arcane secret to installing new Davenport drivers?

[on30gn15]

Okay, what's the arcane secret to installing a brand new set of Davenport drivers?
Apparently merely getting the gears on the correct side and engaged with the quartering properly lined up isn't good enough.
After multiple tries all we get is no revolution to one revolution then the axles jam.
Transmission runs fine without axles in, so it probably isn't something with the internal gearing.
I've been doing model trains for four decades, I should be getting this right by the seventh try, ya know.
IMG_2717_50 by ,

[2foot6]

I'm sure you would have tried this ,but make sure the side rods are parallel to each other and parallel to the foot plate of the loco.Also try just moving one axle one notch left then right and check for rotation each time .If that fails remove the side rods from one axle and check the rotation............................................................good luck..Peter. 

[on30gn15]

Hey there! I also wondered if the little tabs at end of siderods, tabs which represent lubrication cups, were jamming against bottom of deck and reversed drivers to put those table on the bottom, nope, not the source of the problem.
Even pulled the central gear to allow the front axle to freewheel, that really didn't work!

In between original post and just now, got it to run forward a bit jerkily, but not run at all backwards.

I'm moments away from deciding to dump the siderods and counterweights and throw together something to represent an outside frame like on this 20 ton Baldwin of similar silhouette though larger size.
http://www.northeast.railfan.net/images/kvpc20.jpg
And, actually, I think I just now have settled on doing that.
I'll say it was a roller chain drive variant.
That mechanical drive Porter has an interesting frame, http://www.rr-fallenflags.org/porter/page52c.jpg