trany (or turbo) "howl"?

steve3007 · Post by **steve3007** » 04 Feb 2006, 18:46

My 98 T5 has what I can best describe as a "howl" noticable at low speed (< 10 mph). I am trying to figure out if it is the trany or the turbo. The frequency is proportional to engine speed.

When I'm idling along and drop it into neutral, it goes away immediately which makes me suspect the trany. I can rev the engine in P or N and no howling sound.

My 850 (non-turbo) does not make this noise and has (I believe) the same transmission.

Anything to worry about? Seems to shift fine and the fluid level is good.

saltydog · Post by **saltydog** » 05 Feb 2006, 10:06

don't laugh, but how's your tire wear? Check to see if the inside or outside of the tread face is feathering - front & rear....may surprise you.

steve3007 · Post by **steve3007** » 05 Feb 2006, 14:28

I doubt the tires are a factor here. If I'm rolling along in gear and then drop into neutral and continue to coast along, the howl goes away.

Post by **pfeener** » 05 Feb 2006, 15:30

Doesn't sound like the turbo. The turbo doesn't come into play at low speeds. Does the noise go away as the transmission shifts up from 1st to 2nd? How about 2nd to 3rd? What's the howl like at 30 or 50 MPH? If it goes away after the transmission shifts from 1st to 2nd, it's probably the planetary gears in the transmission, which means it's time for a swap-out of the trannie.

steve3007 · Post by **steve3007** » 05 Feb 2006, 21:19

The howl is slightly noticable at speeds < 10 mph. It may be still there at higher speeds but wind noise makes it difficult to tell. It is certainly low in accoustic volume - you have to listen to it carefully. My gut feel is that it is there in all transmission gears but I'm not completely certain.

What other symptoms would I be looking for to suggest the planetary gears are gone? As I said earlier, it seems to shift fine into all gears (for now).

It only stands out because my 850 does not make the same noise.

Post by **pfeener** » 05 Feb 2006, 22:22

How does the noise change from acceleration to deceleration? Is it louder when you accelerate. Is it louder when you accelerate faster? It could also be the torque converter, which is usually more of a whine than a howl. Try putting the car in "Winter" mode which starts it off in 3rd gear and see if the noise is still there. If it is the torque converter it should be louder starting off in 3rd gear. I assume you've checked the fluid level in the transmission. How does the fluid look...should be pink or light tan if it has some miles on it. If it's black and/or smells burnt, the transmission fluid should be flushed. The generaly accepted flush interval is 30K miles.

When all is said and done, it might just be a transmission that has a little bit of noise to it and will function fine. When my S70 was new it had a slight whine in the trannie at about 30 MPH. It now has 186K and the noise is gone.

Post by **pfeener** » 05 Feb 2006, 22:27

One more thing. Does the noise change when your transmission shifts from 1st to 2nd. Accelerate smoothly on a quiet road and listen and feel the shift point. Does the noise change. Also the planetary gears don't have anything to do with the actual shifting of the transmission. The gears stay engaged at all times and provide for the different gear ratios in the transmission.

Post by **matthew1** » 06 Feb 2006, 14:30

Could it be the mysterious ghostly moan?
https://www.matthewsvolvosite.com/chat/p ... light=moan

steve3007 · Post by **steve3007** » 08 Feb 2006, 16:45

While I characterize the sound as a howl, some might call it a whine.

Upon further investigation, I have determined that it is only audible when in 1st gear, frequency is proportional to speed, and does not change is volume when decelerating or accelerating.

Since the noise is not present when I rev the engine in P or N, that would suggest ruling out Matt's suggestion of the "ghost moan". It goes away when the trans shifts into second.

Fluid is good and I just flushed it myself a last month (it was present before I flushed the fluid which incidently looked pretty good suggesting it was changed not to long before I bought it in December.

Seems highly likely this is something related to my trany but I'm not sure I should be worried or not.

Post by **pfeener** » 08 Feb 2006, 20:21

i think there's a strong likelyhood the "whine" is coming from the planetary gear system in the transmission, since it's only there in 1st gear, I would just drive it. It may have been there since the car was new. If it starts to get worse you may need to take some action, but I would wait and see.