So I need to get a C6 rebuild kit rather than just the o-ring, correct?

 

Or is there a way to fix that without spending $250 if it is leaking?

 

No you just need the O-ring for the kick down lever for now. Do that first.
I'm pretty sure that will stop the leaking.

 

Where is this O-Ring ? Not on My C6, behind the NSS. The valve body had to come down.

 

I replaced the o ring. The old one did not look to bad, but seemed not to be seated. I pressed the new one back in there as good as I could. When reassembling I saw that there is nothing pressing tightly against this o-ring to keep it seated. I assume this is the way it is supposed to be, but was not sure. Assembly went o ring, bracket arm (which lays flat against the stud, but does not press against the o ring because it is deeper in there), NSS, lock washer, nut. The nut was stripped from over tightening (not from me) and would not tighten enough to flatten the lock washer so I have to go find another one at the hardware store.

I replaced 4 of the transmission pan bolts, two of which were missing and the other two were to short to tighten. Other bolts on the pan were also lose. I think that is where most of the leaking was coming from ( I guess I should have checked that first). It was definitely leaking from behind the o ring as well, but hopefully that has stopped. I will not know until I drive it which cannot be done until I replace the nut.

 

I also have a pic of it which I will try to upload later.

 

I had my assembly mixed up in my last post but this the pic of the NSS with the lockdown bracket in front and the o ring installed.

 

I went to Home Depot to find a nut for the transmission and tried the nut on all of their sizing bolts and it fit none of them. What size is this nut? Is it something special? It seemed to start on both of the 5/16 sizes, but stopped after about 1 or 2 turns.

 

I'm pretty sure it is 5/16" NF

 

OK thanks. I guess that must be something I have to order online.

 

Are the threads on the stud clean? Meaning, are they sharp and defined? A burr or burrs in the thread can stop a nut when trying to hand tighten it.
A thread pitch gauge would help here. AP stores as well as Harbor Freight have them cheap enough. I think you are going off of it being a 5/16's hex wrench size and maybe not the actual stud size. I could be wrong though.

 

The threads on the stud are pretty clean. The problem is that the nut is almost smooth inside from the threads ripping out (I assume from somebody over tightening?). The reason I thing it is 5/16 is at the nut starts on a 5/16 screw better than any other size. It still screws onto the transmission stud, but it will not tighten enough to flatten the lock washer.

Will NF always be 5/16x24?

 

Before ordering on-line, i would take the nut to a parts store or dealer for a possible match up. Let them know what you are working on.

 

Look at this:
https://en.wikipedia.org/wiki/Unified_Thread_Standard

 

The fact that the nut threads are stripped out is a good indication that this operation has been performed before.....just sayin'. Those stud thread peaks look a little flattened in the 1st pic. I would use a few drops of thread locker with the new nut.