So, here is how I did it (only because I was not able to inject grease into the gearbox from the underside of the truck)
remove the cab and shell as described in a previous post.
remove the speaker housing by unscrewing its 4 screws.
That will expose the single screw holding the truck to the chasis
Unscrew that screw and that will allow the truck to fall away from the chasis. Pay attention to how the coupler and p/u and ground wires are routed.
Unscrew the 2 small screws on top of the gear box. There are two screws on bottom of the gearbox (underside of truck). One is a grease port (i think that is what it supposed to be) the other is a long screw that holds the truck halves together. I can't remember which is which, if you unscrew a short screw then tighten and go for the other one.
With a small flatblade screw driver I separated the gearbox halves a squezed lithium grease on the worm gear and in the cavity too.
I screwed the gearbox back together.
The worst part of this was mating the driveshaft back together. Once you get them mated screw the truck back to the chasis from the topside.
Here is how my SW7 after a little work...
Excellent sounds, the little fatboy speaker kills the ridiculous pancake speaker in my Legacy S2 switcher.
Fixed Pilot with SIMPLE Kadee installation-thank you Lionel!
Excellent detail, this body is actually an SW7, not the NW2 as advertised by Lionel a couple years ago (I left my dealer holding the bag on 2 of those supposed "NW2s").
This engine matches VERY closely the pics I found on line-even the color of the bell..good job Lionel.
This is a GREAT smoker!
This engine has the little PCB that emits the sensor track beam, which I think is very fun.
Come on, no grease in the gearbox?
Both truck screws were loose (how can a repeat of the NW2 debacle be allowed to happen?)
While I greatly appreciate the fixed coupler it would be great if Lionel offered a pilot insert to close up that gaping hole. They go through the trouble of pre-drilling the chasis and providing a coupler shim so why not finish the job so we could have a more prototypical front end.
All in all I am pleased with this engine. I was going to open it up to unplug the couplers and glue in Artistta figures, so working on the gearbox was not the end of the world for me. But if I had wanted to play with this engine as soon as I unboxed it I would have been hacked.