Allison whining 3-4 shift

[quinton]

Transmission just started doing this, sometimes on the third to fourth shift it makes a whining sound, like when you hear frequency through your radio with a aux cord or something and it gets louder with the rpm, it's just like that but sometimes it will do it right after the shift. Sounds like it's electrical trying to engage something but the truck runs perfectly fine. Could it be the NSBU switch going out? Sound is coming from right under the driver floor board.

 

[quinton]

Nobody?

 

[x MadMAX DIESEL]

Edit!!!! Disregard my thoughts on tc if you read that. Do you have a single fixed geometry turbo? They can make a funny noise, mine did after certain shifts... Slick bore large frame turbo.

 

[quinton]

No I don't. It's something with the trans. But runs perfect.

 

[quinton]

It also does it every now and then when I come to a stop.

 

[mike diesel]

Sounds like the pump is on its way out.

 

[quinton]

Wonder if I will be able to see it in a log even knw everything still shifts fine. Might have low pressure or something.

 

[mike diesel]

My buddies truck started a few weeks ago. It whines at idle and upto about 15-1600 rpm then goes away. We're pulling it in the next few weeks but so far it hasn't showed any signs of decreased holding ability.

 

[quinton]

Ya mine just does it every now and then and sounds like it's engaging something but when it whines then sounds like it engages it's nothing different. I can kick it into neutral while it's doing it and it will stop whining.

 

[DPC]

How long ago was your tranny built? Check the cooler fittings on the side of the transmission to make sure they are tight.

 

[quinton]

I built it 4 years ago. Checked em and they are good.

 

[jc1843]

Possible the internal filter is partly restricted-.

 

[quinton]

It ain't the filter, it's brand new, and now it just started making a grinding sound.. Does it in second, fourth and reverse. I think it's my TC that's where the grinding sound is coming from

 

[rgullett83]

I wonder if you have a torrington that has failed. When you say filter is new are you referring to soon on or internal? May want to pull the pan and check for debris.

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[quinton]

I wonder if you have a torrington that has failed. When you say filter is new are you referring to soon on or internal? May want to pull the pan and check for debris.

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Both are new, fluid is new to. I just went through the whole trans to replace the P2. I'm pretty sure it's not a Torrington bearing because it's not loud at all and it only does it in those gears then goes away. It's strange truck still drives normal to. Normal temps, no low fluid, still shifts fine and smooth, no slippage. It's parked though now so I don't tear anything else up just in case. It doesn't whine anymore though now. Lol.

 

[Bustedknuckles]

Id pull it apart now to minimize damage. I HIGHLY doubt its the torque converter.

 

[quinton]

Id pull it apart now to minimize damage. I HIGHLY doubt its the torque converter.

What else could it be? It's coming from bell housing area

 

[Bustedknuckles]

What else could it be? It's coming from bell housing area

Pump. The torque converter would whine all the time, guess you could swap it out with another one and just hook up the least amount of stuff possible to start and run it to rule that out.

 

[quinton]

I might just replace the pump and send the tc off to get re stalled since I have one free restall with it.

 

[rgullett83]

If you just had it open, it's possible to have installed a bearing improperly. Hearing it in certain gears rules out the converter and pump by my thinking, however I have been wrong before, curious to see what you find, keep us updated.

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