the filter... is this more work? Thanks. Chris Your STS has screens under the pan - just make sure they are not restricted. The filter is behind the side cover - you would need to drop the trans to change it. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
JIMDTS Posted July 14, 2005 Report Share Posted July 14, 2005 I like to change the trans fluid and filter at 50k. I know it can go longer but I would rather get it out before it gets funky. Most of these transmission places I would steer clear of and do the job yourself and if you can't do it take it to a dealer or friend you can trust to do the job. One time I was with a buddy of mine and he took his car to one of those cheap 29.95 specials that these trans shops offer and while we were waiting here comes the owner of the shop with his old filter showing it to him and it had one or two small particles of metal inside the filter which in my book at a 100k was good the guy is telling the guy your trans is going bad it needs a rebuild I told the guy just put a new filter in it and service it my buddy put another 100k trouble free miles on it. While we waiting sure enough the guy comes out with the same pitch to another customer and this customer bit and they got an overhaul job I wll do the fluid change on my cars when the time comes.. Good Luck Jim Link to comment Share on other sites More sharing options...
CaddyChris Posted July 14, 2005 Report Share Posted July 14, 2005 Thanks everyone, Most likely I'll change it this weekend. Chris Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
adallak Posted July 14, 2005 Report Share Posted July 14, 2005 I changed the ATF and filter at 100.000 and 144.000. No problems. Just take your tme, clean th epan, use quality parts, gaskets, follow the torque specs and you'll be fine. Adallak, how did you find changing the filter seal on your 91? Mike Mike, the manual said to not change the seal if it is ok. It's exactlu what I did - put th enew filter on the old seal. The temptaiton to replace the old seal with new one was hard to refuse though. That's histerical! Don't get me started on the manual, they also say NOT to resurface the rotors, Adallak you know me a long time, and you KNOW that I pulled that seal out! And yes I can report that it was lots of fun...GETTING THE NEW ONE IN! But it finally went it. In my mind that they provide a new seal, it must be for a reason! So who am I to test their reasoning... I figured that the old one might be dryrotted and possibly heat formed to the OLD filter, and now the new filter may not 'sit' in the same groove and potentially suck air....and cause the tranny to whine...and cavitate I KNOW, I KNOW.....I think TOO much.. (but I sleep good too ) Oh Mike, please, please do not remind me of tranny whine... It kills me when i do not know what is wrong with the car or myself! Just remmber these cars are supposed to serve us not us serving the cars (all the time ). The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Scotty Posted July 14, 2005 Report Share Posted July 14, 2005 I am a SLAVE to my car! (and I like it) Hey listen there are worse things to be addicted to, I don't gamble, drink or chase women (unless I am in my car) Link to comment Share on other sites More sharing options...
JasonA Posted July 14, 2005 Author Report Share Posted July 14, 2005 Did anyone happen to save Guru's old post from the old board. I know a few of you have kept "the bible" around. The old archives are down, and I'd really love to be able to get access to what he said...basically, I think he said that's not true in most cases, and it's just an urban myth...but I don't want to put words in his mouth. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
DFBonnett Posted July 14, 2005 Report Share Posted July 14, 2005 Changing Old Tranny Fluid? Rule #1 New fluid is the best fluid Rule #2 See rule #1 Take that to the bank. I used to hear all the crapola years ago about how changing fluid ruined the trans as it was "used to the old fluid", etc, etc, yadda, yadda, yadda. People would wait until there was an apparent driveability problem, then change the fluid. then blame the change when the tranny failed. Goat droppings. Link to comment Share on other sites More sharing options...
johnnydone Posted July 14, 2005 Report Share Posted July 14, 2005 the older train of thought in the older transmissions was that tranny fluid was a cleaner and after it is in the trans for a long period of time it loses its cleaning properties by changing fluid it cleans the trans and starts moving the metal particles through the trans hence failure Guru stated that this was not true in the northstar Link to comment Share on other sites More sharing options...
adallak Posted July 14, 2005 Report Share Posted July 14, 2005 I am a SLAVE to my car! (and I like it) Hey listen there are worse things to be addicted to, I don't gamble, drink or chase women (unless I am in my car) Are you telling to me that chasing Open MAP Sensore Circuit is more entertaining than chasing women? The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Scotty Posted July 14, 2005 Report Share Posted July 14, 2005 Ummm, YES! Link to comment Share on other sites More sharing options...
JIMDTS Posted July 14, 2005 Report Share Posted July 14, 2005 I would go with chasing women as long as you catch them is what counts but the chase is fun too Chasing an open map sensor would be the smart thing to do..trust me it's expensive to change wives..I don't want to go down that road again I have some women that chase me but when I think about a trade in on the wife I pass I'm sure my attorney would love to handle another divorce case..One can dream though Just the other day I had an offer fron this woman who is a real beauty I had to pass on it but in my younger days I would have jumped on it in a heart beat..I guees you get some smarts with age jim Link to comment Share on other sites More sharing options...
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