Thread: Need Help Identifying Transmission Whine

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  1. #1 Re: Need Help Identifying Transmission Whine 
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    Alright, here are my findings from this weekend:

    I listened to all of the pullies, alternator, power steering, water pump, idler, a/c compressor, and none of them seemed bad. I was pleasantly surprised to hear the water pump makes a soothing swooshing type noise through the scope.... kinda helped to relax me with all this aggravation But just to be sure, I did take the serpentine belt off and ran the engine (briefly) with no belt, and the noise persisted, so I am sure it is nothing being driven from the belt. (Wish I would have thought to do this before I replaced the PS pump and wasted that time and $).

    Next, I moved on to the transmission, I listened to the bell housing, and the noise was a very mild (faint & non-distinct) grumble, did not sound like a whine through the scope, but more like a bearing possibly? The noise seemed slightly louder to the far driver side of the housing, as opposed to clsoer to the middle of the housing straight down from side of the engine intake. I dont know, as I am new at using the scope to listen for noises, so I am not sure exactly what I should be hearing should sound like. I listened through the trans pan under the car, and it was very similar to the bellhousing from the top. Then I listened to the trans cooler lines (the metal ones right near where they exit the trans) and I could hear a distinct grumble through both lines, kind of sounded a little like a bad bearing type noise, or a bearing with one ball removed and replaced with a small rock instead. The noise was loudest near the trans, and inauduble in the trans cooler lines at the radiator (they are isolated by rubber hose). I think this tells me the noise is certainly in the trans, and not just the coolant flow through the lines. And very near where the lines go into the trans.

    There is no difference in the noise regarding hard or soft accelleration, so I do not think it is the torque converter, at least these tests dont appear to point in that dirrection I dont think, but I will deffer final judgement to the expert.

    When it is making the noise, I put it in 1st, and there was no difference in the noise. It was still present, but no louder or softer.


    So here is my 3 part question:

    1. What in your opinion is bad and/or a likely culprit? Is there a way to verify this before or during the repair so I dont get it back together and still hear the whine?

    2. Is it servicable through removing the side cover, or do I have to pull the whole trans from the vehicle?

    3. If I choose to do this repair myself, are there any special tools I will require that a normal well stocked tool chest for someone that dosent do trans work wouldnt have?
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  2. #2 Re: Need Help Identifying Transmission Whine 
    Transmission Expert Trannyman95's Avatar
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    Just to make sure, you DO have this same exact noise whether in Park or Neutral OR sitting still with foot on brake pedal and in gear correct? If the same noise and volume of noise is present in any gear position and sitting still with your foot on the brake then it is likely servicable without remove the transmission completely which means removing the side cover should point to a problem. Once you pull the lever into reverse or drive with your foot on the brake pedal and not moving then nothing inside the trans spins as far as geartrain goes, so all that leaves is the pump shaft and pump.... you mentioned it didnt seem to get louder with load so we will not worry about the converter at this point. Now that "when" has been established and our possibilities I answer you questions in order

    1. With your mileage there is likely a bit of wear on everything, but as mentioned above only your pump and pump shaft is spinning and working in gear and not moving, which you mentioned still exhibits the same noise. I very rarely see pumps fail in these transmissions unless a lot of metal is in the systme from internal damage. One thing I do see from time to time is a bearing inside the pump rotor in poor condition or falling apart. This will certainly cause noise and also tear into a sleeve/support that is pressed into the valve body and used for a guide for the rotor to sit on. When this gets pitted it will always make noise. The pump shaft itself more-less just floats and there isnt much that supports it or could cause noise, but he splines on the converter side will wear over time and should be replaced if worn. If the above is OK after apart and inspected you are left with the pressure system. The pcm controls the pressure control solenoid inside the trans and if it is bad or failing it can cause high line pressure which will also make the pump whine. Internal wear and overall low line pressure will cause the pcm to raise line pressure to overcome slippage from wear over time and if it is out of its acceptable limits then it will go into limp mode with max line pressure.

    2. As mentioned above due to when the noise is present this problem should be able to be fixed just removing the side cover

    3. The only obstacle is you will need some type of engine support to do this as you will have to hold the engine and trans up while lowering the support craddle from under the front of the car. Sometimes you can get away with just loosening the passanger side cradle bolts and completely removing the drivers side bolts and allow everything to relax at an angle to get the side cover off. Other than an engine support bar the transmission itself isnt going to require any special tools for what you can get into through the side.
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  3. #3 Re: Need Help Identifying Transmission Whine 
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    Correct, noise is present in Park, or Neutral, or standing in gear, as well as while driving.

    When I just flushed the trans and pulled the pan, I did not see any chunks of metal, only alot of grey mucky stuff near the magnet that I can only assume is about 135000 miles worth of friction material? That was all cleaned prior to reassembly, and it was all stuck to the pan around the magnet area.

    Also, I dont know why I didnt mention it sooner, but when I did the trans flush, I used the trans to pump the old fluid out into a bucket while I dumped the new fluid in through the fill tube. It pumped so fast that by the time I poured a 1 gallon jug in through the funnel, it had already pumped out about 2 or 2.5 gallons. I had to shut the engine off to catch up. I had to repeat that twice. In total I used 20 quarts of trans fluid to do the flush, and refill the system after dropping the pan. I am going to ask if this sounds like the appropriate rate of fluid flow for an idling engine, but I'm not sure if thats enough information to guess on or not. And also, since the trans pump is clearly performing its job in this regard of moving fluid, would this point more to that bearing issue? Or will a failing trans pump still move fluid this well?

    Also, is there a way to rule out the PCM before the side cover is removed?

    While thinking about the relationship of temperature to noise, and it is very consistent in that it still makes no noise while cold, I am thinking that this lends itself to not being the bearing, and being more of a valve problem? Does that make sense, or am I thinking about it wrong?

    Thanks again!
    Last edited by 01GPGT; 06-25-2008 at 10:20 PM.
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