Ford 6.7L Power Stroke Diesel :: Loud Clunk / Bang When Downshifting Under Load
May 15, 2016
38k and 15 months old. Runs fine except...
Can be in cruise or not, tow/haul or not, but need to be pulling a decent hill with 7k+ trailer. Running level with air bags. Regardless of speed, cruising at 50, 58, or 65, beginning incline and turbo boost builds normally to maintain speed to the point when it needs to downshift. BAM!!, not just a clunk, 90% of the time- scares the hell out of me. I can make it do it on an incline empty, but it it difficult. If because initial speed is 50ish, a second downshift to 4th may be needed. A bang only 50% of the time.
No codes.
Regardless of the degree incline, (toughest in the NC/KY areas is 6-7% grade, can avoid harsh shift by backing off on throttle and manually downshifting to 5th or 4th, depending upon speed.
Can "make" it do it on level terrain with 7k trailer if I slowly back off throttle and slow from 65 to 50 or so and punch it, but not too hard. Too hard and it goes to 4th, usually with just a modest clunk. Just right and I get 5th with a loud, and I mean loud BAM. Even the tech was impressed.
Afraid to hook up my 17k 5er and take off for the next 3 months, which is the reason I bought the truck to replace my 11...
Carrier bearing has grease coming out of it (400k on various duallies and never seen this), but dealer says not an issue.
Ford told dealer that it had no idea, and advised tech to do a lot of pin point electrical testing and everything checks out. Next stop is the inner workings of transmission.
I have been without it and work for 3 days because of backlog. Running two day load tomorrow, then back in for tranny work.
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So I have just over 14k on my 2015....... I love the truck but have had a few small issues. I had a water leak coming in from the roof that would leak through the grab handle. Nothing major dealer replaced one clearance light seal and they said the windshield needs to be re sealed.
Then I had a god awful irritating squeak in the dash..... It only does it late In the day when it's been hot. The dealer said it was a loose air bag. I have had the truck back a week and it's doing it again.
Those are little issues that will get resolved...... I hate having problems with a brand new vehicle but I understand it happens and that's what warranty is for.
I also reported a bad shake to the dealer...... The truck will shake very violently and have a very loud "diesel" sound. It's very specific at when it occurs. It has only done 4 times in the past 6 weeks including today. The odd thing is the 4 times it has done it has been the same time of day in the exact same spot on the exact same road!!!!
Basically I leave my office sit in some traffic and by the time I get to the parkway it has been35 minutes or so. Only happens in 6th at 60 which is roughly 1,400rpm a slight load due to a small incline and it shakes real bad! The typical "diesel" sound you get when under a load is very pronounced almost to a knock. It will continue to do this as you slowly increase throttle until it down shifts and then goes away. I also caught it doing it and I manually shifted to 5th and it went away.
Because of the rpm at which it happens with slight load only doing it in 6th I lean to a Trans issue and more so a converter problem. It feels like converter shutter. I just don't understand the engine sound.
I gave very descriptive info to the dealer..... Several techs drove it and could not duplicate. I just picked the truck back up last Thursday and the dash squeak is back and the shake happened yesterday and again today. So I am a bit irritated to say the least.
I really hate the fact that I know there is a problem but I also understand if a tech can't duplicate it he can't diagnose it. However today I did get a video of it with my phone so they will know I'm not making this crap up!
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So I took the wife to the pumpkin farm today, and was we were pulling into the grass/mud parking lot, my tires just started spinning. I stopped because I wasn't going anywhere and I turned my truck to go into 4x4(SOTF) and it made this LOUD clunk and then went into 4x4. Everything is ok and I tried it 4-5 after that to see if it would keep making that noise and it did not.
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Last year I did some major work on my 02. Painted it, new injectors, 38R, and once it was back together, the transmission went south in a month. Got a Ford reman HD4R100. Shortly after the install, when in reverse, the torque convertor would lock up when you stepped on the throttle. As soon as you let off the throttle, it would disengage. Thinking it was a tranny issue, got another one from Ford. This one has been in the truck for about 9 months. And it seemed fine until about a month ago. It started doing the torque convertor lockup thing in reverse like the last one, but not as often.
