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Transmission Chevy truck- smoke everywhere!


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Txhorsmn
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Dec 19, 2015, 5:28 PM

Post #1 of 25 (1991 views)
Transmission Chevy truck- smoke everywhere! Sign In

Driving my 1996 Chevy 1/2 ton pick up (4L80E & 5.7 / 350, mild street cam) on freeway pulling empty 16 foot tandem axle trailer. I see a small amount of white smoke on passenger side as I watch my mirrors. On the free way no exit, smoke clears. Try to nurse it to an exit. Then within a mile or so... Smoke everywhere, white smoke a huge amount, both sides of truck coming from underneath, and it seems as if the torque converter quit being engaged. So coast over to shoulder, then get out, fluid everywhere under truck. Smoke appears to be caused by fluid hitting exhaust pipes. Reddish, appears to be tranny fluid. Check oil, good level, motor runs fine. Check tranny fluid level is good, maybe a bit high but who knows - not exactly the correct way to check it.... Puzzled where did fluid covering entire undercarriage come from. On a whim check radiator. Empty. Hmmm. Is it possible that the tranny cooler is integral to radiator an barrier wall broke causing coolant in tranny fluid. Would this cause high pressure to blow tranny line? After towing, on level ground at house, motor runs fine, it will back up a little, barely move forward. Perhaps it is due to low fluid or viscosity of contaminated fluid. I dunno. Where do I start, any help appreciated.


(This post was edited by Txhorsmn on Dec 19, 2015, 5:55 PM)


gsferraro
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Dec 19, 2015, 7:40 PM

Post #2 of 25 (1962 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In

Hello,
Inside the radiator is a heat exchanger to keep the trans fluid cool, if the coolant and trans fluid mix,the fluid in the trans will look like a strawberry milkshake. If you pull the stick out of the trans is it full? look at both sides of the stick, you may have to put this on a rack to see exactly where the leak is coming from


Txhorsmn
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Dec 19, 2015, 7:52 PM

Post #3 of 25 (1961 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In

Thank you for your reply. No I don't have a milkshake, and with it in neutral, engine hot, I appear to still have adequate tranny fluid. Yet, the entire undercarriage is coated in reddish brown fluid. This would not have shocked me if I had low fluid on the tranny stick, but I don't. I just checked all fluid levels before hooking up the trailer, and all was good. I am almost positive that the fluid which is on the undercarriage and created the smoke is tranny fluid, perhaps it was over filled as I just bought the truck and though I doubt it I might not be the best at checking tranny fluid levels. I did look at both sides of the stick, bother the same. Obviously I have to find what tranny line ruptured and replace, but I am concerned there might be more to it, hence the post. I really appreciate your time. If I end up at a tranny shop I want to be well informed as my luck at those places is less than stellar, and I am 1000 miles from home an my regular trusted tranny guy. Any other thoughts? Thanks again.


Txhorsmn
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Dec 19, 2015, 7:59 PM

Post #4 of 25 (1959 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In

Sorry but ... I can rebuild a motor, but I am no tranny guy. To find my leak is it sufficient to have the truck running, and get underneath to see? I am not familiar with how pressure builds up, is it related to RPM or? Thanks again


Txhorsmn
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Dec 19, 2015, 8:45 PM

Post #5 of 25 (1952 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In

I realize this is not solvable over the Internet but in order to proceed I have several questions. As the Tranny expert here I would appreciate your input Gus. My next few days are going to be involved in this, trying to get home for Christmas with the truck. So here goes-
What effects or controls the pressure in tranny lines?
The truck is old with 200k miles, based on this forum and my own experience power flushing is a bad idea, but... If my fluid is contaminated with coolant it seems that is required. I don't suppose draining and new filter is adequate. Would you concur?
It seems to me that again based on previous experience, the loss of fluid has made the volume or level of fluid to be too low for the torque converter to function properly. Is it possible my torque converter is bad? Is that likely?
Is it possible/ likely anything internal to the transmission was damaged in this event?
Is there any way to verify the if tranny cooler in the radiator has enjoined itself with the coolant cavity? Can you confirm this tranny cooler in a 1996 Chevy truck is integral to the radiator? As you know replacing the radiator is quite a chore.
Finally, assuming I find the leaking component, and replace it, what process should I go thru to refill it, get functional. How do I verify the radiator is OK. THANKS FOR YOUR TIME


