-did the weld and re-drill on the linkages for the blade, what an improvement! definitely worth the time and effort

-do you have the part number for the interlock linkage spring?

The blade is where I'm headed when I get the redrilling figured out. My blade linkage is well hooped out. PN 7H0610 for the interlock spring.

Spent most of the day working on the D6. Got everything freed up and back into spec'd adjustment. I've got positive engagement on the interlock in each direction. Got the flywheel clutch lever readjusted to book spec after all the readjusting needed from the new clutch brake and drum, which like I said previously, I think had helped contribute to the damage to the interlock shaft. The old tractor should be ready to go now, after I finish the other things I want to get done. Again, want to say thanks to everyone that's offered advice, it's greatly appreciated.

-took a closer look at my interlock linkage, pins and clearances tight, looks good
-the 15.25 inch length adjustment is correct

-what condition(s) would a weak spring on the interlock produce?

My measurement was correct too, with the old spring. I didn't realize how weak the old one was until I had the new one side by side. There was nearly an inch difference. With the new one in place I had to make a slight adjustment, but the engagement is definitely more solid. I'm sure part of that is the new shaft, without the massive missing chip.... But I think the spring is there to keep pressure on the linkage.

that's quite a difference and loss of spring tension
-do you have a length measurement for the new spring? i read 6.500 inch somewhere for new

I don't have the measurement, and I thought I had a picture, but 6.5 inch would be about right. There was enough tension difference to make it difficult to install the new spring.

looking for an update please....did you manage to get some seat time and work done with machine? staying in gear? any issues?
- trans?
-trans brake?
-shifting?
-hope it's all good go to go and 100 percent

Work has gotten in the way on the decent weather days for me to get the tractor finished up, but I've had a little time lately to work on it. The biggest update I've got is that I changed the transmission filter and cleaned the magnetic screen. The transmission filter looked pretty fair, but the magnetic screen and it's filter are pretty nasty. I definitely need to change the oil there. Am in the process of brake adjustment since the majority of the platform is out of it anyway. I'm also going to pressure check my steering clutches since I'm there. Made some other repairs, and rebuilt the blade linkage. I went from two or so inches in either direction of play in the blade lever to maybe a half inch now, so that's probably the biggest win I can claim right now aside from the custom seat back and armrests I cobbled together on a couple of rainy evenings. I'm hoping an oil change will clean up the transmission and I don't have some bearings on the way out.

a oil and filter change is always a good first step. and its relativity cheap.