I just want to see if anyone else is having the same issues. My 01' 5.4 off road had to go into service around 14000 miles due to a blown converter.(from a dead stop I woould rev freely, gradually accelerating to about 25-30mph).

Well, Now I'm at about 16500 miles and I'm noticing that under hard acceleration, when the trans shifts from 1st to 2nd (i think) I hear a whine (like when a fan belt is slipping) and there is no kick at all, it almost feels as though I let off the throttle for a brief second.

Has anyone had similar issues, or suggestions????

Later

 

i think the noise you are hearing is normal. my '01 s-crew with 4r70w made that noise on full throttle upshifts. i haven't noticed this on my new '02. but i also haven't done any full throttle upshifts with it yet either...

 

You are probably hearing the serpentine belt slipping. It's a common problem that's been posted here many times. The factory belt is durable, but has poor grip. The fix=Goodyear "Gatorback" #4080990 from Autozone for $29. The slop shift is normal; slip, overlap, and electronic management do this. To remove it you get a shift kit and a Superchip.

 

I agree with Max that it is the belt slipping. I had the exact same very loud squealing with a WOT upshift, but since I went with the GY Gatorback it is totally gone. BTW I thought the Torque converter in these trucks locked in 2nd gear? Maybe I am wrong though... Wouldn't be a first!

 

i'm not sure why the belt would hold off on sqealing until exactly at the point the tranny upshifts, but whatever.

i believe almost all automatics only experience tc lockup after say 40 mph...sooner than that and you'd probably have driveability problems...

 

The belt will hold off slipping until just when the transmission shifts. Here's why.

When the transmission shifts the engine speed drops rapidly. If it drops too fast the crankshaft pully slows down faster than the belt driven accessories. This causes the belt to slip on one or more of the pulleys.

If you put a shift kit in that makes the transmission shift faster it will slip the belt even more.

Mark

 

Hmmm. Perhaps you're on to something.

On a few animated occations, I've heard what I thought was tire slippage during the WOT shift from 1-2. Now, I WANTED to believe that it was the tires -- since I can get my Goldwing to do it (grin).

Since I've heard it on different road surfaces (this morning yet another), I discounted the "tire spin from powerful behemoth" theory -- and reverted to the "oh, gee -- I hope I'm not hearing the tranny clutches" mode.

What I hear Does fit the centrifugal force belt slip theory presented above -- and I'd much rather Believe it -- than the tranny-clutch/band theory that I dreamt up.

Thanks for posting.