Allison Whine

[supraman]

Hi, I am new here (just bought a 2001 Silverado 2500 HD and I'm very excited to see what it can do)

 

Wanted to know if anyone has experienced a constant whining Allison transmission? It will change with RPM change. Very loud at idle and you really can't hear it at 40-50mph. I was told it's a pump of some sort and it's been this way for a long time with no issues.

 

Is it safe to drive on it like this, or should be fixed immediately? Any ideas of what it really may be?

 

Interesting discussion on an internet search I did:

http://www.thedieselpageforums.com/tdpforu...hp/t-23067.html

 

I will replace the tranny filter ASAP just in case, but I highly doubt the whine would come and go perfectly with RPM if it was an air leak in the filter.

 

HELLO and HELP!

[pwall]

Sorry can't offer any opinion/advice regarding the transmision, nonetheless, welcome to

[supraman]

thanks man

 

TTT - will add that the whine I am referring to above is quite loud and constant, gets faster/higher with RPMs. It is not a fuel pump whine I know that. Does not flux with turning, so not PS pump. It radiates from tranny area.

 

I am going to change filter tonight, but hoping to hear if anyone else knows Allison tranny's and what this could possibly be. I need to identify the issue, cost to repair and risk running on it.

 

thanks!

[dewfpo]

I guess it depends on loud it is. I have an '05 and the Allison makes a definite whine all the time. You can't hear it at speed but tooling around town it's there, sitting at idle in gear it's there. It took a while for me to get used to it. Those with diesels don't seem to notice it as much since the diesel noises mask the trans noises but those of us with the gas engines hear it loud and clear. In '06 they redesigned the the gears and something in the pump (I think) when they went to 6 speeds and they are noticeable quieter.

 

Change out your spin on filter and make sure you check your fluid level when the transmission is HOT. The ATF level should be in the middle of the hot range on the dipstick.

 

DEWFPO

[supraman]

Oh, I have the 8.1 forgot to mention that.

 

it's not like a turbo/BOV whine that is swooshing, it's quite noticeable and almost as loud as the exhaust at idle. It sounds like a fuel pump whine but 10 times louder and it varies with RPM.

 

I checked the tranny fluid and believe it was okay, but will check again. Plan to do filter tonight. Hoping that in my original post the filter could have a air leak causing the sound but I'm really not hopeful about that! LOL (fluid would come out if it wasn't air-tight I would assume!).

[SpeedyV]

Oh, I have the 8.1 forgot to mention that.

 

it's not like a turbo/BOV whine that is swooshing, it's quite noticeable and almost as loud as the exhaust at idle. It sounds like a fuel pump whine but 10 times louder and it varies with RPM.

 

I checked the tranny fluid and believe it was okay, but will check again. Plan to do filter tonight. Hoping that in my original post the filter could have a air leak causing the sound but I'm really not hopeful about that! LOL (fluid would come out if it wasn't air-tight I would assume!).

I have the same whine ('01 8.1L/Ally w/101K). It's very noticeable at idle, but I don't hear it over my exhaust when I'm moving. I have read that the pumps in the early Allison-equipped pickups were louder than later models. The local Chevrolet dealer listened to it and looked it over; everything appeared normal. I'm not worried about it, but I do plan to switch to TranSynd to prolong its life.

[supraman]

And then there were 2 LOL. Looks like SpeedyV and I are the only 2 having this very loud annoying tranny pump issue that really isn't an issue?

 

I can confirm that my tranny temps stay at 150 degrees for 1-2 hours of highway driving. So tranny seems perfectly operational. This would support those findings by the dealer, and this was performed by the previous owner of my truck as well. But I never trust things to a dealership or garage necessarily.

 

I am really more concerned why it's whining, what is it exactly? And compared to a normal quiet one what is this noise doing in term of damage/risk?

[Paulie G]

I've got an 01-8.1-ally with 68K with the same noise. When I got it with 40k on it I thought something was wrong too. When I start my truck around other people they ask me whats wrong with it. Standing in front of the truck the tranny is the only thing you hear. I don't hear the stock exhaust till I walk back by the tailpipe or the back of the truck.

 

My neighbor's truck (01-8.1-ally) sounded the same as mine so I just excepted it

 

Paulie

[supraman]

exactly, so that makes 3. I have 130,000 on mine and you only 40k at the time until now 68k.

 

But neither of you 2 understand fully why it's OK to have this whine?

 

I'm looking for answers, I can't risk being stuck on a 4 mile long hill transporting 10,000lbs and discovering it was an issue

 

Hope more chime in!

[Paulie G]

exactly, so that makes 3. I have 130,000 on mine and you only 40k at the time until now 68k.

 

But neither of you 2 understand fully why it's OK to have this whine?

 

I'm looking for answers, I can't risk being stuck on a 4 mile long hill transporting 10,000lbs and discovering it was an issue

 

Hope more chime in!

 

 

Don't forget my neighbor.............That makes 4

 

I thought I heard something about the large gears used in the Ally that makes it more noisy (this is something I heard, not something I know)

 

Why don't you call Allison Transmission and see what they have to say?

[supraman]

you think Allison would provide me information? I'm guessing they aren't going to spend time walking through symptoms with me over the phone... they'll probably tell me to take it to a local tranny specialist...

[BlackSilver]

My first Allison (an '03) came with a short VHS video explaining and highlighting some of the 'unusual but normal' sounds I might hear from the transmission. That was one of them, and after 138,000 miles of hard work it still was there. My current Allison (an '08) didn't come with a video and doesn't have that particular sound.

[supraman]

did the VHS feature a noise like a vacuum-cleaner looping/stuck on a shoe string repeated quicker with rising RPM? lol I just did some more listening and it really does sound as loud as a vacuum cleaner and I could almost tell it was "looping" as the pitch would change at a certain interval, at a certain rpm. At 30-40mph the interval is so quick and pitch rises so much I can no longer hear it over the engine/exhaust until I get back under 30mph.

 

UPDATE - I just swapped the tranny filter, noticed the magnet washer on the post, so I left it on. Not sure if there is a certain direction it should be in (up or down, can't recall if it was curved). This did NOT fix the issue, so still confused!

 

I appreciate all the feedback, keep it coming!!

[Beels]

I've got an 01 8.1 Ally as well (151,000 mi) and it whines. Much like others have mentioned. Real noticeable at slow speeds, but not at highway speed. I'm good firends with the shop foreman at the GM dealer here and he claims it's normal. Something about the vane design on the early transmissions in this application.

[supraman]

thanks for chiming in Beels. I wonder what years this affects, mine is 2001.

 

I should try to get a sound clip of it, because it would be good for everyone to know. Or maybe someone else can do it. I think my cell phone can hmmm.