Go in the shop "lunch is on me to the first person that can tell me what this is"
Buddy dropped the transmission pan on his 86 cougar.found a mushroom shaped piece laying in the pan. Spent a long time trying to figure out where it went.
Hous later he called me.I told him to throw it away. Was a plug used before factory installed dipstick tube.
What im getting at is may have been a cover used in the factory,and was lodged in frame.
I think we've pretty well narrowed it down to the cap breather gasket/diaphragm on the fuel tank cap but you might be partially right. This may have been laying somewhere on the frame all the way from the factory. It may be that someone bobbled it or dropped it during assembly and just left it there so that the parts count on the assembly line would come out right. Or it may have somehow fallen into that area sometime before I bought the tractor and whoever dropped it either couldn't find or couldn't reach it. Either way, it rode there for some time.
The whole situation is a convergence of unlikely coincidences:
1. That it fell off in the first place and apparently without anyone noticing.
1a. OR that it came from the factory this way.
2. That it landed somewhere on the tractor that held it rather than let it fall off and be lost.
3. That a spurt of hydraulic fluid dislodged it enough to fall completely off the tractor but NOT until I had run the tractor for quite a bit longer.
4. That it was laying on the tractor where a spurt of hydraulic fluid COULD dislodge it.
5. That it only fell off when I parked in a place that it could and would be seen.
6. That the circumstances involved in parking the tractor precluded the part coming from any machine other than the tractor.
7. That it didn't go under the mower deck and get shredded unbeknownst to anyone.
8. That even if it didn't get shredded it didn't fall off on a road, pasture or field where it would be just as lost as if it were shredded.
9. That it fell with the concave side up so it was holding hydraulic fluid, which made me think it had been blown off by back pressure.
10. That I happened to look under the tractor as I dismounted after parking so I saw it with fresh clean hydraulic fluid on it -- As opposed to a week or so later when I would maybe not have seen the hydraulic fluid or it would have gotten dirty leaving doubt as to the time frame. This indicated that it had JUST NOW fallen off.
11.That it was discovered after the over pressure/back pressure event that caused the hydraulic dipstick to pop loose and spurt a little hydraulic fluid, and it was discovered with hydraulic fluid on it -- Making me think that it was some sort of unknown cap somewhere that would be affected directly by hydraulic back pressure.
12. There's no way this could have slipped off the cap and gotten itself under the cowling and sheet metal. There's no gap or crack big enough for this to fit through to get in there and especially not unnoticed. Whatever caused it to end up where it was on the tractor until it finally fell off where I parked it ... wasn't some "normal" slip and slide to where it must have lain until it fell down on the ground. Which takes us full circle back to 1a above.
