I have a 42 john deere la105 and a 48 inch bagger system. Can I use the hopper top and bags if I get a 42 inch upper and lower chute?

the blades are the wrong ones for throwing grass clippings
they have to have turned up edge to generate an air flow out of the chute to the bag
talk with the mower shop for the correct blades

grass catchers need special shaped or good blades to throw the cut grass into the bag
check/ replace the blades

Yes. I use gator mulching blades during the summer. They won't bag a thing. The original/standard blades will bag some grass/leaves, if they are dry and not too dense, but they are prone to clogging. The high lifts work much much better.

I get mine on amazon. The shipping is free. LA145 48" deck. Part GX21785.
http://www.amazon.com/gp/product/B00CAXMAG2/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1#product-description-iframe

ive got a JD 180 .with a bagger on it if you have the factory bagger
1st bolt bracket to back right hand side of tractor holes should allready be there next assemble bagger top to tractor bracket , hang collection bags (two) from top of bracket (open top to access) then assemble diverter tube all together three sections , snap end (wide) into bagger (no bolts needed) then fold back safety discharge cover on deck all the way snap the inlet adaptor into hole left by this (perfect fit) and last stretch rubber bungee up to deck wheel strut and place clip thru small moon clip there, now you willl need to replace your deck blades with the High Lift type (mulch) avail still from JD (theres a extra wing on back of it) this makes more air to scoot grass up the chute if not your gonna have a lot of cloggs

Try this link to Deere customer support:
http://manuals.deere.com/cceomview/OMM167392_B2/Output/Index.html?tM=HO
If that's not your model, look around - they do seem to have quite a few manuals online, and offer to sell you a paper copy if they don't have an online version. Good luck!

Try www.greenpartsstore.com

Curved edges go up.

is it a 42" or a 48"

The above is for a 42"

this is the lower cutter belt also the drive belt to the g/box is different

John Deere LA 125. Chute keeps clogging up with grass.