4050tn ligt gradient printing

I'm working with a 4050tn. Printing regular text seems dark enough (maybe not as crisp as brand new) but areas that are supposed to be filled with a grey gradient (for instance the grey HP background on the menu map and config printable pages) are really light. the toner was low, so i replaced the toner and reset the toner life. I adjusted the toner density to 4, rather than 3, and it did improve some. the maintenance kit has about 40,000 pages. what should i be looking for to fix this?

thanks

eh... well I found the fix.

After comparing printouts from this 4050 with a few other printers, and comparing things, the 4050 was not using PCL6 drivers, and the other printers that printed the shading fine were, so i updated the drivers on the 4050, and it's better now.