I have a 2011 D6T dozer that dosent lower the blade like it should. In the past the blade had three positions; when you pushed it ahead a little it would lower slowly then if you push it ahead even further it would drop really fast, and clear ahead it would go to float. Now when ever I run it and push it ahead 3/4 of the way it drops really slow, and when ever I push it all the way ahead it causes the cylinders to chatter loudly and still lowers slow. I wonder if there is valve some where that is being restricted and/or not being opened all the way? I was wondering if anyone has ran into a problem like this before or knows what might be wrong? thanks,
Is the linkage ok
Yes, I had the same thing happen on a rental dozer about the same year model. They tore into the quick drop valves and took the seat and floorboard out going through some valve but they never did find the problem. This one didn't make any noise it just wouldn't lower the blade fast.
I 2nd looking at the linkage. The D7R I took care of acted funky like that and it was a linkage issue. All the hydraulic components themselves were fine. Start with the simple stuff and work your way into harder.
check the quick drop valve as there are some mods Mark
fixed mine today it is a lay sn the pilot accumulator had lost its charge