WHIRRRR?

[Tbird9140]

If its not one thing its another.  With the help of you guys finally got the obvious issues resolved with my white beast.  Now however about a week ago the truck started producing a new quite loud sound when I let up on the accelerator.  Hard to reproduce in letters but sort of a "whirrr" or "rurrr" noise that starts the moment I take my foot off of the fuel pedal and continues until the rpms drop.  The harder I am accelerating when I release the pedal, the louder it is.  I do not hear it when I am accelerating but at that time the exhaust noise may be covering up the sound.  I don't notice any driving issues (truck seems to be running normally) and no check engine light, so can't report any consequences of the noise.  The noise starts up loud and trails off as truck coasts slower, ceasing when the rpms bottom out.  Can't really say if it is coming from 5.9 or 47RE.  Don't want to be driving the truck if this is the sign of a bigger problem as I have had to already replace one VP44.  Any thoughts or suggestions?  Any tests or checks I should undertake of the engine or tranny to diagnose my issue.  It is a bit unnerving to drive in the city and hear this noise every time between traffic lights.  Thanks again for any help.

[Threadzy]

Here’s a dumb question. By chance is there an exhaust brake on the truck? 

Edited August 27, 2021 by JAG1

[IBMobile]

What happens if you put it in neutral when coasting to a stop? 

[JAG1]

If it sounds like you are driving on slightly knobby tires it's most likely wheel bearings. On my 01 it was like that for six weeks. When I'd check for play there was none. Only when I spun the hub with my hand, wheels off, could you tell it was a rough bearing . Finding out that that was a sure way to tell, I checked the other side and sure enough it was bad too. I changed both bearings that weekend. I got them off only by pure persistent ideas and attempts. I had to learn a few tricks. I thought at 69 there are no more to be had.

Edited August 27, 2021 by JAG1

[MikeH]

1 hour ago, JAG1 said:

I changed both bearings that weekend. I got them off only by pure persistent ideas and attempts.

I chickened out on my front bearings. I did the rears but after hearing some horror stories on getting the front hub/bearing out I let the shop do it. I asked the guys at the shop if they had any trouble getting them out and he said "Nope, popped right out with a few taps of a rubber mallet". Oh well...

[JAG1]

3 hours ago, MikeH said:

I chickened out on my front bearings. I did the rears but after hearing some horror stories on getting the front hub/bearing out I let the shop do it. I asked the guys at the shop if they had any trouble getting them out and he said "Nope, popped right out with a few taps of a rubber mallet". Oh well...

Mine wouldn't come out with a chisel wedged in there and air hammer. Everyone thought I was running a machine gun trying. I had to  cut/ grind the bolt flange thinner so I could bend and (PEEL them off). Finally I saw a little tiny bit of movement. That was a good moment and had them off not too long after. I coated all the mating surface with anti seize on the new hub bearings.. 

Edited August 27, 2021 by JAG1

[wil440]

Hasn't the trans got a overrun clutch ?

[MikeH]

12 hours ago, JAG1 said:

Mine wouldn't come out with a chisel wedged in there and air hammer.

I've seen torches, air tools, sledge hammers, pry bars, special tools, etc used to get the bearings out. Had none of that stuff so turned it over to my local shop. After 20 years I just assumed they would be a fight but apparently they came right out. 

[Mopar1973Man]

I've done a front bearing a in a friends shop in down in south Idaho. I didn't have access to all the materials I needed. I typically anti-seize everything. Needless to say after one winter and having to pull that bearing again to do wheel joints it was about a 2 hour beating session with a 6 pound hammer to get it out. Anti-seize is a good friend of mine. 

 

Typically they come out really easy. Just don't leave anything metal on metal or you'll fight to get it out. I also do use a hone brush to clean up the bearing holes good and clean. All it takes is one winter with road salts and you'll be fighting. 

[JAG1]

2 hours ago, MikeH said:

I've seen torches, air tools, sledge hammers, pry bars, special tools, etc used to get the bearings out. Had none of that stuff so turned it over to my local shop. After 20 years I just assumed they would be a fight but apparently they came right out. 

Lucky deal! My drivers side took awhile. Backing out the bolts a quarter inch and using the air hammer did not phase it. It mushroomed the bolt heads, couldn't get the socket  back on. Had to file off the mushed out bolt head. The best is to use a grinder to make the steel thinner next to the mate surface so when you put a wedge/ chisel to it will peel/ bend away enough that it will hold the chisel for you to get a good hit with both hands on the mini sledge. Do that to both side and you will loosen it.

