JD4520 Updates?

[Hay maker2]

John Deere 4520 updates.
Besides the engine, air filters, intercooler updates; what other updates or service bulletins where there on the 4520? Glen D Anderson posted info that I was looking for regarding the reservoir. I already had the bulletin regarding the valve. Any other bulletins or updates for the 4520?
Thanks

 

[GreenEnvy]

I thought they had to upgrade to fuel pumps too.

 

[grwrench]

hello,, the fuel injection pump was upgraded to i believe CBC 633- 38 AL if my memory is correct,, i changed some over back in the day, about 1970..