I have a 2007 f150 with the 5.4 V8, automatic, 4x4 and about 83,000 miles. We've only had the truck a few months and it has run and driven perfectly, no complaints. I went out to move it up on our driveway from where my son had moved it earlier in the day (without incident) and the starter sounded as though it was engaged and turning but the engine was not turning. I tried several times and finally got the engine to start but with a lot of clanging noise (like nuts and bolts loose in the bell housing or something) so I shut it off. Haven't been able to start it since but the starter is still engaging and turning at the normal rpm. I got under it a few days later and looking into the view hole in the bottom of the bell housing confirmed that the starter engages, the flexplate turns but the engine is not turning. My questions are: could the flexplate really have become disconnected from the engine or is there another explanation? And, has anyone else experienced anything like this? Thanks.

 

At first I would say that your starter is going out, the bendix could be spinning without kicking out to engage the flywheel. However, if you made sure the flywheel is spinning then that can't be it although I would still bench test the starter just to make sure. I think autozone does this for free. If the flywheel is spinning without turning the engine over then you have problems, although I can't imagine the bolts would all just fall out. Plus they would have to be in the bell housing somewhere. I would check the starter first, hope this helps.

 

the bolts should not have fallen out of the flexplate, but that would be the best bet for this scenario. it sounds like major problems.

 

Thanks for the quick response. I agree that it seems very unlikely that the bolts would just fall out. At this point, I don't know or actually, I'm afraid to think of what else might be going on. I'm thinking a removal of the trans may be coming up in the next weekend or two just to see what the problem actually is. I'll pull the starter and check it first, just to make sure. Any experience pulling a trans in one of these? Anything out of the ordinary I should watch out for or avoid? Thanks again.

 

Sounds like a broken flywheel/flexplate, I would try turning the engine by hand with a breaker bar on the balancer. Being a 4x4 the trans is a little tuffer to get out

 

Thanks. I should have mentioned that we did turn the engine over, by hand just to make sure it hadn't locked up or something. It did turn with an appropriate amount of resistance. That's what's got me wondering; with the starter on, the flexplate is not only spinning but is spinning true, as thought it is still stablized by something. Maybe the bolts have sheared or somehow come out and it (the flexplate) is spinning on the end of the crank?

 

Can you put a pry bar in the access port to turn the flywheel to see if the engine turns? Turning at the damper is great to check for engine freeze, but you are describing a disconnect at the crank shaft and flywheel. You might want to understand the issues a little more before dropping the trans.

 

I agree with craftsmangary. Your flexplate has broken off by the sounds of things. For what it's worth, I had a truck a few years back that the starter would spin free when engaged that ended up the flexplate was broken off almost perfectly flush to the flange portion that bolts up to the crank. This sounds like what you've experienced. Does this truck have any harsh transmission shifts or issues with harsh engagements? Has it been shock loaded at any point in time. And yes, I agree if it's a 4x4, it is a pretty involved job pulling the transmission, but at this point, I don't think you have any other option.

 

Thanks again. EBTDM, I have not yet tried a pry bar in the access port to turn the flexplate, I've only spun it with the starter but will give that a try and see if the engine turns. Thanks for the suggestion. Question, if the engine does turn by turning the flexplate through the access port, what might be wrong? If the engine doesn't turn, same question?

 

If a pry bar turns the flexplate and the engine in the access port and the starter won't turn the flexplate and theengine, it would be just pure luck.

The flexplate maybe turning "true" because it is still bolted to the torque converter.

You might find out more by pulling the starter, get a flashlight and a mirror to see if you can see something more.

The clanging noises sounds like that:

1.There is something lose in there. (bolts)

2. The broken piece on the crank is hitting the broken flexplate on the torque converter when the flexplate rotates around the broken piece on the crank.

3. Both.

4. Something else.

I feel fer ya man.

 

I have to say, I'm very pleased with the response from everyone to my dilema. I registered reluctantly, not sure how long if ever, I'd get a response. Thanks so much! I'll take your advice and see what I can see through the starter hole and keep you posted. Thanks again.

 

The end result is is going to be the transmission needs to be pulled, no matter what you find. Without seeing it, and the way you describe it, it needs a new flexplate, plain and simple.

 

Turning the engine by turning the flywheel tells you simply that the flywheel is still bolted to the crankshaft. (The transmission connection to the flywheel is nice to know but not relevant to the symptom.)

If the engine turns then the starter is at the center of the question. The starter gear is held to the starter shaft by a roll pin, keyway or both, and engaging by a bendix spring to the flywheel. These have been known to shear. That is why in they have also been often referred to as shear pins. Also the teeth on the gear and/or the flywheel will also shear off, usually from a misaligned engagement between the flywheel and the starter. These are more common to the symptoms you describe.

If the engine does not turn then the flywheel is no longer connected to the crankshaft. I have only seen this on racing drivetrains but it does happen.

 

Enough said.

 

Thanks again for all the input. My son and I are slowly moving forward with the transmission removal. He's working on getting the starter out first, while I'm at work, at which time we'll assess the situation and make sure the tranny does need to come out, which I'm expecting. You all have been great! I'll keep you posted. By the way, if anyone thinks of anything to do or not do or watch out for while removing the trans, please feel free to comment. Thanks.