a new sound, what could this be?

[DarkFox1]

for the past like.. month my truck has been making a.. wirring sound.. accompanied with some sort of slight vibration at 3k rpm or more.. the whole truck starts feeling tight and stressed.this is almost alwayus accompanied with a hard shift. after the shift it feels like a huge releif on the truck, but does it agian in 2nd. it does this no matter what gear i'm in if it revs this high.

yall know my story about codes and the like.

could this be slipping? whatever is going on.. I think its getting worse.. if its not slipping.. what could it be? tranny fluid is fairly new and is at the correct levels. all maintainence has always been done on time. or very near it.

I'm not going to get it looked at yet.. ford will say its normal.. I want it on the brink of leaving me on the side of the road before someone even looks at it.

 

[jimbo74]

well to me, it sounds like there is some problem with fluid circulation/lack thereof.... but you said its all good.... soooo.... that leaves me guessing too?

 

[DarkFox1]

yea, the tranny was replaced 25k miles ago.. and then I had a busted radiator hose.. and when that happened ford thought it best to flush my tranny fluid, change its filter and do an oil change at the same time... whatever heh, it needed an oil change at the time anyway.

whatever it is.. my dads 86 chevy does it too.. only his s much worse. the truck seems to get more and more resistance as it gets higher in the gear.. so acceleration tends to slow down as rpms go up.. I hope I'm explaining this well enough.

 

[jimbo74]

i'm not sure if your truck has it, but sounds like it could be a detent cable problem.....

 

[DarkFox1]

.. whats that? heh, I dont know anything about trannies.

 

[jimbo74]

i think it has to do with downshifting actually..... but to me, it seems that something mechanical maybe instructing the tranny not to shift when it should..make sense?

 

[DarkFox1]

na, its not like its supposed to be shifting, mean it shifts almost exactly where I'd want it to.. it could downshift alittle sooner I suppose.. but other than that it shifts juts fine.

I know the 4R70W is mostly computer controlled.. it probablly has very litle to mechanically tell it what to do without computer intervention

 

[Robert]

I wonder if your torque converter is slipping? I've seen a few reported cases of the V8's toque converter slipping. Do your RPSs seem to go up but your vehicle speed doesn't seem to go up by an equal amount?

 

[DarkFox1]

well, yea, above 3k rpm its like a waste of time to even stay in the gear, acceleration tends to actually stay the same or slow down alittle as rpms climb. either way it tested normal on a floor dyno. it had 170 peak RWHP at about 4k rpm or so, I think.. can't remember off hand. but thats what the 5.0s supposed to have.. maybe I'm just crazy and pay too much attention to things

it wasn't as bad this morning.. I think its related to the cold.. cos it was really warm this morning.

 

[Robert]

OK, I'm not sure how accurate the HP calculators are but when I punch in 4200 lbs. for my Explorer and me, my trap speed of 83.04 MPH and my 1/4 time of 16.374 seconds, the calculator estimated my rear wheel horsepower at 189.8 & 189.9 depending on whether or not it used speed or time. If the numbers are accurate, then yours is way down from where it should be. This was on my stock '97 SOHC V6.

 

[DarkFox1]

whats this calculator? can it give me an estimate? is it like a url or like.. a program? Alec does't think my dyno results are very accurate, which has me wondering a bit myself, but this guys the only one in town.. so unless I'm up for a road trip, I'd really rather not get another one done for a while

 

[Robert]

I couldn't find the one I originally used but here are some more:

http://www.corral.net/tech/horsepower.html http://www.4racecars.com/calculators/horsepower_calculator.html
http://www.gordon-glasgow.org/hpcalc.html
http://ratsun.com/rpm/hpcalculator.html
Dead Link Removed

 

[DarkFox1]

hrmm.. for a 4500 ponud truck with 215hp.. 16 sec. 1/4..

well unless I get from 60-82 in 4 seconds, I dont think that'd happen.. cos thats the speed it mentions as finishing time.

 

[fordkrazy]

ill put my money on the TC....
i dont think it has a detent cable...i know the v6's dont but not sure about the 5.0
it sounds like the tranny is confused about something.

 

[Robert]

Originally posted by DarkFox1
hrmm.. for a 4500 ponud truck with 215hp.. 16 sec. 1/4..

well unless I get from 60-82 in 4 seconds, I dont think that'd happen.. cos thats the speed it mentions as finishing time.

DarkFox1 - The horsepower you enter is supposed to be rear wheel horsepower, not flywheel horsepower. If you enter the 170 HP you recorded on the dyno it gives you a 1/4 ET of 17.34 @ 78.6 MPH which puts you in OHV territory.

 

[james t]

you can never use rear-wheel dyno #'s to diagnose if you have an engine problem. first things first, your tranny is slipping. if acceleration stays the same, or slows over 3k then its slipping, and thats that.

this is why you cant trust dyno #'s to diagnose daily performance. your tranny could slip 75% of the time, then stop slipping at a high rpm at wide open throttle. in other words, your truck runs like **** most of the time, but when you push it to WOT it eventually stops slipping, showing the peak of 170 rwhp. it doesnt show you the sh!tty numbers you get the rest of the time.

you cant use an equation as a be-all-end-all guage of hp or track time. those are only to give you a close-guesstimate. the numbers will vary alot, you just use it to get a decent idea.

 

[DarkFox1]

well I talked to dave about it last night, if this really is slipping.. then I think thats a solid foundation for investigation into the problem. As soon as I have the $200 or so the shop will charge to open my tranny up, I've decided Ima take it t oa 3rd party tranny shop, leave it so that its cold, and then have them take it out 1st drive of the day and push it hard.. cos I KNOW it will act up then.. I've been there. I try not to push it anymore when its cold cos I need it for now.

what kind of warranty does ford have on their transmissions? I had a warranty when the 1st one was replaced, and I still ahve that warranty, but supposedly the tranny they put in only had a 20k warranty? I'm at 25k on it now..

 

[james t]

with the several experiences you've described before with your ford dealer, i would question whether they even replaced the tranny to begin with.

 

[DarkFox1]

heh, sometimes I wonder that myself. I have a reciept for it tho..

if you want the part #s and all on it I'd be glad to dig it out and show ya.. maybe they didn't replace something they should have.