T90A1 Casting Codes

radtech · Post by **radtech** » Mon Mar 19, 2018 2:01 pm

I found 12-9 on an original 50 Studebaker truck T90A1.

dpcd67 · Post by **dpcd67** » Mon Mar 19, 2018 2:56 pm

Yes, I have an RMC 58000 engine and what is probably a matching transmission; not incorrect at all; it is a period correct DS maintenance replacement. My jeep is all like new, (restored) including the engine and transmission. It is the best I could do with what I had. So, ok, motor pool, that looks like it was just delivered.
I still want to know when the transmission was made.
Motorpool? Engines are not allowed to be replaced by the "motor pool", meaning Organizational maintenance, then or now. Common misconception. That is a third echelon, Direct Support Maintenance function. Or higher.

4x4M38 · Post by **4x4M38** » Mon Mar 19, 2018 3:25 pm

My motor pool comment was referencing restoration and contest
catagories. What might be allowed in a motor pool class restoration
would not be allowed in factory class.

Take care,

radtech · Post by **radtech** » Mon Mar 19, 2018 3:50 pm

It is highly doubtful that they would replace a good transmission and transfer case when the engine was replaced.Also the engine could have been replaced after they surplussed them out.I have seen several NOS RMC engines in the original crates.

Post by **wesk** » Mon Mar 19, 2018 5:53 pm

Looks like a summation is in order.

1-I have seen engines changed in motor pools in the 60's & 70's. Both US Army & US Air Force. But for the sake of clarity for the Army side of the house folks tend to over generalize the term Motor Pool to include both Organizational and Field level maintenance shop facilities. Engine changes are normally a function of the field or higher echelons of maintenance and that facility technically is not a Motor Pool.

2-We have been able to ascertain that your replacement tranny is not correct for your jeep.

3-We have already ascertained that there is no available product any of us has seen that can be relied upon to accurately decode any casting codes on these later T90 trannies. That said I see little chance for you to positively determine the DOM of your replacement tranny.

4-This is a hobby. Unfortunately the object of this hobby is more than a Half century old. No one short of a God has the ability to positively ID any part of any military jeep to be original to that specific serial number jeep. For post war jeeps that all came with only two serial locations for the chassis/body and both were screwed into place and easily swapped with any jeep cannot even determine 100% that the jeep you are looking at is really that serial number jeep! Willys & Kaiser did not match engine serials to jeep chassis/tub serials for postwar jeeps. Therefore unless one is graced with the vision of the Gods there is no way to ascertain when that engine found that jeep and weather that engine change included a tranny/transfer or weather that engine change was conducted in a military facility or in the third civvy owner's garage.

My first jeep was a 42 GPW I bought in Louisiana in 1971. Then came a M38A1 in 1987. I waded thru the bulk of these questions before the advent of the World Wide Web! Back when it was pen & paper or the phone. Answers to hard questions often took several years to get back then. Today we get a lot of these answers in less then 10 minutes. But today we saw that one answer is not out there right now. In time it will appear. This is the part of the hobby that requires a lot of patience and determination.

radtech · Post by **radtech** » Mon Mar 19, 2018 8:21 pm

Correct.When I bought my M38 there was no internet but fortunately my father had worked on them from 1950-1970 and knew just about everything about it.The only way to get questions answered in those days was to go to the library find a book with a name and address to write to them.In those days you could buy parts for next to nothing so I made sure I had at least two of everything.Fortunately My M38 has the date 12/1950 on both axles and transmission as well as the early body and frame and serial number plate 10675.

dpcd67 · Post by **dpcd67** » Mon Mar 19, 2018 9:54 pm

I fully understand what I have and the various ways it might have got that way; as I said, that is all I have available and everything has been rebuilt, so this set is what is going into my M38. I have restored several Jeeps and Dodges; I do not take them for judging.
As for the motor pool thing, I know you were referencing the judging aspect.
I was in many motor pools (mostly tank) in my 28 years in the Army in the 70s through 90s. And I worked at TACOM for many years after that. so I have been exposed to some maintenance policy. . It was impossible for any of the units I was in (and I was BMO in one) to requisition an engine for anything; the only way was for the DS unit to provide it and install it, which they did for tank and 113 engines because it was easier to bring the engine to the motor pool than take the tank to them. But for wheeled vehicles, the vehicle had to go to the DS shop. Anyway, any Organizational requisition for an engine would be treated the same as a requisition for a submarine; it would be cancelled. Maybe the Air Force does it differently.

Post by **wesk** » Mon Mar 19, 2018 10:45 pm

We didn't do things differently in the Air Force. Just with a bit more flexibility which is why I did only one term in the Army and went USAF for the remainder. I've borrowed help from upper echelon for wheeled maintenance in the 60's when necessity and common sense was more important then quoting doctrine. It can be difficult in some commands but if you look hard enough you can often find high levels of cooperation between maintenance echelons.

dpcd67 · Post by **dpcd67** » Tue Mar 20, 2018 8:58 am

Yes, I talked to and often visited the DS unit commander and Maintenance Tech (always a crusty, old W4) every day; that is the only way to survive in a tank battalion. High levels of cooperation are key to success. We had a DS unit team stay, live, and moved with us in the field to perform DS level work for us, on tracked vehicles. Led by a female sergeant who was a better mechanic than any.
OR rates below 90 percent could get someone fired. The poor Infantry guys never caught on, and they suffered in the monthly maintenance reviews with the DCG. But it is not just a question of blindly following doctrine nor a lack of common sense; Organizational mechanics are not trained, equipped, nor have the time to perform DS level and above tasks. The system is set up that way for a reason. And you can't circumvent that system if you wanted to; where would you get the parts from?
My only point is to try to educate the young guys who were never in the Army and who think that all kinds of repair and replacement was performed in the "motor pool", meaning at Org level. Just not the case.