Hammer Time
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Dec 20, 2015, 6:33 AM

Post #6 of 25 (1929 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In

I don't know how much help you'll get if you keep calling him Gus. His name is Gary.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Discretesignals
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Dec 20, 2015, 7:16 AM

Post #7 of 25 (1917 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In

I'd say the most important part of trying to figure out what is going on is to find out where the leak is coming from first and to also figure out why the coolant level was low in the radiator. Worry about the million other questions later. You may need to clean everything up under the vehicle to see where the leak is coming from.

I'd fill the radiator back up and disconnect the lower transmission cooler line from the radiator. Then pressure test the system using a coolant system pressure tester to see if there are any leaks. If the transmission cooler is leaking you may see coolant come out the port where the line was attached. Majority of the time if the cooler was leaking, the engine coolant would be contaminated (milkshaked) because with the engine running there is more pressure in the trans cooler than the coolant system. If coolant had contaminated the fluid in the transmission, the transmission is done and needs to be replaced or completely overhauled.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Dec 20, 2015, 7:29 AM)


kev2
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Dec 20, 2015, 7:33 AM

Post #8 of 25 (1907 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In

Some quick thoughts-
Is this 4wd?
Right now - if you select D will it move?
Is the CEL on? what codes?
Your claim that trans fluid color is NOT as obvious a suspect as gary's pink reference THEN
COULD the engine cooling system have lost all fluid, that white smoke L/S, next eng overheated, THEN the trans overheated and 'vented' causing the major smoke issue?
Yes you could rig up a way to test trans cooler in radiator... 1) remove trans coolant lines use a hose and clamps to route one trans line to the other bypassing radiator, then pressure test radiator, 2) a BRIEF engine run in P/N would also work .... Observe if coolant leaves those open trans line holes in radiator...


gsferraro
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Dec 20, 2015, 7:44 AM

Post #9 of 25 (1905 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In

I will answer your questions, then i have a few.
Pressure is created by the pump in the transmission, but it is regulated by a valve called a pressure regualtor valve also located in the pump. It also works with a solenoid called an EPC(eletronic pressure control) this solenoid turns on and off via the computer, this also regulates pressure inside the trans, as the engine works harder the computer will raise line pressure via the epc solenoid. At an idle your pressure should be around 60 psi, on the highway doing 65mph your pressure may be 130psi. If you want to see if trans fluid entered the radiator just take the cap off and look if its milky then the fluid is in there. All radiators have the heat exchanger inside them to keep the fluid cool(when i say cool ,about 200 degrees).
The trans gets refilled by adding through the filler tube, but check it first to see whats in there you dont want to overfill the unit. If water got into the trans draining and filling wont really help, once the gets in there the trans is done.

To answer more of your questions, i have to ask a few, does the truck move? Is the transmission full, if it is what is the condition of the fluid, what does it smell like? was the truck scanned yet for codes? It is possible if the trans got hot the fluid came out the vent.
Your asking about the converter it is possible its bad, please answer my questions so i have a better idea about the transmission


Txhorsmn
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Dec 20, 2015, 11:35 AM

Post #10 of 25 (1893 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In

Wow, you guys have blown my simple mind. But... For the record I typed GS and the iPad determined to spell check and make it Gus. The truck is NOT 4 WD. Yes as I previously stated it moves, very little, backwards better than forward, as previously described. I actually feel comforted, as I don't appear to have a contaminated fluid in either the radiator or the trans. Meaning I don't see any milkshake anywhere. As to what it smells like, guess my snoot is not that discriminating, all smells like ... Used motor oil to me. I have not been to the shop to get codes, I am traveling and as my previous post indicate I am trying to get educated before I get there. Pre- Christmas weekend stranded on the road, no shop I could find would take me unless I bought into an 8 day wait. I am off to check out all the things everybody just taught me, I will report in tonight. Only one question this time, what I am hearing is... If the tranny fluid is contaminated, then the tranny is toast? So time to go buy a used tranny? Thanks for everyone's help. Tune in later, we will have more info.


