I have found entire doors a you pull it Junk yards. I also have a 77 but a g10. I replaced my whole sliding door with one with opening pop out widows from an 80's g20 van. I imagine that the g30 should be the same as the g10 and g20 from any years up to 95. I imagine it would not be expensive from a junk yard since you do not need the whole door,. simply take apart the part you need in the yard from the vans in stock. if you not near a junk yard. i guess ebay would be the cheapest route I