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Cummins 6BT to Allison

shannondeese

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Location
High Springs Fl
A few weeks ago I posted about putting an Allison RDS2500 6 spd in my Deuce, the general concensus was that the LDT didn't pack enough power to make it worth while. I already have the Allison with the SAE3 bell housing. So I went back to the drawing board and got a Cummins 6BT 5.9 ltr from a Tug. So now I have another problem. The Cummins from the tug has a standard Chrysler bolt pattern. I now need a way to bolt these two together. I have heard that Cummins makes an SAE3 bell housing for the 5.9 but I can't find it. Any ideas where to look or do one of you have one laying around. Thanks a lot for the help. There are some bell housings on Ebay but I am not sure if they will fit the 5.9. I just don't know enough about this motor or trans.
 

Jones

Well-known member
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Sacramento, California
There are SAE bell housings out there for the Cummins. I got mine from a wrecking yard that does bigger trucks like Freightliners, Petes, etc.
You'll find the Cummins/Allison set-up in UPS and FedEx delivery box-trucks, armored cars, other trucks of similar size and purpose.
Everything should be there so get it all; bell-housing, flex-plate, flex-plate reinforcing plate, bolts, torque converter, starter (the SAE set-up DOES NOT use the dodge starter-- different bendix tooth count, different mounting bolt pattern).

Once you stop thinking Cummins/Dodge, a whole new world opens up to you-- notice the Bendix TuFlo 550 air compressor under the IP? It's a direct bolt-on, even has a power steering pump off the rear. There's even a mechanical tach drive for them. I also went with the high mount exhaust manifold; gives lots more pass. side engine accessability.
 

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mudguppy

New member
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duncan, sc
the only engine adapters i've found on the 6bt's are #2. not saying they aren't around, but just to make sure and measure for the correct bolt circle.
 

Jones

Well-known member
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Location
Sacramento, California
You're right but isn't there a 3-2 (or is it a 2-3) adapter sandwiched between the bellhousing and the trans on the deuces. Mine had a thin (5/8" or so) adapter and I'm pretty sure that's what that was.

I put an Allison AT545N behind my 5.9 and it was a direct bolt-up operation.
 

gringeltaube

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Speaking of med. sized truck 5.9 BT6s for (military) application I have seen a few of the low-outputs, (first generation, rotary pump, 97KW and 108KW vesions) coming from factory with the SAE#3 pattern bell-housing. And YES, the big brothers all are SAE#2.

Jones, just to remind you: the adapter ring on our MF is NOT a SAE#2 to - #3 one: the bolt pattern on the engine side is odd and specific to the 2.5ton MF versions, exclusively! See http://www.steelsoldiers.com/deuce/14719-ldt-bellhousing-sae-size.html

shannondeese, on your tranny I can find at least 12 holes, equally spaced, but would measure the bolt circle diam. and compare to the chart posted in that link, before start hunting for the correct adapter.

G.
 

mudguppy

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cool. i'd say jump on it - looks like it'll do you perfectly. [thumbzup]

besides, you will know if it fits within 5 minutes of opening it from the box.
 

HanksDeuce

Well-known member
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Location
Prairieville, LA
My receipt from a local starter shop indicates my 6BT with AT545 starter as part # 6582N. This replacement starter was installed in March of 2017 after the great flood of 2016 in Louisiana killed my original starter. My starter is bolted up on the passenger side of the bellhousing.

See pics on my website page below:
https://www.hanksdeuce.com/cummins_engine_install.htm
 
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