JD310A won't pull forward

[gvette85]

I have a chance to buy a JD310 A backhoe that won't pull forward.All the hydraulic systems work and seem strong.It pulls in reverse fine and the owner says that it started slipping a little a while back and finally got to the point that it won't pull at all.The machine is a late 70's or early 80's and is in great shape.Paint is very good,tires almost new,and hoses all in great shape.It has had a regular maintenance schedule and the local JD dealer checked it out before this owner bought it and said all systems were fine.The price is very right but I think it needs a forward clutch pack.Any ideas?