hi i have a 4lb lower n motoblue idler pulley. i just replaced the belt with a 67in" gatorback belt. im still gettin alittle belt slip at WOT. n it squeaks pretty loud when it shifts at WOT. the squeal is only when it shifts. i have the FTVB so it slams into gear. is there any thing i can do to fix this problem. i tried a 66in" belt but couldnt get it on. i was wondering if my pullies are just old n wooped. the truck has 84,000mi on it. please any help would be greatly appreciated.

 

Check this link out, should help:
http://nationalhorsepower.com/forum/...showtopic=2408

 

thanks for the response. according to that chart my setup would need a 68.5. but i tried a 67.5 before and it slipped extremely bad. is it possible that my tensioner pulley could be going bad. the first time i tried to take the belt off the tensioner was extremely hard to move. then it freed up nicely. then i drove it for a few days until my other belt came in and it did the same thing hard at first then easy. im at a loss. thanks again for the help.

 

Are you sure it's the "blower" belt thats slipping, and not the "accessory" belt?

 

Just my .02 but you might want to try a Gates belt instead of the gatorback. A lot of folks think the gatorback belts are inferior. Good luck man!

 

rob, im pretty sure it is the blower belt because before i replaced it. it slipped very bad. u could feel like a jumping/skipping. it has got alot better since i put on the gatorback belt. i will try replacing the other belt as well. thanks for the advice.

 

Just a thought on the "'accesory belt." I know that in the past some were puzzled by what sounded like a "blower belt slip" - and yet never found any evidence of it (usually some dust on their idlers) and it turned out to be their accessory belt.

Years ago the "Gatorback" style belt was pretty heavily promoted - but in recent years most seem to prefer the Gates belt to minimize slipping because the Gates belt has a solid rib design, in contrast with the Gatorbacks "broken" rib design. The "thinking" being that the Gates solid rib design should offer more "contact surface" at all time with the ribs on the pullies and therefore be less likely to slip.

 

Pretty sure it is the accessory belt. Mine did the same thing and I did every tensioner made for the blower and it still made the squeal on shift, especially the let up shift while accelerating.

No matter how tight the belt is, there will be some give when there is a sudden rpm change.

I ran the Gatorbacks for a couple years until I read that they wear faster and cup the little surfaces.

I checked mine and sure enough, not only cupped, but they stretched as well.

With the Gates green stripe, no such problems.

BTW, You can use the 67.5 from Gates. You may have to pop off the stop tab on the tensioner to get it on, most do, then you should be good as gold.

 

well that woulda been nice to know the other week :P

 

thanks for the responses. i will def try replacing the acc. belt. i just bought this gatorback but if the other one is better than i will have to get it. when my truck is not running the way it should it bothers the crap out of me. my friend has an 04 with just a 4lb pulley, intake, catback exaust and he beat me by a truck in the 1/8. mine is an 01 n i have TB, upper pedulm, intake, bbk headers, true dual flowmaster exaust, 4lb pulley, motoblue belt tensioner, FTVB, oil seperator, boost bypass, and tune. i had it dynoed and it was 381/482. that sound right or my truck beat up. i thought it would put down more but i got let down.lol