Belt Slip Sound at shift from 1st to 2nd

[sleeper]

I have noticed the past couple of weeks when I am at WOT in 1st, and the the shift into 2nd occurs, I hear a very short high pitched squeel from what sounds like under the hood. This occurs if I shift from 1st to 2nd or I am in D. I do not loose any performance that I have noticed during this. I feel no tranny slippage or anything. Wondering if anyone has any ideas. Thanks.

[Bradley G]

could that be from the rear tires?

[sleeper]

I wish that's all it was. This is in addition to the tires. Tires don't always squeel. Especially on some of the roads arounds here. They just get ground down.

[Rider90]

I wish that's all it was. This is in addition to the tires. Tires don't always squeel. Especially on some of the roads arounds here. They just get ground down.
Sounds like the belt IMHO, is this only when it is moist out? or everytime...?

[looking97233]

Yep, mine does it too. Replaced the belt, it was quiet for a few weeks but has started again.

[sleeper]

Everytime.

[Rider90]

Maybe it is the replacement, looking97233? Like I recently mentioned in another thread, I prefer Goodyear Gatorback over everything else. It is a little more expensive if I recall but well worth the money. If it isn't the belt, sleeper, it could be something more serious and I hope someone else will chime in.

[cyclone03]

If you have a 300a or early 300b the alternater has a built in clutch that will make this sound at high rpm.

[sleeper]

Thanks for all the input. I will most likely take to the dealer. Even though I am out of warranty, I don't want more serious stuff to result. I am running on a SuperChip program. Shift points are set to high. I've had the program for well over a year and just now had any kind of issue. Again, thanks.

[thePunisher]

alot of the modular engines do this...it is from rapid deceleration of the ascessories when the shift occurs. the belt slips a little. if the trans shifts nice n crisp itll be worse...youll probably never get rid of it....

[DEFYANT]

My ole CVPI did that too. It is not a problem. Though on a few cases.. I heard of an accessory belt coming off. That would be a problem....

Could be your tentioner is wearing out.

[Joe Walsh]

If you have a 300a or early 300b the alternater has a built in clutch that will make this sound at high rpm.

I thought that the purpose of the clutched alternator was to eliminate the belt chirp???

[torinodan]

I thought that the purpose of the clutched alternator was to eliminate the belt chirp???I thought it was to keep the guts of the alternator from blowing out all those little holes when it's spinning really really fast.:help:

[DEFYANT]

The clutch cuts off at WOT to reduce the drag on the engine.

[Joe Walsh]

The clutch cuts off at WOT to reduce the drag on the engine.
My 300A has a mechanical one-way clutch which is non-electrical, it merely lets the alternator pulley 'free wheel' when the engine quickly upshifts a gear from 6200 rpm down to @ 4500 rpm. The alternator and its' pulley are still, briefly, spinning at 6000 rpm while the serpentine drive belt has quickly slowed to 4500 rpm after the shift. The clutch free wheels to eliminate belt chirp.

The engine management system does shut off the charging function of the alternator during WOT, thus decreasing the parasitic losses on the engine...
same as the A/C compressor.

[David Morton]

My 300A has a mechanical one-way clutch which is non-electrical, it merely lets the alternator pulley 'free wheel' when the engine quickly upshifts a gear from 6200 rpm down to @ 4500 rpm. The alternator and its' pulley are still, briefly, spinning at 6000 rpm while the serpentine drive belt has quickly slowed to 4500 rpm after the shift. The clutch free wheels to eliminate belt chirp.

The engine management system does shut off the charging function of the alternator during WOT, thus decreasing the parasitic losses on the engine...
same as the A/C compressor.Joe's right about the Alternator clutch.

You have belt slippage during the shift from accesory decelleration as mentioned before. Here's what to do.

Put on a new belt. Clean the pulleys before you slip it on and then crank the engine and look at the tensioner. If the pulleys are straight and clean, it shouldn't be bobbing much, if any. If the noise goes away for awhile and comes back, or if it doesn't go away at all, replace the tensioner. If it's bobbing a lot, there's a bad pulley, replace it.

I'm with Defyant, it's probably the tensioner.

[Blackened300a]

I had that slip sound when I would shift into second, and sometimes third, Turned out my Belt Tensioner was leaking a Grey Substance that looked like Never Seize and it was bobbing up and down a lot, I replaced it for $30 and never heard the chirp again.

[larryo340]

:banana2: My Grand Marquis started to make the same squeal on WOT after I put on dual exhaust. When I worked for Lincoln/Mercury the Continetal (they had the 4.6L 32 valve engines also) did this too when it shifted at WOT.

[thePunisher]

yep its a product of high rpm and a small alternator pulley....not enough belt contact so it cant handle rapid rpm changes...moms continental does it eveerytime!

[cruzer]

I've had this chirp since day one----now have 76,000 mi on the MM--no problems

[rvaldez1]

I've had this chirp since day one----now have 76,000 mi on the MM--no problems

Same here, every 4.6L V8 I have driven does this, even the 3V Explorer. What I have done is always replaced with gatorbacks. But I have noticed that there is a very small amount of belt rub on the drivers side block of the car. So maybe it isnt a belt slip but a belt rub.

[Joe Walsh]

Wow! This is another revived old thread...

Maybe we will nickname the resuscitators:

DEAD THREAD HEADS

;)