Edited August 28, 2021 by JAG1

[Tbird9140]

Lots of replies about wheel bearings.  Don't think that is my problem.  Went to a steep hill, put it in neutral and coasted down hill, and no noise what so ever.  Then drove back up hill accelerating - then took foot off pedal, got noise until rpms dropped.  Checked exhaust don't hear or see any leak.  Started truck and left in park.  Revved it up to 3000 rpm and then quickly took foot off accelerator.  I could hear the noise but interestingly, not nearly as loud as when driving down road and did same thing.  I don't have knobby tires, use truck exclusively for towing cars on highways.  This started up about two weeks ago and I have not messed with tires, exhaust, or anything that I can think of around or shortly before that time.  Did put a set of A column gauges (fuel pressure, exhaust temp, and boost) about a month ago.  Not sure this is related but driving down flat highways at 45 mph my boost shows practically nothing (maybe 2 lbs.)  When I accelerate from a start at a stop light with no load maybe the gauge goes to 6 lbs.  Pulling trailer and full sized car at 55 mph up long incline, never have seen more than about 16 lbs.  As far as I know (bought truck used) I am running stock turbo and injectors.  Do these numbers seem correct for a truck with 335,000 miles, uses no oil and has no known driving issues.  Could I be losing my turbo resulting in the noise?  I am pretty sure that the noise is engine or tranny related, it just doesn't sound like anything else, especially as I don't get it except when I am decelerating.  Thanks guys for at least trying to diagnose my problem.

Sorry, forgot to mention.  No exhaust brake.  Can't get noise with any amount of "coasting"  Only loud and persistent when driving and let up on accelerator.  Like decelerating for a stop light or slowing down while  accelerating when an idiot pulls out in front of me. at 25 mph.  My truck is normally pretty loud from exhaust noise so I guess it could be there when I am accelerating.  But I don't think so.  When I take my foot off accelerator on every occasion,  I hear noise.  The harder I was accelerating (higher rpms) the louder the noise.  I may need to drive the truck again to the West Coast soon to pick up an old TBird (I restore them) and don't want to start out with a "ticking time bomb".  Regards All.

[Mopar1973Man]

Check your turbo?

 

 

[IBMobile]

30 minutes ago, Tbird9140 said:

Do these numbers seem correct

On a stock turbo set up the top boost pressure looks a little low; should be 18-20psi.  Over 20psi and the ECM defuels the engine unless there is a "boost fooler" installed. 

Easy to check the turbo for play.  Usually a turbos with excessive radial play (side to side) makes noise accelerating when drive pressure is high.  

Second thought is a bearing in the transmission.  When coasting in neutral torque loading on internal parts is reduced.

[JAG1]

I"m thinking the carrier bearing or U joints on the driveline(s). Also differentials oil levels but, I am tossing this out there for something should be checked periodically anyhow.

[MikeH]

6 hours ago, Mopar1973Man said:

Check your turbo?

I was just going there. Those boost numbers are way to low especially under load. Check the turbo as MoparMan suggested for axial and radial play. You would think if it's a boost leak the noise would be worse while accelerating but I would still have a look at all the connectors, elbows, clamps etc from turbo to intake plenum. 

Another thing that came to mind was the harmonic balancer. I really don't know the symptoms of a bad balancer so maybe someone came chime in if this is a possibility.

[JAG1]

1 minute ago, MikeH said:

I was just going there. Those boost numbers are way to low especially under load. Check the turbo as MoparMan suggested for axial and radial play. You would think if it's a boost leak the noise would be worse while accelerating but I would still have a look at all the connectors, elbows, clamps etc from turbo to intake plenum. 

Another thing that came to mind was the harmonic balancer. I really don't know the symptoms of a bad balancer so maybe someone came chime in if this is a possibility.

I had to put a new Harmonic balancer on mine. You could see where the oil from a long overflowing breather bottle (PO) had deteriorated the rubber isolator ring in the balancer and it wobbled more than an 1/8th of an inch at idle. The new one from Cummins smoothed the engine nicely, but, it wasn't anything you could notice while running down the road only when stopped at idle. My plumber got in and we stopped at a light and goes,'' Dang this thing is smooth''. After a nice dose of 2 stroke and new balancer it sounded, still is, really good. 

[MikeH]

4 minutes ago, JAG1 said:

it wasn't anything you could notice while running down the road

OK...It was just a thought on the balancer. Turbo numbers however do look low to me.

[JAG1]

1 hour ago, MikeH said:

OK...It was just a thought on the balancer. Turbo numbers however do look low to me.

Take good look at all the intake /boots hoses, everything, particularly down low in front of drivers battery. There is a spot you can see from underneath where part of the fender (sharp edge) gets real close to the boot down there. On some trucks it been found touching or rubbing. I think some boot leaks are like an innertube hard to see unless you know where the damage is. 

 

Anyhow I took pliers and bent the fender back out of the way on both my 2nd gens.

[Mopar1973Man]

4 hours ago, MikeH said:

OK...It was just a thought on the balancer. Turbo numbers however do look low to me.

 

On the damper there is two tick marks in the damper if it lined up and not wobbling then your fine. Since I did a crankcase vent mod I've never had a damper issue being no oil gets down there. 

[JAG1]

Also no deteriorated distorted rubber mushed or sticking out. 

Edited August 29, 2021 by JAG1