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Tranny funny when cold


droger03

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I have a weird problem. My tranny shifts fine in the morning when I first start out on my commute and then I start to loose 4th and 3rd. It happens after about 20 minutes of driving. I have done the shift solenoids and it still does the same thing. Is there something else that could be wrong?

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I forgot to mention that this car is the 97 D'Elegance that I just bought and not my 96 Deville

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Check the trouble codes, if you dont have any codes its likley a problem that GM couldn't anticipate, wich seems to be rare. Im not an expert on tranny's but 20 minutes is about the time it takes the northstar to heat up, sounds like it might be temperature related..scotty should be able to help you out.

A.J.

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I checked the fluid level and it is fine. It does not go into limp home mode because it still is trying to shift into third and 4th. There is a really bad whine in the transmission coming from the left side of the car. it is present whether the tranny is hot or cold. It's funny though because the transmission works fine in the morning when it is cold. It is only after it heats up about 15-20 minutes into driving.

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I checked the fluid level and it is fine. It does not go into limp home mode because it still is trying to shift into third and 4th. There is a really bad whine in the transmission coming from the left side of the car. it is present whether the tranny is hot or cold. It's funny though because the transmission works fine in the morning when it is cold. It is only after it heats up about 15-20 minutes into driving.

A whine is indicative of a pressure or pump problem if I am not mistaken. That is an important symptom. At what mileage was the fluid and filter changed? Who changed it? Who did the solenoids? Is it possible that your filter is improperly installed, they can be tricky to install correctly. After 15-20 minutes of driving do you LOSE third and fourth gears spontaineously while you are driving at highway speed or when you start from a stop? Are you sure you don't have ANY codes.

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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no codes. I did the solenoid job myself. It was quite easy. I checked the check balls three times before putting it back together and then I ripped it apart and checked them again when I started having the same problem. I start to loose third and fourth when I am on the freeway. first 4th goes and then 3rd starts to slip. The whine in the transmission is constant no matter what speed I am going or how cold or hot the car is.

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Hmmmm....what about the little black filter & bracket that came with the solenoid update kit..Did you install that correctly? (I ran into some trouble b/c I didn't put the bracket on). However you said the problem existed before you did the solenoids correct? and you replaced the solenoids to see if indeed that was the problem?

A.J.

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no codes. I did the solenoid job myself. It was quite easy. I checked the check balls three times before putting it back together and then I ripped it apart and checked them again when I started having the same problem. I start to loose third and fourth when I am on the freeway. first 4th goes and then 3rd starts to slip. The whine in the transmission is constant no matter what speed I am going or how cold or hot the car is.

Ok i just checked my manual.

There are 2 types of whines one that is constant and one that varies with RPM. It seems that the whine that is constant involves the torque convertor and the whine that varies involves the oil pump system and pressure (as I noted above).

Yours is constant from your description (a better whine if you ask me than one that varies and involves the pump). To varify that the noise is internal to the torque convertor place your left foot on the brake with the selector in DRIVE. Momentarily stall the engine. Torque convertor noise increases under load. I think what they mean by stalling the engine is to give the car gas with the brake on. I don't know how much gas, however, maybe someone will chime in here and give information about what STALLING the ENGINE means...

Looking further, I find a symptom, LOSS of DRIVE, and the top cause is TORQUE CONVERTOR (yea, now we are getting somewhere), and the reasons, broken lug (not likely), failed lug weld (NO), sheared lug bolts (NO), worn turbine shaft splines (maybe), low fluid (you said OK), pump hub cracked or broken (hope not), internal failure (possibly), closure weld failure (not likely), and cover cracked at weld (not likely)... Do some testing as I descibed above and see what you find... Mike

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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The whine does actually rise and fall with engine rpm. It is not constant. Does this mean that it is the pump assembly. I recently had the side cover off and Sunday to checjk to see if the pump was clogged with something but it looked ok. Could it be that there are no visual signs to a failing pump assembly? If the pump is bad can it be replaced with a new one that I can find at the cadillac dealer. The one funny thing about the whine is when the tranny is shifting through gears, it actually gets louder between gear engagements.