Then last weekend it did it every time I put it in reverse. Then yesterday, while pulling away from a traffic light, there was a loud bang, and lost power in the transmission. Once stopped, I found out it has manual 1st and 2nd, but nothing else. No drive, overdrive, or reverse. I personally believe something electrical led to these issues, and ultimately, the transmission failure. I know the truck is not stock, but I do not run it hard very much. When it went bang yesterday, I was not being hard on it. Where to look at what is causing this?
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2005 V8 Phaeton,82,000 miles.
If I ease on the brakes ,no problem but if I hit the pedal there is a loud bang or clunk from underneath,sometimes front and sometimes in the back. It's as if the wheels stopped but the chassis went forward and back slightly. As long as I put the brakes on gradually there is no problem stopping.
When I come off the Interstate and leave the off ramp, the low side of the front end sounds as if there is no shock absorber ,doesn't matter which side is low,they both do it on the low side.
Intermittent problems.
Steering wheel turns and grinding,groaning noises from under the hood, not all the time.
Going over a speed bump in a parking lot causes the same noise I get exiting the Interstate.
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While driving I went to speed up and heard a bang. I lost all drive. I have no movement in any gear. I got the truck home and looked around. Trans fluid looked and smelled ok. I couldn't move the rear drive shaft by hand with engine in neutral. I drained the transfer case and that fluid looked fine also. What it could be or what else to look for. The truck is a 2006 f350 with 6.0 and 185,000 miles. Up to this point I had no trans issues.
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Got a 2011 F350 Crew LB. When I'm pulling a mild grade, put my foot in it and down shift at about 60mph, I will get a real good rear-end bounce going on. It sounds real similar to the 45-50mph bounce in that if I slow down or power through it the bounce will go away. If I sit there at around 55-62 it will develop a real good hop (standing wave like). I've never had the 45-50mph bounce problem, BTW.
It just started happening in the past few months. The truck has an Icon leveling kit with bilstien shocks and slightly taller tires. The leveling kit and tires have been on there for a couple of years. Just replaced a leaking rear shock thinking it was the cause, but no happiness.
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I tow a car hauler that is about 8000 lbs. On my last trip occasionally when the truck would downshift into 5th under a load, it would bang in there pretty hard. Not a smooth transition, not every time just some times. Just wondering it that was normal or the start of a potential issue.
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First off I have a 2001 7.3 with 294000 miles. While pulling my camper after it gets warm it puts out a very loud whistle it seems to happen when the fan clutch kicks in it does not sound like a belt squeal it almost sounds like it's coming from the turbo area. The engine seems to Surge while this is going on but the RPM gauge doesn't dictate that it almost sounds like it's the fan clutch surging. I took a short video of it while it was doing it ...
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I just noticed I could manually down shift transmission in D drive by tapping - on shift lever. I thought this was only possible in M manual mode.
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I have a 2006 F350 Superduty hd 4x4 6.0 Diesel. When it begins to start pulling from a standstill, it will not build power to untrack the load. Once it gets going the turbo will build boost and pull fine. Checked Boots on tube from turbo to intercooler for possible leaks. Replaced tube from intercooler to intake. Made sure map sensor tube was clear of soot (none at all in there). Air Cleaner is in good shape. Im a little Frustrated.
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I posted earlier about a whistle that appeared when I was towing my old travel trailer (6000 pounds). It only happened a couple of times, and I had a hard time replicating it, so I elected not to waste any money with the deductable, and possible additional costs for a non-covered issue at the stealership.
Now, I am towing a larger 5th wheel trailer (11000 pounds), and am experiencing this whistle on every steep grade, while towing. Below are a couple of things I noticed, that had to be, before I would get the whistle:
* It only seems to happen while the cooling fan is engaged, and also only when the rpms reached 2800 and above.
*If the fan was on, but the rpms were turning below 2800 rpms, then it would not whistle. It would, however, after the transmission downshifts, bringing the rpms back up, while climbing.
*If the engine was spinning at 2800 rpms, and the engine fan was not engaged, then it would not whistle, until the fan would kick in.
* It only seems to occur when I am climbing a steep grade, on a warm day. Although, I haven't experimented on steep grades on a cold day...
It sounds to me like there is an issue with the engine fan system, but I thought I would put it out there, just in case any of the diesel guru's out there might know of something else that would cause a whistle like this, i.e., turbo?
