i have a weird problem with the lift on my jubilee, it works pretty much normal with every attachment except my post hole digger, then when digging, it stops going down after about a foot and a half,most times once in awhile it will dig down to the gear head but not often, in checking, when i remove the lift arms from the digger,they continue on down to the lowest position, the upper arm of the digger is not in a bind and will dig with the lift arms un attached, when they are attached, forcing the digger down in the hole with the bucket of another tractor will raise the front of the jubilee off the ground, the u arch on the digger[ where the lift pins are attached] is not in a bind it swings freely, any ideas, as i mentioned all other impliments including pto powered ones work normally, i cant figure it out