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Ok, I just took the car for a highway spin with the radio so I could get a definite feal for what it was doing. It seems that it does start slipping after about 15-20 minutes of driving. But here's the thing, It doesn't slip while I'm accelerating :huh: If it starts to slip and I give it a good amount of gas it goes away. Another sympton is that when I'm cruising at about 65 and It starts to loose fourth, I'll drop the gear selector down to third so it won't jump. But if I take my foot off the gas and the RPM's fall, It starts to loose third as well until I accelerate again.

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The whine does actually rise and fall with engine rpm. It is not constant. Does this mean that it is the pump assembly. I recently had the side cover off and Sunday to checjk to see if the pump was clogged with something but it looked ok. Could it be that there are no visual signs to a failing pump assembly? If the pump is bad can it be replaced with a new one that I can find at the cadillac dealer. The one funny thing about the whine is when the tranny is shifting through gears, it actually gets louder between gear engagements.

The pump assembly can be leaking internally, something could have gotten into it and scored it negatively affecting its ability to maintain proper pressure, or a bearing could be shot which could affect clearances that both would cause scoring and pressure loss its not necessarily related to clogging. I do believe that a replacement pump can be purchased by a tranny rebuilder, and I imagine you could purchase one also through the right channels. The dealer may even have one but typically the tranny needs to come out of the car as the pump is directly behind the torque convertor. I am not sure if that is true anymore with the NS system but I do believe that it will require that you R&R the tranny.. The pump should be taken apart to see what was wrong, and to determine the possibility that debris may have been circulated. What did you find in the pan when you dropped it any filings? I will look at my manual when I get a chance. A pressure test should uncover a problem...

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Ok, I just took the car for a highway spin with the radio so I could get a definite feal for what it was doing. It seems that it does start slipping after about 15-20 minutes of driving. But here's the thing, It doesn't slip while I'm accelerating :huh: If it starts to slip and I give it a good amount of gas it goes away. Another sympton is that when I'm cruising at about 65 and It starts to loose fourth, I'll drop the gear selector down to third so it won't jump. But if I take my foot off the gas and the RPM's fall, It starts to loose third as well until I accelerate again.

It certainly sounds like a pressure problem, the reason its ok when you accelerate is because you are increasing the pressure. I would have a reputible shop do some pressure diagnostics for you, and I do mean reputible. I also would avoid driving the car as much as possible when you lose gears its possible that you are spinning your clutch packs and doing a number on them, soon you will need a major rebuild.. I almost feel of my chair a moment ago when you said you did 65! :lol:

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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I looked at a blow-up view of the 4t80-e and it looks like the pumps is on the side of the tranny beneath the side cover. If this is true I had the pump off and held it in my hand this past Sunday. I spun the gears and it seemed OK, but spinnign in my hand and while the car is in motion is two different things. I'm just worried that if I replace just the pump, it might not solve my problem. Though what you say does make sense. I will try to price a new pump for it tommorow at the local dealer here is Columbus, Ohio.

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Please don't throw parts at it based on this conversation, I will feel terrible if it is not the problem. I will look at my manual and let you know what I find. I would definately have a shop do a pressure test on it, a pump rarely fails. Its possible that you have a nicked or damaged o-ring on the pump assembly, did you notice any o-rings on any covers? Think pressure test before buying a pump.. Nite

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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One symptom that I forgot to mention scotty is that there is a 1-2 second delayed engagement in to drive or reverse. What are your thoughts on that.

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One symptom that I forgot to mention scotty is that there is a 1-2 second delayed engagement in to drive or reverse. What are your thoughts on that.

Thats also a symptom of low pressure...

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Droger,

Diagnosing by computer is kind of difficult. but I'll put in my 2 cents worth. (Which isn't much after all the inflation the last 50 years. ;) )

It sounds like the pump is starving for oil, and as the oil get hot & thinner, you get lower pressures and then start dropping the higher gears.