Oh by the way, I also think that I have a performance reduction lately. However, I can't know for sure, as I have never towed this much weight with my truck before. I just kind of expected that I would be able to pull to the top of these grades, with a little extra peddle to spare. I have to floor it, just to "try" and keep up with traffic. And I haven't calculated my fuel mileage while towing this beast yet, but WOW, that fuel gauge needle sure does drop like a rock!
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My 6.0 stalls out when under load above idle intermittently. When it stalls, if I release the gas pedal and tap it, it usually catches again but not always. ICP is strong and doesn't seem to waiver when it stalls. Engine runs much better when oil comes up to about 180. Oil / water temp spread about 5 degrees.
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After replacing both heads with remanufactured heads from ford along with new egr and oil cooler a month ago, she still overheats when pulling a load. While normal driving and not towing, no problems. In the last 5,000 miles since work was done and while towing approx. 15,000 lbs (load and trailer weight) she got hot once, slowed down, temp retreated got home - she has not overheated since then pulling 4-5 loads over the next 2,500 miles. Today at about 75 degrees only 4 blocks after picking up a load at about 12,000 lbs she started getting hot again. After I let her cool down and got on the Freeway the temp went down, appears she's not staying cool in the city with a load on. With all the work and new parts I had installed, what the problem might be?
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I ran about 500 miles today loaded up pretty good and noticed every bump I hit that was enough to rock the truck and trailer that there was a noise I've never heard before. It was like the difference between asphalt and concrete road surfaces, but was only present when the springs were sufficiently compressed. Temps were between -10 when I left to 10 or so above when I was destinated. Would that cause the noise?
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I have a 2003 f 350 6.0, when under a heavy laod such as towing a 3000-pound trailer up a long hill at approx 60mph and 2000 rpm it intermittently mis fires.The boost gauge bounces up and down and i here a poping sound from the engine compartment.I have had it to several dealer and independent shops but with out the trailer or a heavy load it runs perfectly.They have told me fuel pressure is good and changed all fuel filters with OEM parts.
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2005 F250, 6.0, 60K miles, recently (within last 1K miles) had ARP studs, EGR delete and new oil cooler installed. Shortly after (5-6 weeks later) I noticed blue smoke under any load (taking off from red light, backing up) but not at idle or startup. Was using the "Performance" SCT canned tune after the stud install, but had the "65HP Tow" canned tune installed when I first noticed the smoke and now back to stock after noticed the smoke as a precaution. Everything else original except FICM, filters and batteries and use 5w40 Mobil 1 since new.
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So pulling my trailer and 4x4 and the truck dies without any other symptoms. No check engine light all other electrical remains working. This happened 6 times this trip always while pulling a grade but only after the truck has been running for a few hours. Each time, no warning and once the truck has set for 5 to 10 minutes it start up like normal. The longer i let it set the longer I can run before it does it again. ICP is 550ish at idle, 200ish while cranking. Check the FICM before the trip and it was at 47.5 to 48.5v key on engine off and running. STC, stand pipes, dummy plugs, ball cups have all been done.
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While i am pulling a loaded trailer we have been experiencing a random Chug that only last about 1 second we have no lose of power during when it happens. We Recently just replaced all fuel Filters. We have an updated EGR on it with a cold air intake and muffler delete. It has about 180000 miles on it it runs awesome and starts right up just trying to figure what this problem could be..
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In the last 3 weeks I've replaced the oil cooler. IPR, ICP, fan clutch, intercooler, rebuilt the turbo, new elc coolant, egr valve, thermostat, new batteries, positive battery cable, and alternator and a host of other crap. Now I have a new problem.
When towing it overheats, almost instantly under load. I was towing a 9k trailer up a hill, a total of about a 30 second climb and it overheated (242 degrees). I'm thinking head gaskets at this point as they are stock and have the tty bolts installed.
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Recently had a rear pinion leak and replaced the seal and nut. I jacked up the truck, took off wheels and felt the drag so I could duplicate once i had the new seal as I tightened the nut. I've done this only once before on my F150 years ago, but when I put the driveshaft back on and test drove it, i had shudder when not under load. So when I let off of the accelerator, it had shudder and more the faster I was going.
Obviously thinking this is a preload issue with the rear axle but would this be caused by tightening too much or too little. I had no issues before so I would think that the driveshaft itself is not the issue. I can't confirm that I got it bolted up in the exact same manner as before in relation to the flanges but still wouldn't think that to be the issue.
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