2004 Chevrolet Impala 4T65E transmission whine in second

[Kennedy01]

A friend and customer of mine has a 2004 Chevrolet Impala with a 3400 V6 and the 4T65E transmission, about 115K on the car as of now. About twice a month he travels to his family's land to check everything over, and to get there he has to ascend a small mountain. To pull the grade he uses manual second gear, then shifts back to overdrive once he reaches the top where it plateaus. You really need to pull this ascent the way he does in this car. When he pulls this grade the transmission begins to whine only once engaging manual second, and by this time we've driven close to thirty miles. After reaching the top and shifting back to overdrive, it still whines when the car shifts itself to second, whether upshifting or downshifting. The transmission never slips, shudders or struggles to pull, just whines. We get there and park the car, I rode along because he wanted me to hear the noise and I had nothing else going on. Only took him about half an hour to scan the place over. After the car sat that time we headed back home, and the noise did not return at any point regardless of second gear engagement. The transmission fluid is full, and was serviced last year using Mobil 1 ATF, which doesn't meet Dexron 6 but does meet Dexron 3 specs. It also has a bottle of Lubegard added. The mountain climb is the only time it ever whines, but it gets pretty loud.

I do some light mechanic work as some of you know, but I am not a transmission man. I can change the fluid and change the whole units, but I've never actually cracked one open beyond changing the internal filter. Any ideas on what the whine might be? Perhaps the Mobil 1 is too thick? I really don't have an answer for him.

Thanks.

 

[Slick3914]

It’s the pump whining due to the trans calling for max pressure. Those transmissions were not GMs best effort.

 

[GMBoy]

As already said - that is pump whine under the way it's being abused. Keep it in D and let the car decide which gear to run. Most likely in a short time the trans will probably fail unfortunately. That was never a good transmission and rarely make it past 100-150k miles. Just my opinion but the real guru here is @clinebarger so if he chimes in - TAKE his advice!

 

[JavierH19]

He should just let the computer decide what to do. It can take itself out of OD and downshift 1 or 2 gears if it needs. Tell him to stop abusing the heck out of poor thing by doing that to it.

 

[clinebarger]

That is a weird one....

I can't think of a situation where it would default to max pressure only in 2nd gear & make the pump whine.

I'd guess a bad torrington bearing that's only loaded in 2nd.....But, It would make noise anytime it's loaded regardless.

Wonder if a Carrier/Gearset is getting hot & making noise 'til it cools down? Will likely be seen in the ATF temp.

 

[Number_35]

Is he trying to maintain highway speed up the mountain?

I wonder if the whine would go away if he took it slow enough that the transmission selected a lower gear on its own.

 

[Kennedy01]

I will probably tell him to find a different way to the property. There's an alternate route but it adds about ten miles to the trip. No steep grades though.

He isn't trying to run highway speeds, max speed up this windy little road is 40 if you're lucky. He selects second as the makes a low speed left hand turn, so it's not slamming down into gear.

Moving forward I'll tell him to avoid the climb and we may go suck some fluid out and add another bottle of Lubegard. Thanks for the input.

 

[Kennedy01]

That is a weird one....

I can't think of a situation where it would default to max pressure only in 2nd gear & make the pump whine.

I'd guess a bad torrington bearing that's only loaded in 2nd.....But, It would make noise anytime it's loaded regardless.

Wonder if a Carrier/Gearset is getting hot & making noise 'til it cools down? Will likely be seen in the ATF temp.

I thought it was odd myself. You'd think it would be ever present but aside from this climb it's quiet and operates normally do have any recommendations for putting in a temp gauge?

 

[D60]

At the risk of throwing out the generic interweb suggestion, is an aux trans cooler an option?

 

[clinebarger]

I thought it was odd myself. You'd think it would be ever present but aside from this climb it's quiet and operates normally do have any recommendations for putting in a temp gauge?

You can monitor ATF temp with a scan tool.

 

[Kennedy01]

At the risk of throwing out the generic interweb suggestion, is an aux trans cooler an option?

I'm sure I could install one for him if he chooses to do such. Pretty sure there's ample room for a cooler on this car and I can tie into the lines at the transmission.

 

[Kennedy01]

You can monitor ATF temp with a scan tool.

I should have been more clear, I meant a permanent gauge.