Strange sound.. a missing torque converter nut?

[69ARROWHEAD]

As I went out to take my family out to breakfast this Sunday morning, I was greeted at startup with a horrible clattering sound.

It was sheer panic for me! I immediately checked my oil pressure. Turned off the engine and checked my oil level and was only slightly low.

Well, I took the family in my F-250 and suffice it to say I did not have a good breakfast with this horrible clattering sound on our Explorer on my mind.

As soon as I got back I changed into my work clothes and tried my hand at diagnosing. The sound was defiantly coming from deep down inside.

I had to pinpoint the noise so I thought I would attempt to separate the torque converter from the flywheel to make certain it was an engine noise. Well, low and behold I removed the starter to get at the TC bolts and upon rotating the flywheel by hand I found that one TC nut was MISSING! Could this be the source of all the racket?

I spent the better part of the afternoon with every magnet, coat hanger wire, and inspection mirror trying to find this nut. NO LUCK! I have all the transmission bell housing bolts removed and loosened the trans mount bolts to see if I could separate the trans just enough peek inside. NO LUCK!

I will probably have to remove the cooler lines and maybe the drive shaft to help nudge the trans.

Anyone have any suggestions on how to find this loose nut? By the way, While trying to rotate the engine by hand, I come to a point where engine binds up and gets stuck. It is 1 complete revolution then stuck. (the missing nut?)

Alfred

 

[E.B. Cornburner]

On Fords, typically, removing the starter gains you access to the convertor nuts/bolts. You might be able to fish a magnet down into the bellhousing to try and retrieve it that way.

 

[69ARROWHEAD]

Hi Mike, This is where I was trying to fish the missing nut. I just couldn't find or feel anything. Very frustrating. This is why I attempted to loosen the bell housing bolts.
I would assume it is in front of the flywheel?

Alfred

 

[E.B. Cornburner]

In theory it should be, since the studs go thru the flexplate from the convertor, but I've seen them lots of times just fall to the lowest point in the bellhousing too. The convertor is smaller than the flexplate, so it's a crapshoot to know if it actually stayed in front of it. Otherwise, centrifugal force could have lodged it somewhere else, and who really knows where that would be until it was found.

Here's something that might help...On our race car when we have to change a convertor, flexplate, etc. we've made some studs that will allow the tranny to slide back about 5" or so but not come completely out. Just remove the driveshaft and slide it back, do your job, and slide it forward again. You'll have to remove the rest of the covertor nuts first, otherwise, the convertor will stay attatched and pull out of the tranny pump, and then that's a PITA to get lined up again.

If you have some cylinder head bolts laying around, sometimes these are long enough to act as alignment studs for this purpose. I believe Ford uses M10 bellhousing bolts, which is a common size head bolt on most modern engines such as a Chevy 3.1, Chrysler 2.2, etc.

 

[BlueExpy]

Quick thought?

Not trying to be a smart a$$, but are you sure the flywheel is missing a nut? There is usually a hole left for draining the torgue converter. I only say this cause I am hoping that maybe your problem is a bendix in the starter. It's what allows the starter gear to retract. I've had that problem before and it's an awful squelch, squeal, sqwack, grind noise.

 

[69ARROWHEAD]

Blue,

I am sure it is a torque converter nut. I removed three and the last torque converter stud was missing the nut. I could see the shiny spot where the nut once was.
Plus the service manual specifically states there are 4 (four) I only removed three.

I know I wont have a good night sleep tonight with this on my mind.

Alfred

 

[E.B. Cornburner]

I haven't seen too many domestic trannies with a torque convertor drainplug. Lots of the European and some Japanese trannies do have a drain though...Great idea, but that would make the tranny last too long, and we all know the domestic manufacturers wouldn't want that to happen.

 

[BlueExpy]

My 89 F-150 with a C-6 had that drain plug with a matching hole in the flywheel. I don't know about the newer fords, but I'm not going to pull my 07 apart to find out.