Tranny Screaming!

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

Ray D

Well-known member
Joined
Jun 4, 2006
Posts
1,963
Location
Boise, Idaho
It's time to start the engine and the Onan, on the Challenger, and let them run for an hour or so. It's cold, really cold, 9 deg, right now.

But, I am remembering how it went in December, when I ran them. That time it was 17 degrees, and quite an experience. The generator started right up, no problem. Then, I started the engine. It started fine, quickly, only one problem.

I was immediately startled by a very loud screaching and wailing sound. Made my teeth itch! I decided immediately, that it was the tranny. I was going to shut it down, but within seconds, the sound began to quiet down. I'd guess that in 20 to 30 seconds, it was gone. Then the sound was normal and I continued to run the engine for about an hour.

So, when I saw on the calendar that today is the day, I began to worry about that noise. Don't want to hurt the tranny. Do need to run the engine.

So, what do I do? Does the screaming mean anything other than a complaint about the cold? Do I have a problem? What is the tranny trying to tell me?

Ray D
 

Jeff

Moderator Emeritus
Joined
Apr 8, 2005
Posts
8,965
Location
SD/AZ
Ray:

Are you sure it was your tranny? The noise you describe is very similar to an old or worn fan belt in cold weather.
 

Ray D

Well-known member
Joined
Jun 4, 2006
Posts
1,963
Location
Boise, Idaho
Fan belt?  ???

;D

I can afford a fan belt!  ;D  ;D

I was digging in my pockets to see how deep they were. Not sure I could afford a tranny!  :eek:

This beast is just barely or almost two years old, counting construction. What is an old worn out fan belt doing, in there? How long does a fan belt last? I can afford probably as many fan belts as it needs, as often as it needs them, but isn't this a bit premature?

By the way, a fan belt(s) makes sense to me. I have had old worn out fan belts, before, in more than fifty years of driving. Always before on smaller vehicles. Higher pitched sound - not nearly as loud. I suppose bigger engine = bigger belts = louder and more startling.

Due for annual service, and I planned to take it in sometime in the next two weeks. I suppose I'll add fan belts to the list.

Thanks

Ray D
 

Karl

Moderator Emeritus
Joined
Mar 3, 2005
Posts
5,154
Location
Elkhart Lake, WI for the summer. Work at Road Amer
Ray D,

Not necessarily worn out. Could be just not enough tension, but once it starts to squeal it will also start to glaze, so best to replace it. Might as well get the others replaced now too while they're working in the same area. Saves on labor costs.
 

Ray D

Well-known member
Joined
Jun 4, 2006
Posts
1,963
Location
Boise, Idaho
Thanks, Ernie. I may do that. First, I'm going to open the access and see if there is anything I recognize as a fan belt. I'm not up to date on modern engines. I've looked in there to check fluids, and I can tell that there is an engine there. Not much that I understand, but I'm sure that is an engine.

Ten years ago, I bought my Volvo. I remember the salesman opening the hood, to show me the wonderful, last forever, power plant.

Well, I looked. There were some things in there that I recognized as pieces of engine, but not many. Packed like a can of sardines and there may have been some sardines!  ;) I told him to close it.

I said, "this is under warrantee. I am never going to look in there, again. I'll bring it in, when I want someone to look in there." I feel pretty much the same about the motorhome. I've looked. There are things in there that I recognize. Difficult access, for me. Lots of stuff I have no idea about. Too old to go back to school. Fan belts I understand, if I can find them.

Thanks again.

Ray D
 

Ray D

Well-known member
Joined
Jun 4, 2006
Posts
1,963
Location
Boise, Idaho
Karl:

Copy that.

That's probably what I am going to do. I don't want a fan belt to interrupt a trip, when it gets warm enough to take a trip. I'll see how long I have to wait, for an appointment. If it's weeks, I'll lube it and run it. Otherwise, new belts, next week.