Txhorsmn
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Dec 20, 2015, 11:42 AM

Post #11 of 25 (1892 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In

I also want to say this vent scenario is very interesting and will check the things you advised. Report tonight...


Txhorsmn
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Dec 20, 2015, 11:51 AM

Post #12 of 25 (1889 views)
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The engine temp gauge never reached above 180, always below 200, just as a good 350 with a 180 thermostat should be...BTW. sorry to reply piecemeal, best I can do as I absorb info, an the site does not allow me to review all input when reply window is open


Txhorsmn
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Dec 20, 2015, 11:55 AM

Post #13 of 25 (1888 views)
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It is huge to know the Tranny pressure exceeds the coolant pressure. That helps enormously. I did not know. That one answer, means a lot. It is also huge to know that if fluid got contaminated, then go buy a used tranny, thanks so much. More coming going to lay under a truck.. LOL


gsferraro
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Dec 20, 2015, 11:56 AM

Post #14 of 25 (1888 views)
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If the trans is full and it barely moves in either direction, very posible the torque converter is no good because there is nothing common thats applied in foward and reverse, let me know what you find out.


Txhorsmn
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Dec 20, 2015, 11:59 AM

Post #15 of 25 (1887 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In

It on
Y moves a bit each way, little better in reverse vs. forward. How do I test torque converter? Assuming I fix leak...


Hammer Time
Ultimate Carjunky / Moderator
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Dec 20, 2015, 12:14 PM

Post #16 of 25 (1884 views)
Re: Transmission Chevy truck- smoke everywhere! Sign In


Quote
The engine temp gauge never reached above 180, always below 200, just as a good 350 with a 180 thermostat should be..


No, that's not how that engine should run. That engine requires a 195 degree stat. Numerous computer controls are effected by that. It may not even go into closed loop.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Txhorsmn
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Dec 20, 2015, 12:18 PM

Post #17 of 25 (1878 views)
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Hammer based on your response to others and your responses to me, thank you very much but I don't need your help. I have built dozens of 350's/ 5.7's . Some with thousands of dollars of performance parts from summit. So just move along. You seem to enjoy being critical of people, I am not interested in that input.


Tom Greenleaf
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Dec 20, 2015, 12:19 PM

Post #18 of 25 (1878 views)
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Quote from earlier post:">>No I don't have a milkshake, and with it in neutral, engine hot, I appear to still have adequate tranny fluid. Yet, the entire undercarriage is coated in reddish brown fluid.<<"
Sorry if covered already but unless totally blind this says you checked trans fluid in NEUTRAL - right? You check these in park warmed up and level. Long stick so check twice.
OK: It's doesn't mean damage hasn't happened but it would read higher level in Neutral but with the soaked underside with ATF said it was in range?
About can't be for real and if not contaminated they do get hot - empty trailer or not as some speed so if overfilled a reason to purge out excess Gary would know best what that and now running low on ATF would or could do better.
Also - You've or whoever messed with camshaft (why I don't know as Vortecs have tons of power to me) probably had either engine out or everything out in front to do that. Trans lines new condition if so don't like rubbing and are carefully separated and routed not to. If not it's a problem waiting to happen. With the load, engine torqueing more for longer, overfilled is a maybe IMO really blew out a lot of ATF. It also doesn't take much to make a mess but with above info we don't really know or I don't.
It doesn't solve the problem just a possible reason for a leak and reason it's been running with improper level.
It's a horrible week to have a problem like this if not really easy but if something like that mistake or problem with lines caused this it would do it to a perfect used one now too if you could pull that off fast enough. Just something to think about while you are probably pulling your hair out,


