***C4 auto not shifting---need ideas ASAP***

[chuzie]

The C4 Auto in my 77 was shifting pretty hard before I placed it in storage 2 years ago. I would have to get the RPM pretty high and then let off the gas to get it into 3rd especially and then it would CLUNK once really hard when it did shift.

I have not installed any mods in the tranny but can't say what the person before me did or did not do.

I have plenty of Type F fluid and yes, I check it correctly.

I tightened both band adjustors as best I could but really couldn't get my torque wrench in there so I had to use my calibrated elbow to wag 120 inLb and then back off accordingly. They are pretty far in there though so that is a thought that maybe I am just worn out.

I have not pulled the valving yet since I wanted to see if there is a external fix first.

I check to make sure the linkage is secure and I do get all my detents on the shifter and I am not running in between a set.

I could tow it to a tranny shop but I will need some recommendations and what fun is that to have a mechanic do the work for you? I am certainly open to doing a C4 rebuild myself if it is necessary.

Ok everyone, give me some troubleshooting ideas to get this thing shifting again. It sat for 2 years and stopped shifting. Sounds weird.

-Mike