Ray D
 

Lowell

Well-known member
Joined
Aug 15, 2005
Posts
2,221
Location
Tempe, AZ
You don't want to lube the belt.  You want it to grip.  It is the slippage that is causing the squeal.  A Short term solution may be as simple as spraying the belt with hair spray to get some friction between the belt and the pulleys.
 

King

Well-known member
Joined
Jan 30, 2006
Posts
354
Location
MA
The "fan belt" that usually makes all the noise on start up is really the Alternator belt.  In a Motor home, usually the alternator charges both the engine battery and the house battery.  When you first start the engine is when the load on the alternator is the greatest.  Particularly if the house batteries have partially discharged.
Art
 

Ray D

Well-known member
Joined
Jun 4, 2006
Posts
1,963
Location
Boise, Idaho
OK, Art, that makes sense. So, does this mean that the cold weather yelling and screaming is normal and I should ignore it? Or, should I still replace the belt(s)?

Ray D
 

John From Detroit

Well-known member
Joined
Apr 12, 2005
Posts
25,392
Location
Davison Michigan
It was most likely not the tranny... I know of a number of things under the hood that can be screaming even on a stick shift.  Power steering, fan belts, hydro boost pumps, vacumme pumps, air pumps, alternator, And that is just the top of the short list.  The long list is much longer
 

Jeff

Moderator Emeritus
Joined
Apr 8, 2005
Posts
8,965
Location
SD/AZ
Ray:

Replacing the belt provides another benefit. Replace all of them and keep the old belts on board as spares in case of emergency. That way you won't spend a fortune having someone figure out what belt you need, running it down and getting it installed if you break one. Having new belts means you will not need the spares for years. ;D
 

Gary RV_Wizard

Site Team
Joined
Feb 2, 2005
Posts
74,964
Location
At my Silver Springs FL home
I had that happen to me on our previous Workhorse W22. The a/c compressor clutch had seized up and the serpentine "fan" belt could not turn freely. What a screaming noise! It kept up until the clutch self-destructed about a minute later. The belt survived, though it was badly worn by the episode.  Workhorse replaced both the a/c compressor and the belt under warranty.

So you probably need a new belt, but you definitely need to find out what is causing it to scream like that. A slipping belt squeals a bit but should not make a "scream".
 

RLSharp

Well-known member
Joined
Mar 3, 2005
Posts
1,810
Location
Rochester, NY summer; Tucson, AZ winter; otherwise
Ray D said:
....I was immediately startled by a very loud screaching and wailing sound....

So, what do I do? Does the screaming mean anything other than a complaint about the cold? Do I have a problem? What is the tranny trying to tell me?

Ray,

Before replacing the belts, unless you just want to have a spare set to carry, I would have a mechanic listen to your screaming noise. You did not indicate what engine you have, but if it is Ford, there is some sort of valve in the throttle body which can make a terrible screeching sound if it goes bad. This happened to me on a Ford 460 engine a few years ago. I though it was a belt but inspection showed them to be tensioned properly (one has an automatic tensioner) and they didn't appear to be glazed. I took the motor home to Ford dealer the night before my appointment and had the mechanic start the engine first thing in the morning. He immediately recognized the "thing" in the throttle body as the noise maker. I don't know whether other engines have this thing in the throttle body.

BTW, while looking over the belts he found an idler pulley which was badly worn. I had him replace it and put on the new spare belts which I had been carrying since we purchase the motor home. The idler pulley had nothing to do with the noise. It turns out that the Ford dealer who sold me the new belts based on the VIN sold me one belt that was the wrong size. I kept the old belts for my spares.

Replacing the valve in the throttle body fixed the problem, in spite of the fact that I could have sworn that it was one or both belts making the noise.

Richard
 

Ray D

Well-known member
Joined
Jun 4, 2006
Posts
1,963
Location
Boise, Idaho
I'll be calling for an appointment, tomorrow. The unit isn't going anywhere, in this weather, so next time I start it, it will be going to annual maintenance. I have a list.

It's a Workhorse with Allison tranny.

Ray D
 
Top Bottom