Just curious, is the TCC working? It is easy to check (before the trans starts acting up). Get up to crusing speed and while holding a steady speed use your left foot and just lightly depress the brake pedal, not enough to apply the brakes, but enough to where they would almost start to apply. Pay attention to the RPM and listen. You should get a noticable rise in your RPM and you should hear and feel it also. If there is no change, your TCC isn't engaging and this will cause the torque converter to get REAL HOT! :o If this is happening, you oil is thinning out and you are getting the results in loss of oil pressure. I have seen torque converters that got so hot that they burnt the paint off of them. :blink:

The other and easiest check/fix would be to change the pick-up screens (some call them filters) and the seals where the screens go into the transmission housing. A partially blocked, or poorly constructed aftermarket suction screen, or a cracked screen or screen to case seal could cause your problem.

While you have the pan off, make sure that the internal drain plug has been reinstalled. (The one that drains the side case.) I'm not sure what leaving that plug out would do, but as the tranny fluid gets hotter and thinner, it would allow more of it to drain back into the bottom pan, then the pumps would have to pump it back up, in a never ending circut. The more that you pump an enclosed fluid, the hotter it gets. (It's a long shot, but probably worth a look).

Did I understand that the car had over 300,000 miles on her? If so it could just be that her time is up. :(

Good Luck, I hope that it is something simple (and cheap). Let us know what you find.

Merry Christmas to ALL!! :)

Britt

Britt
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Droger,

Diagnosing by computer is kind of difficult. but I'll put in my 2 cents worth. (Which isn't much after all the inflation the last 50 years. ;) )

It sounds like the pump is starving for oil, and as the oil get hot & thinner, you get lower pressures and then start dropping the higher gears.

Just curious, is the TCC working? It is easy to check (before the trans starts acting up). Get up to crusing speed and while holding a steady speed use your left foot and just lightly depress the brake pedal, not enough to apply the brakes, but enough to where they would almost start to apply. Pay attention to the RPM and listen. You should get a noticable rise in your RPM and you should hear and feel it also. If there is no change, your TCC isn't engaging and this will cause the torque converter to get REAL HOT! :o If this is happening, you oil is thinning out and you are getting the results in loss of oil pressure. I have seen torque converters that got so hot that they burnt the paint off of them. :blink:

The other and easiest check/fix would be to change the pick-up screens (some call them filters) and the seals where the screens go into the transmission housing. A partially blocked, or poorly constructed aftermarket suction screen, or a cracked screen or screen to case seal could cause your problem.

While you have the pan off, make sure that the internal drain plug has been reinstalled. (The one that drains the side case.) I'm not sure what leaving that plug out would do, but as the tranny fluid gets hotter and thinner, it would allow more of it to drain back into the bottom pan, then the pumps would have to pump it back up, in a never ending circut. The more that you pump an enclosed fluid, the hotter it gets. (It's a long shot, but probably worth a look).

Did I understand that the car had over 300,000 miles on her? If so it could just be that her time is up. :(

Good Luck, I hope that it is something simple (and cheap). Let us know what you find.

Merry Christmas to ALL!! :)

Britt

If the TCC isn't working wouldn't that set a code?

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Scotty,

It should set a code. But I have seen things that should set codes before & not set them, for whatever reason. :(

The more that I think about it, a missing internal drain plug has it's possibilities.

Britt

Britt
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The TCC workis fine while the tranny is cold. IT only stops working after the tranny heats up and starts loosing gears.

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I just looked through the manual, unless I am mistaken, neither the primary or secondary pump is detailed as an ON-CAR repair. As I mentioned previously I would have a pressure test done asap. While they do the pressure test have them watch the pressure reading, if the pressure reading varies with the whine, its pump related. Low pressure according to the manual is the result of the pump gasket or cover leaking. While its possible that you are not setting codes that SHOULD be set, if your tranny fluid was overheating and thinning out you would set a PO218 code, be sure to smell the fluid and see if it smells burnt or if its dark. Mike

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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It is possible to do the pump assembly replacement in car. Just follow the procedure for replacing the vss sensor in the archive. After you lower the cradle and remove to side cover, you actullay remove the pump assembly in the process. Also like I said, I had the unit out this past Sunday for visual inspection. I have a new pump on the way from a local gm dealer that owes me a favor. The part # is 8685141 and it comes with the pump body and the upper valve body assembly. They are only charging me $125.00. I'm going to drop the cradle tonight and pull the old pump out so It will be ready for install tommorrow.

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