Joined: Jan 16, 2015 Posts: 6 Location: Goldsboro North Carolina
Posted: Thu Apr 09, 2015 5:30 pm Post subject: M series speedometer info needed
Picked up an M series speedo recently; radium numbers. Marked:
MS 39021-1
S.W. 503A.
Has minimum gradient lines (only on the numbers). Not sure how to post pics. Any info on this-if it was used on the M38--be much appreciated.
Thanks!
Joined: Jan 16, 2015 Posts: 6 Location: Goldsboro North Carolina
Posted: Thu Apr 09, 2015 8:11 pm Post subject:
Thanks Brian. I'll look into this speedo further. Very different. Really just curious on what it was made for.
Appreciate the heads up on the AC speedometer.
If you look in the 1955 ORD 9 SNL G-740 (M38 Parts Manual) on page 2210, you will find both the AC # 1580260 and the SW # 503A and also the WO# 118101, the ORD PN 7760396 and ORD Stk # G742-7760396.
If you look in the 1956 M38A1 ORD 9 SNL G-758 (M38A1 Parts Manual) on page 372 you will find two separate Speedo entries:
AC # 1580260 and the SW # 503A and also the WO# 118101, the ORD PN 7760396 and ORD Stk # G742-7760396. (luminous dial) (Used with cluster 7418835 [this is M38A1 up to SN MD70114]) (Superceded by Speedo 8376375)
AC # 1582373, SW # 503C, AL # EO-12205, WO # 809819, ORD PN 8376375, ORD Stk # G742-8376375. (non-luminous dial) ( supercedes 7760396)(Used with clusters 8376619 [Used on M38A1 SN MD70115 & up], 7954878 [M170], and 7954879 [M170]).
Looks confusing, doesn't it?
Notice no MS39021-1? That's because the MS numbering system didn't replace the old ORD PN in supply manuals until about 1958-60.
This can all be misleading because none of it tells you what the jeep left Willys with. The short answer here is the AC # is the correct number and about 1955 the luminous was being replaced with the non-luminous.
To answer your question "What was it originally made for?" is tough. The Ordnance Stk # always showed the first vehicle an item was used on, As you can see in both cases the G742 is used and it represents the M35 2.5T truck. This really doesn't answer your question because you are not interested oin what vehicle first used that ORD Stk #. You want to know which vehicle that Speedo in your hand was built for. The only answer I can give you is: 1-It was a second source vendor unit built for spares in the supply system, 2-A GM tactical vehicle used by the military and produced before 1956. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Jan 16, 2015 Posts: 6 Location: Goldsboro North Carolina
Posted: Fri Apr 10, 2015 3:24 pm Post subject:
Thanks for the reply Wes. It is a different looking unit and I was curious about it's original use. I don't own all the parts lists etc and appreciate those of you good folks who do sharing the info.
Joined: May 30, 2014 Posts: 3447 Location: Texas Hill Country
Posted: Fri Apr 10, 2015 3:50 pm Post subject:
Hi Vince,
By being a member of this site you have access to and can own all of the available manuals and parts lists.
Just look up to the left of the page under Navigation and click on Downloads.
There you can download Operations and Maintenance manuals for the M38 as well as M38A1, complete service parts lists for both, as well as a host of other manuals and parts lists and other info free for the asking.
Be sure and thank those that have taken the incredibly valuable time to scan and download them, as I do every time I look at them. At least out loud.
I use the Ord 9 740 list almost every day, and certainly any time I am checking out something for sale on line or before a parts run to the hardware store.
Posted: Sun Apr 12, 2015 6:48 am Post subject: G number assignment
Hey Wes,
I would disagree with your explanation of the G number assignment. Simply because it started G742 does not mean it was only for the 2.5 ton gas truck. In the standardization of the M Series parts system, that part number could and would show up in a multitude of Ord 9's. They were trying to eliminate the over purchasing of parts that happened in WWII by standardizing the common parts. I would venture that the gas G742 truck may have had contracts let before the G740 contracts were let. Having said that, this would be the reason why a common part such as the speedo in this case would have been assigned a G742 prefix rather than G740. Further, since it was a common part, and they were sourcing the purchase of these parts for the build of the jeep, they would not have to research this because it was already done. They would have used the same vendor for the purchase and the same part number until he government changed the vendor. You stated that both SW and AC show up in the Ord 9 prior to the change to the MS system. I would then argue that both speedos were and are acceptable as there was a change in government procurement which they noted by having both referenced. I do not have an early Ord 9 sitting close by. So my only question is prior to the 1955 Ord 9, was there only a listing for the AC speedo, or did it reference both numbers then as well?
John
John, If you read my post closely I did not say that. I said:
Quote:
The Ordnance Stk # always showed the first vehicle an item was used on, As you can see in both cases the G742 is used and it represents the M35 2.5T truck.
As you can see I said the ORD Stock # prefix ID's the first vehicle the number was used on. (not the only vehicle) Then I explained which vehicle the 742 ID's.
It's a system I worked with for 22 years and I am quite familiar with it. My definition above is from the SNL's general info pages.
The AC and WO #'s are listed alone in the manufacturer's column of the 51 ORD 9. So the original from Willys unit was AC however the Army supply system stocked parts at that time using the Army stock number G742-7760396. Therefore any speedo meeting that ORD PN 7760396 was eligable to be used as a replacement part on the M38.
For example if I ordered G742-7760396 from that 1951 M38 ORD 9 in 1954 supply would have issued what was avialble on the shelf and that could have easily been a SW 503A. However had I specifically ordered by manufacturer's part number and specified "No Subs" on the request they would have hunted down the AC# 1580260. This was tough because it usually meant backordering the part manually to the OEM. That would eat up a lot of time.
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