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Discussion Starter · #21 ·
Picked up a real clean Allison 2500. Looks like all the motor mounts will bolt straight up and it has the correct bellhousing.
my current flywheel has a snub that sticks out too far for the new trans. Doing some rough measurements it appears I need it about 1.25”-1.50” shorter. I could easily make a spacer if the flywheel was too short/not thick enough. I’m even considering having this one machined down and making a new pilot insert but I’m attempting to find the proper flywheel first.
If I come across any relevant part numbers I’ll post them here for future references.

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Discussion Starter · #23 · (Edited)
Found some good info:
Attached are some flywheel application guides. It lists my current flywheel (5170516) as applicable to the MT-41 which is what I had.
It lists the correct flywheel for the AT-40 as 5147282. Quick search turned up nothing, if anyone has a 53 series flywheel lying around with that part number on it, please let me know.

Update: 5147282 is the detail number. The assembly number is 5147702 which is available through some online stores



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Discussion Starter · #24 ·
I’ve was comparing the flywheel I have for the MT41 (5170516) to the one referenced for the AT545 (5147282). Turns out the measurements are nearly identical. Went out and remeasured and and turns out I didn’t have the TC fully seated. Now it seems I’m within a few 1/16ths of an inch. I’ll drill the new pattern on the flex plate and bolt it up to see how close it really is. I suspect it can be used with a few shims to get proper TC clearance.

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Discussion Starter · #26 · (Edited)
EDIT: Found the correct flex plate after some digging. Detroit 5107769

Hope this helps someone else along

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Centering boss does match. All I have left to source at this point is a flex plate. Worst case I can drill mine out to the 11.5” on center bolt pattern for the 2000 series.
 

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Didn't your MT 41 have multiple thin discs for a flexplate ? You found the very handy flywheel and housing book that I have, but mine is '70s vintage . In my '70s Allison application manual the flywheel coincides with your info, but flexplate in my book shows 5147281. I scrutinized all the dimensions as listed and see no reason why not use your original flywheel from the MT 41 , and just use updated flexplate . Regarding flexplate, you state you need 5107660, but the MTU listing is 5107769 . This has me confused. I'm well aware of parts like a flywheel that has a detail #, that becomes an assembly with the addition of the ring gear . You've done your homework correctly .
 

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Discussion Starter · #28 ·
Didn't your MT 41 have multiple thin discs for a flexplate ? You found the very handy flywheel and housing book that I have, but mine is '70s vintage . In my '70s Allison application manual the flywheel coincides with your info, but flexplate in my book shows 5147281. I scrutinized all the dimensions as listed and see no reason why not use your original flywheel from the MT 41 , and just use updated flexplate . Regarding flexplate, you state you need 5107660, but the MTU listing is 5107769 . This has me confused. I'm well aware of parts like a flywheel that has a detail #, that becomes an assembly with the addition of the ring gear . You've done your homework correctly .
You’re correct, the MT41 has the 4 flat discs but the bolt pattern for the heavier duty Allison torque converters is slightly different. Also, those torque converters are flat faced which allow those discs to clamp to it. The 545 and 1000/2000 series need a more modern looking flex plate due to the raised mounts.

5107769 is the correct number as you said. I must have fat-fingered the previous post.
I was able to locate and purchase the flex plate today for $280 shipped. Bit pricey but if it allows this to all bolt together it will be well worth it. It arrives next week so I’ll update you on real life fitment.
 

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I had the older 5147281 , I'll look up price in my 1988 price book...................just out of curiosity . Yes, you'll have all the right stuff, no mickey-mouse ,that could take out the thrust of the engine..............or the pump in the trans .
 

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I had the older 5147281 , I'll look up price in my 1988 price book...................just out of curiosity . Yes, you'll have all the right stuff, no mickey-mouse ,that could take out the thrust of the engine..............or the pump in the trans .
88 parts book showed obsolete with no supersession information .
 

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Discussion Starter · #33 ·
Cool truck! Mines a ‘70 Chevy as well. Wish I was man enough to run a brownie but my curiosity got the best of me wanting to see modern technology behind a 2 stroke.
 

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And I sold Allisons for 16 years. But I sold an AT 540 coupled to a 4-53T and company employee installed it in a '70s Suburban . I put probably 300 miles on it before delivering it to a customer in Pennsylvania . I didn't like how it would freewheel when you took foot off accelerator . It happened in the late '70s before a diesel lowstall converter was offered. I also obtained an MD 3060 takeout in 2009, with thoughts of removing both transmissions . I think you have the ideal setup, because you can control gear selection . Like yours, I have a high silencer Donaldson muffler .
 

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Discussion Starter · #35 ·
Budget is forcing me to use a stock TCM for the time being. What Stock TCM should I order to make the truck "usable"? I plan to tune later on but just to get the truck running and driving. Would an '06 Chevy 8.1 gas TCM have similar shift points or should I stick with a diesel tune? any Allison applications that have a somewhat higher revving diesel?
 

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My experience was with the prior generation of '72-mid '90s and the valve bodies would be programed to maximum load conditions, which could be too jerky for light loads factor of a pickup . The current generation including 1000, 2000, 2400 are probably more sensitive to light load-part throttle conditions of a daily driver . But I'd think I'd try to get a TCM from a diesel school bus application .
 

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When I picked up my 2400, I took the TCM from the F-650 that was wired to it. It should be a fairly good fit, so I'll use it as a starting point.
I'd stay away from the 8.1 gasser, as I think shift points would be much different.
 
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