Belt slips when shifting from 1st-2nd???

[mohrnormal]

My serpentine belt is in good condition. This has been happening over a year now. It only occurs when I am standing on it. I asked ford about it and they said they have never heard of this problem before. I have several ideas. get new belt or tension pully, but I was wondering if anyone else has seen this or had this problem themselves?

Thanks!

[Thomas91169]

yeah i dont blame them, why a belt would slip during a shift, and only during the 1-2 shift, and not when youre just free-revving or when cold would baffle me as well, especially if the belt is in good condition and the tensioner is working.

are you absolutely positively sure its a belt and not the intake making a whistle that sounds exactly like a belt slipping? i had a dsm, and the ps/alt belt slipped all the time, new belt, alt, didnt matter. its a dsm thing, and i know what it sounds like, its a sound file tucked in my head that basically played every day for a couple years, and when i installed the intake on my GT, it sounds just like that when its warming up, and when i take off from a stop between 8-1100rpm at light throttle. freaked me out the first time, but i kinda like the whistle now, guy asked me if its my vortech sq(super quiet ) supercharger in the mall a while ago cause he heard me take off from the stop.

[S281-335]

My 96 S281 has done this pretty much since new. When I'm on it and speed shifting it will do it when 2nd and 3rd gears hit. Is your's a stick? I've got 3:55's and I'm heavy. I think the 4.6 is "shocked" by the violent gear changes and the accessory drive is where it shows up. I think Ford changed the belt tensioner design at some point, I may be wrong on that, but I think I remember that from somewhere. It may have been a factory bulletin. I've even heard of 4.6's loosing the belts at the track while racing. Mine is a droptop so I know when and where this sound is comming from. There is a range indicator on most tensioners, see if its in range, there are brackets and a pointer on the front of it, do it with the car off! If its bad or you cant live with it, try a new Ford belt and a new Ford tensioner, not a parts store remanufactured unit. New Ford. I wound up using something to enhance the belt grip for awhile. Good luck and let me know what you do.

[MonteCitan]

belts can look good and still be bad.. or could have sand/etc stuck in the grooves.. just try replacing the belt and tensioner.. and when you do - make sure the other pulleys are clean/undamaged - $35ish for a belt and $40ish for a tensioner..

I know my regal's chirps if I let off the gas at high boost and low speeds.. (like in first gear)

[232stang01]

the belt may look fine, but may be streached. Apparently, according to the haynes Manual, there is a wera indicator on the tensioner. Try looking tfor that. Replace the belt, then go from there, if you are still having the problem.

[djlarryp]

mine does it, has ever since I bought it. never bothered me.