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I have a 2007 E350 5.4L. I was driving at 30-40 mph when I experienced misfires/shuddering. I pulled over and turned the engine off and attempted to restart. Immediately, the sound of starting was different and instead of that sine wave sound where the pitch goes up and down, its a relatively constant pitch. Please see the recording below.
I have checked the battery. fuses, and relays and they seem to be in good working order.
I have since determined the starter does definitely engage and turn the flywheel, and that the serpentine belt and crankshaft pulley do not turn when cranking. Also, the flywheel could be turned by hand force when I removed the starter to examine the flywheel and if it was turning. Also, as can be seen in the video, the tach does not move when cranking. I'm not sure but I guess the crankshaft sensor would control the tachometer?
Forum members from another section think it could be the timing chain or possibly flex plate. Does anyone have any additional insight or advice on how I should proceed? I think I'm pretty much over my head and its going to the mechanic at this point, but maybe I missed something relatively easy.
The flywheel is bolted directly to the crankshaft making the flexplate a non-issue. To me it sounds like the crankshaft broke which is why you can turn the flywheel so easily.
To me, it sounds like the flex plate broke. That is far more common than the crankshaft breaking. There is no flywheel in an automatic transmission vehicle.
I am able to turn the crankshaft with a standard length 1/2 drive handle with normal resistance, so I know my engine isn't completely seized. Oil level was acceptable and not too dark.
Looks like its going to a transmission shop to get an experienced set of eyes on it and see what damage has been done. Thank you for the insight and will provide updates as they come
To me, it sounds like the flex plate broke. That is far more common than the crankshaft breaking. There is no flywheel in an automatic transmission vehicle.
Okay...starter ring gear. Since the starter engages and turns the "flywheel" as the OP said, but the front crankshaft doesn't turn, that would indicate a disconnect between the back and front of the crankshaft since the starter ring gear is bolted directly to the back of the crankshaft. The flexplate is between the starter ring gear and the torque converter, so if the flexplate were the issue the front crankshaft pulley would be turning. Correct?
FWIW, there is an outside chance the center of the starter ring gear sheared off and the starter ring gear is being supported by the TC and flexplate. Meaning, the starter ring gear turns but is no longer attached to the crankshaft. I have seen this happen once in my lifetime.
Since the starter engages and turns the "flywheel" as the OP said, but the front crankshaft doesn't turn, that would indicate a disconnect between the back and front of the crankshaft since the starter ring gear is bolted directly to the back of the crankshaft. The flexplate is between the starter ring gear and the torque converter, so if the flexplate were the issue the front crankshaft pulley would be turning. Correct?
Not correct. The starter ring gear is on the outside diameter of the flex plate. The torque converter bolts to one side of the flex plate and the crankshaft bolts to the other side of the flex plate. It is not unusual for the flex plate to break around the crankshaft bolts. When this happens the starter can turn the ring gear and flex plate, but the crankshaft does not turn.
Originally Posted by alloro
FWIW, there is an outside chance the center of the starter ring gear sheared off and the starter ring gear is being supported by the TC and flexplate. Meaning, the starter ring gear turns but is no longer attached to the crankshaft. I have seen this happen once in my lifetime.
And right there you've described a broken flex plate.
for posterity heres a clip of the flywheel being turned by hand, but I've handed it off to the transmission mechanic and he sounds confident a new flywheel will get me back on the road. was quoted 700.
if this indeed is the reason why I cant start, i wonder what could have caused the damage? I've read the flexplate can "flex" when not secured well and work harden and get brittle, but just seems a little surprising. hopefully i can pop into the shop tomorrow and grab some pictures.
The flexplate flexes by design. As the torque converter spins faster it grows. If the flex plate wasn't there it would push on the crankshaft and destroy the thrust bearings on the crank.
for posterity here's a clip of the flywheel being turned by hand
if this indeed is the reason why I cant start, i wonder what could have caused the damage?
Being able to turn it by hand that easily means it's definitely not moving the crankshaft, there's no way to push through the engine drag and compression that easy. As to how it happened, it could've been metal fatigue that started as a small crack and kept growing, or it could be from high speed wheel spin, such as spinning on sand or ice then grabbing pavement. The one I fixed was due to the wheel spin reason.
received an update from the transmission shop. the transmission bell housing cracked and caused the flexplate/flywheel assembly to not seat properly and engage the rest of the mechanicals. looks like my wallet will be 2200 lighter, but on the birght side ill be back on the road tomorrow. gonna check it out at the shop tomorrow.
thanks everyone for reading and contributing. I just wanted to provide some closure on my e350, and apologies for not posting it sooner. I got it back and put it right to work.
It was definitely the bell housing of the transmission that cracked and everything in it seized up. The transmission shop had bell housings and reman'd innards ready to go, so I just bit the bullet and I was back in business. I possibly could have had just the flywheel part replaced, but with needing it sooner than later, I just had him "drop in" the remanufactured assembly. You can see where it sheared apart on the flexplate.
Gentlemen I’m going to post in shorthand as much as possible , bought this truck made it less than 500 miles and while shifting up while accelerating at a normal pace traveling up a slight grade of an on ramp a commotion of noise came out of nowhere , I think it was 2nd shot dying into 3rd, almost acted like a straight stall out, maintained power steering I think while coating slightly past the white line , stopped , turned key off, counted to thirty tried to start and so began the noise from the above video not a difference i. Sounds, can turn balancer/ lower pulley left or right and complete at least 2 full rotations and also while turning the pulley flywheel ring and torque converter all turn together only when jumping the starter or using the key to attempt start will not seem apply and catch forward of the flywheel , compression feels present, prior to this nothing have any signs of even a possible problem, truck ran wonderful it is 06 5.4 4x4 ext cab , if any tips or ideas that you can offer I’m going to attempt to not spend 2000$ , I haven’t pulled anything yet but changed across this past and needed to share this
09-18-2021, 06:54 PM
Since the starter engages and turns the "flywheel" as the OP said, but the front crankshaft doesn't turn, that would indicate a disconnect between the back and front of the crankshaft since the starter ring gear is bolted directly to the back of the crankshaft. The flexplate is between the starter ring gear and the torque converter, so if the flexplate were the issue the front crankshaft pulley would be turning. Correct?
