Mike,

I installed the Microtuner program in my 2002 SuperCrew. Now at heavy throttle I get a major squeal from the trans when it shifts. It's like it can't handle the harder more positive shift.

Three questions.....
1. will changing the shift pressure help with this problem? If so do I go with a higher or lower shift pressure?

2. does the microtuner set the shift pressure at the max and the stock program at the min?

3. has anyone else reported this?

 

I can't speak for the Supercrew, but on my 97, the Microtuner shift pressure was set very low (if not at it's lowest setting) with the std performance program installation. I bumped mine up a couple notches, and it's perfect, now.

Hard to believe your results! Run the Tuner thru it's paces, using the custom settings and see where it's at. Hopefully, it's different on yours and you and tweak it down a tad.

 

are you sure its not the belt making the noise?

 

I had the same problem. It turned out to be the stock belt squeeling because it cant handle the sudden drop in rpm. Everyone says a Goodyear Gatorback belt will solve it, but I havent changed it yet.

 

The belt?

But it wouldn't make sense....a belt sliping when the RPM's drop.....If it is moving fast and then slows down....would it be sliding ahead....or maybe something attached sliding ahead....or a sudden load on something like the alternator or power steering pump?

Oh well....that's about what it sounds like, so I might as well check.

 

Ya, I thunk it

My theory:
The belt is running off the crank pully right?
And when the rpm suddenly changes, the other pullies are not in sync so you get the squeel from one or more of them.. right?

I hope this is right and its not the trans., but I dont think thats a trans. sound but it is a belt sound....

Now you've got me worried enough to change the damn belt! Thanks

 

Hi bpotter,

Relax my friend, don't worry, your transmission actually isn't making any noise whatsoever because of the Micro Tuner, not one iota, nor is lowering "shift pressure" the answer.

You'll notice the sound really isn't coming from the floorboard at all, which is where where it would have to originate and eminate from if your transmission were actually making that noise. It's coming from the very front of your *engine*, well away from the transmission.

It's your factory ***serpentine belt*** that is slipping, and thus squealing for about a second during a full throttle shift. It's doing that because the transmission is shifting quicker now under full-throttle (not because it shifts "harder," because it shifts *quicker*), so the factory el-cheapo serpentine belt slips on the pulleys, that's all it is, and it's very simple to eliminate forever. All 1997 & up F-150's do that on full-throttle with just about any performance program, because they *all* have lousy serpentine belts, the cheapest Ford can find to make most of them last thru warranty, all the American automakers do that.

All you need to do to get rid of that noise is to put the Goodyear Gatorback serpentine belt on there, and you'll never hear that sound from the vehicle again. Period.

We also carry those Gatorback belts in stock here at Performance(we pioneered them in the F-150 performance community with the help of Goodyear), just give us a call & we can get it right out to you.

Have fun!

 

Ok, I'll belive....but it still doesn't make alot of sense.

I question that any pully has anough momemtum to continue turning faster then the belt for a second or two....or even that all the pullys could turn the belt faster then the crank for that same second or two.

Has anyone taken the time to figure out which pully is slipping?

 

Went through the same thing went I installed my shift kit. At first I thought I was chirping the tires at WOT. Then I started listening closer could definitely tell it was the belt. Actually I was anticipating this based on everything I read and had already ordered the gatorback belt.

Trust me, it WILL fix your problem.

Later.
- Jay

 

It's just a matter of drag on the belt..

 

Its just inertia, the engine pulley is moving the belt and all the other pulleys. At high RPMs when the shift is solid the engine RPMs drop quickly and consequently so does the engine pulley speed because it is bolted directly to the crankshaft. But the belt and other pulleys have built up a lot of momentum in the form of rotating mass and want to continue spinning at the higher RPMs so they drag the belt along the engine pulley at a quicker speed for a short time until they slow down enough to match the engine speed again.

The Goodyear belt holds the pulleys with enough grip to keep all the accesories form dragging the belt over the engine pulley and causing the screeching noise you hear on the 1-2 shift.

Elementary my dear bpotter, elementary.

< LE PEW steps off the soapbox. >

 

GATORBACK!!!