T



Hammer Time
Ultimate Carjunky / Moderator
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Dec 20, 2015, 12:23 PM

Post #19 of 25 (1871 views)
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Well, smart ass, unless you have reprogrammed that computer. It' looks for that temp and will prevent it from going into closed loop. Your back yard muscle cars are quite different from this computer controlled vehicle.

Now, choose your next words very carefully.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Txhorsmn
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Dec 20, 2015, 12:39 PM

Post #20 of 25 (1868 views)
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Tom, I am struggling to understand your post, probably too dumb. But yes I checked it twice hot in park, and in neutral. Since I am no tranny guy but am a Chevy guy an this is what I knew. Really no difference. I checked it on the side of the road which was not level then at the parking lot I towed it to, very level ground. Same results. This is a poor communication media, for this issue, but I value your input, so given this info, what are you telling me? Thanks for your time.


Tom Greenleaf
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Dec 20, 2015, 12:50 PM

Post #21 of 25 (1860 views)
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OK - Out of this after this. They only count checked in park as in "N" and really should be all different as torque converter is either spinning around fluid or not. Mopars historically you checked in "N." - Real Mopars.
So it was just two thoughts that could mess you up or be initial problem. With lines from trans to radiator and on to an aux cooler if equipped no joke, new lines if were needed rubbing make holes and a real mess - it's happened. Line should be bent exactly or original with all items that hold them in place. Some use just separator clips for longer spans.
It's just line but it can't rub anything is my real point with engine motion, vibrations and so on, that's all,


T



Txhorsmn
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Dec 20, 2015, 12:55 PM

Post #22 of 25 (1855 views)
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Tom, I have seen you on other sites and know you are very knowledgable. I do not understand why you reference Mopar when we are dealing with Chevy, but I value your input. What I am hearing is be sure line replacement is OEM. I will do that. Is there more you are saying that I am not hearing?


Txhorsmn
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Dec 20, 2015, 1:10 PM

Post #23 of 25 (1851 views)
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Ok, I am checking this when I crawl out from underneath the truck. I bought the truck to tow this trailer home. The trailer was on a job an got stolen, then we found it at a pawn shop, ( true story). Tom your comments about an overfilled tranny ring true. That was my first thought when I checked it an it was still full, after the whole undercarriage had tranny fluid on it. I was not confused until we opened the radiator an it was close to dry. I am looking here using an iPad that connects to the Internet in the cab as I go. Does not appear that the tranny fluid is contaminated. Have not found the leaking part yet, lot of wet parts under there. Can anyone elaborate on this overfilled concept?


kev2
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Dec 20, 2015, 1:22 PM

Post #24 of 25 (1849 views)
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I am overly optimistic, and its Christmas time to add, So your stuck away from home, check that coolant - the empty radiator issue - then A Hail Mary, drop trans pan inspect for grit sludge etc- replace filter refill fluid operate and get codes read. yea yea I know cost feasibility - but you know I am a hopeless optimist.
BUT tranny guys I have seen work this miracles before.


gsferraro
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Dec 20, 2015, 2:10 PM

Post #25 of 25 (1842 views)
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when a trans is overfilled, there is a chance of it coming out of the vent when it gets hot, vent is located on top of the unit by the bellhousing. Also overfilling, the trans may not shift correctly because the oil cannot exhaust fast enough through the small orffices in the unit. The trans can get hot from the converter no locking up(converter locks to engine rotation) if it slips during this process, it generates alot of heat and out the vent it comes. lock-up usually comes in around 45 mph. If i check a car with this issue and they elect not to fix it at the moment, i tell them do not drive the car on the highway. Gary






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