here are the schematics......

http://www.scottsbt.com/catalog/store/images/pennparts/schematics/340gt.pdf

http://www.scottsbt.com/catalog/store/images/pennparts/schematics/345gt.pdf

and here is your reel. the spools are the same as size as the penn 113hl and 113hlw, respectively. they are not interchangeable because the spool shafts are different.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4173.JPG

we are going to start by backing out all of the left side plate screws (key #'s 16 and 16A).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4174.JPG

carefully remove the left side plate (key #27), leaving the levelwind assembly in place.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4199.JPG

remove the spool (key #29L) and set it aside.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4200.JPG

find the bearing washer (key #153) and set it aside.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4201.JPG

lube the right spool bearing (key #55).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4203.JPG

lube the left spool bearing (key #40).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN42021.JPG

install the bearing washer (key #153), the spool (key #29L) and the left side plate (key #27). grease all the screw holes.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4175.JPG

reinstall the left side plate screws (key #'s 16 and 16L).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN42041.JPG

lube the worm gear (key #42).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4205.JPG

now, for the right side plate. remove the handle lock screw (key #110).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4177.JPG

remove the handle assembly screw (key #23).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4178.JPG

remove the handle assembly (key #24).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4179.JPG

remove the tension spring (key #8) and star drag (key #10). i typically discard the spring.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4180.JPG

ok, now this is important. see the gap here? the right side plate is actually two pieces, a right side OUTER plate (key #1) and a right side INNER plate (key #1B). to service the right side plate, you need to remove the outer plate and leave the inner plate in place. got it? good! ok, let's start!

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4181.JPG

remove the two long (key #31) and three short (key#38) right side plate screws. do not remove the spool tension control screw (key #26B) in the center or the eccentric screw (key #22).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4182.JPG

carefully separate the outer plate from the inner plate.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4183.JPG

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4184.JPG

if the gear sleeve (key #98S) is not badly burred, you can lift the gear cluster off in one piece. otherwise, you may have to pull the pieces off one at a time.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4185.JPG

here is an exploded view of the gear cluster. going top left to bottom right, you have a fiber washer (key #4A), the 113h main gear (key #5), five 113h carbon fiber drag washers (key #6), five 113h metal washers (key #7), a belleville tension washer (key #18), a bearing washer (key #4), a bearing (key #55A), and another bearing washer (key #4).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4186.JPG

to eliminate the sticking caused by the fiber washer (key #4A), we are going to substitute a penn ht-100 drag washer (part #6-855). i have noted that these washers will soon be in short supply. there is no problem using a #6-113H washer. and honestly, if you don't need the drag to be super smooth, you can even leave the original fiber washer in.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4187.JPG

it is very important to properly service the gear sleeve bearing (key #55A). carefully remove the retaining rings and shields on both sides, pack the bearing with grease and replace the shields and retaining rings.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4188.JPG

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4189.JPG

apply thick coat of cal's drag grease to each carbon fiber drag washer and rebuild the gear cluster.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4190.JPG

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4191.JPG

place a small bead of grease in each screw hole.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4192.JPG

carefully replace the right side outer plate (key #1) with the eccentric jack (key #11) in the "up" position and the eccentric lever (key #21) in the "back" or "free" position (not the "forward" or "in gear" position shown in the photo).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4193.JPG

replace the long (key #31) and short (key #38) right side plate screws.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4194.JPG

install the star drag (key #10) and turn it down until it clears the shoulder of the gear sleeve (key #98S) to properly install the handle assembly (key #24).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4195.JPG

install the handle assembly (key #24).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4196.JPG

install the handle assembly screw (key #23).

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4197.JPG

install the handle lock screw.

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN41981.JPG

and you're done!

http://www.fullspeedfishing.com/gallery/data/500/medium/DSCN4206.JPG

now for a couple of comments. the 340 and 345 gti's are basically 113hl and 113hlw's with a graphite frame and a levelwind assembly. these frames do not seem to be the most sturdy frames in the world. i've seen several frames come in pretty badly loosened up. not a good thing for a level wind reel. seriously not a good thing for a 4/0 sized levelwind reel. and for a reel of this size, it would be easy to blow out the levelwind assembly if the line tried to go one way and the leveler tried to go the other, particularly if the drags had seized up. regarding 4/0 sized reels in general, most guys are moving away from straight monofilament because of the stretch. with 100 feet of mono either straight out or straight down, it's like fishing with a giant rubber band. spectra is really the way to go. but if you're using spectra, a 4/0 sized reel is waaaayyyyyyy too big. so if mono is all you have access to and a graphite levelwind reel suits your needs, go with the penn 330, 340 or 345 gti. if you have access to spectra, go with the 320 gti or gt2. the 320's have the best power to weight ratio in this series.