mt 654 replacement or repair for a m923

Alright guys, these might be some silly questions but i am in a bit of a bind. I have an m923 that the transmission cooler/heat exchange line, made contact with the exhaust manifold and cracked. This lead to the transmission draining out while going down the highway with out me noticing for a pretty long distance. Once we stopped we noticed that we only had reverse. so we had the truck towed back to San Antonio. I repaired the lines and refilled the truck with fluid and it still only has reverse. If the truck is in R its goes into reverse, if the truck is in N its goes it reverse, if the truck is in 1-5 its does not move, if you give it throttle, it only lets the truck come up to 1300 RPM. Once you turn the truck off, and starts rolling forward pretty rapidly for about 12 feet. So i pulled the transmission oil pan and it looks pretty bad in there.

So the questions are:

is the transmission shot, or is there something im just not doing right.

if the transmission is shot, what is he best way to fix it? is there some place that rebuilds these transmissions? or should i get a Pull Out?

if there is a place that rebuilds them or sells pull outs or even new ones , does anyone have any contact info?

or do any of yall have one for sale?

last an final question is i have found a few non running truck on GL for pretty good prices, should i just buy one and pull the transmission out of that?

Any help would be appreciated!

Replace it, you melted some things inside. You probably can get a whole truck for close to what just a surplus transmission will cost you, unless someone here has a used takeout. Post up a want ad in the classifieds.

WOW , lots of questions , maybe I can answer a few as best as I can . Sure sound like you cooked the unit , but I would try a filter and fluid change first and get a trans. oil pressure gauge and check your pressures , and that will answer your one question . The rest of your questions come down to ability/time/money . Take-outs/used units are a crap shoot , same as buying a NON-RUNNER from GL , could end up with the same problem OR WORSE ! Best bet IMHO depending on your skill level is a KNOWN good take out , last would be a Allison rebuild , if you can do some of the R/R you can save some cash , but removing a 5 TON trans. takes some GRUNT ! good luck , Bob K

I would have to agree that if you ran it that long, losing that much oil, and now it won't go into forward gear, then you cooked it, so your now looking at a replacement or rebuild. I tend to agree with the other member,cost wise i would look for a good pull out being sold by another S.S.member. Still if you get a good pull out, unless you have a good home shop, along with all the tools and extra manpower, you may still need to have a shop do the R&R for you, but your the only person that can answer that question.

You might could get a new one from GL if you are not in a hurry. I saw a bunch of new ones sell pretty cheap out in Oklahoma recently. I bought a M926 a while back cheap enough that I could part it out and come out ahead since the engine, transmission and tires are all good. I have a transfer case to put in if I get around to it. I've looked at some of the vendors and it seems like the prices through them are pretty high. You could also check with csmdavis in Mississippi, he parts out trucks and gave me a deal on the aforementioned transfer case.

Centex Salvage in Killeen bought a bunch of 923s that they are parting out. That would probably be the closest place to get a take out. Only problem is you're getting an unknown entity so I'd advise not paying more than scrap value for it.

And since you're in San Antonio: http://www.steelsoldiers.com/showthread.php?109800-San-Antonio-TX-Monthly-MV-get-together!!

Trailboss said:

If you only expect to pay scrap value, no one will want to spend the time and $ to remove or handle the part for you - they will just haul the truck to the scrap yard. I haven't looked lately, but takeout M939 transmissions should cost around $500, and transfer cases about the same.

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This is a scrap yard that's just selling some parts. I imagine he'll want something over scrap value but shouldn't be much more. Since he's not guaranteeing it'll work he shouldn't be getting full price for them.

There is a AWSOME Allison rebuild repair install shop in Upland California called
Precision Allison Transmissions. There are semis coming and going from
this place daily delivering and sending back Allison trannys. They have a
Dyno, the shop is immaculate and they are old school in workmanship
and quality.

There phone number is 909-949-8777. The owners name is Dave. I was
there recently and took a brief an Iphone video of the Dyno in action.
They do it all, School busses, MV's, Garbage trucks, Rental trucks,
police heavy haulers, you name it. Two Thumbs UP from me !
Tell him I sent you, verify before you call but most M939
Series automatic transmissions are the MT654CR .

https://www.youtube.com/watch?v=pK1JOhJwvc8

Hey guys, thank you for all the input! I ended up taking the truck to a friend of mines shop, we pulled it and had grande truck center repair the transmission. We just installed the trans this week and i started it up and its leaking fluid out of the rear seal where the rear yolk comes out. we are kinda stumped as to what is causing it to leak.
I was hoping to have the truck done in time to come to a meet or go to Mud Fest this weekend.