Rear Spring Question-PT-105

[Richie]

Yes, that does help. I forgot that I have a cd of the '36-'48 master parts and I see the rear leaf spring chart 1. Those two assy. part numbers are for 9 leaf, one standard the other for wheels that are 18x362 or 20x325. So, thats not what I was hoping to find but looking at a Dodge truck '36-'40 condensed master parts listing   there is a large section on auxiliary springs  which is a section not in my Plymouth preliminary parts list for 1940...so I need focus on finding possibly a later edition that may contain auxiliary springs. Of course there is the possibility that a spring shop put these in and the springs are not stock, but thats what I am here to find out.
As far as the tranny, the PT-125 had a different part number for the three speed, as you pointed out (for just that one year) so I cannot make this direct comparison between the '40 and '41. There is a really good picture of the four speed in my parts manual so I just need to clean gunk and have a good look to I.D. this. Thanks for the input.

[TodFitch]

Probably not of much help, but the 1936-48 parts book shows the same part number (590170) for the rear spring assembly for the PT81, PT105 and PT125. On the next page of the book in a table for individual leaves it also shows a 590188 for the assembly. So I guess there were two possible spring assemblies.

Regarding individual leaves, the book shows:
PT81, PT105, PT125 using assembly 590170: Main: 590189, #2 leaf: 590190, #3 leaf: 590191
PT81, PT105, PT125 using assembly 590188: Main: 590188, #2 leaf: 590190, #3 leaf: 590191

I guess the #2 and #3 leafs have a quantity of more than one to to come up with the total leaves in the spring.

On the transmission, the parts book lists both 3 and 4 speed transmissions for all years. For PT57, PT81 and PT105 the 3 speed transmission assembly is 584623. For PT128 the 3 speed is 599750. For all 4 speed transmissions the assembly is 915490.

[Richie]

Doing some exploring now that I have the truck in a dry place. Helper springs are not listed in Plymouth Commercial car Preliminary Parts List 1940 Model Series (issued Nov. 15 1939). Attached pictures show the 9 leaf with a 6 leaf assy. above, second attachment is of PT-125 with just the 9 leaf standard assy. Is it possible that a later edition of the Parts List shows an option for this 6 leaf assy.?
Though I cannot yet positively indentify transmissions for the 1940 year, the tranny for the PT-105 is larger than the one in the PT-125. Suggests another heavy duty element, a four speed, which I am told adds a creeper gear.
The Style of the '40 is 4012, the '41 Style is 4112 if that is any help. Any input to indentify these springs and trannys would be greatly appreciated. Thanks, Richie