Swapping shells between old and new Atlas GP38s

[DevalDragon]

I have 3 Atlas GP38-2s from the early 2000's I want to install sound and DCC. It seems the easiest way would be to buy some of the new Atlas Gold series models and just swap the shells. I have heard that the drive assemblies are completely different between the old and new Altas models. Will the shells still fit? Or will I need to modify them somehow?

[peteski]

Spookshow (Mark) has an excellent write-up covering all the various releases of Atlas GP38-2 and GP40-2 (they use the same mechanism).
See http://spookshow.net/loco/atlasgp3840.html
While I have not done it myself, I suspect that the older shell will fit new chassis.  Maybe someone else will chime in too.

[Ed Kapuscinski]

I have done it with a GP40 (actually, a GP40 to GP40-2) and it seems to work fine.

Ironically, that works better than the factory GP38 I got which has a weird thing with the shell sitting slighting high in the front. I think I fixed that by removing some electrical tape that was inside the shell, but it was odd.

[Lackawannae8]

yes its a direct swap

[Dupesy]

I had a little issue with this.  I tried an GP38-2 shell from a new-ish run on a new sound-ready GP-40 mechanism and found the shell rode too low on the mechanism.  However an even OLDER GP38-2 shell (from a high speed motor chassis) fit the sound mechanism just fine.  I found this to be rather odd.  The coupler in the older shell matched a micro-trains gauge perfectly, the newer shell was almost half the height of the coupler face too low.  My suspicion is a tooling issue with the newer shell; I have 2 from that run (Guilford units) and on the mechanism they came with they do ride a touch low.

[pastoolio]

The only issue I have ran in to is the lighting. The newer shells have a large plastic insert in the roof of the cab to eliminate the old "cab glow" when the head light is on. When you put an older shell on a new DCC/Sound mechanism, the LED's light will spill out in the cab. You'll have to get creative with adding a light shield, since the new mechanism doesn't have the recessed areas for the old black light shield to fit in to.
And if you want to put a new shell on an old mechanism, that's even more of a P.I.A. since the large LED's of old interfere with the plastic insert in the cab roof.

-Mike