Will a Allison MT654CR live with a Big Cam ?

[74M35A2]

I called the local Allison /Detroit shop in Tulsa and talked to the lead mechanic. which happened to be a man of 25 years experience on the allisons alone, he told me the MT 654 was rated well below the power/torque curve. I asked because I put a 400 big can III in my 936A1 wrecker, and I was wanting to know if it would hold up to the power and not to mention the weight....41,000 pounds. I'm happy to report so far so good! another thing I will add is Cummins rates the HP at the flywheel, not at the wheels. there is a big difference. Caterpillar rates there engines at wheel horsepower! which is how it should be!!!

I don't think so.

 

[red]

I called the local Allison /Detroit shop in Tulsa and talked to the lead mechanic. which happened to be a man of 25 years experience on the allisons alone, he told me the MT 654 was rated well below the power/torque curve. I asked because I put a 400 big can III in my 936A1 wrecker, and I was wanting to know if it would hold up to the power and not to mention the weight....41,000 pounds. I'm happy to report so far so good! another thing I will add is Cummins rates the HP at the flywheel, not at the wheels. there is a big difference. Caterpillar rates there engines at wheel horsepower! which is how it should be!!!

No engine manufacturer rates the power at the wheels in the medium and heavy duty market because they don't know what drivetrain or stationary equipment will be bolted to their engine. There are tens of thousands of items that go behind each engine depending on who buys it. All of them are rated at the flywheel.

 

[PyroJoe]

Slightly on topic.... I've also got a bundle of 855 M939's as well as an A2 with the 8.3. The 8.3 gets my vote. The 855's are gutless turds! Currently contemplating between an 8.3 swap, a 400 big cam swap, or an LBZ Duramax swap (possibly with the Chevy trans/t-case). Would like to know how you feel about the 350/400 Cummins vs. the stock 250, and if you've driven an 8.3 5 ton, if you like the 8.3 or the big cam better. TIA!

 

[rwoody]

give me a ring

918 five eight 7841

have done this deal back and forth

 

[74M35A2]

Slightly on topic.... I've also got a bundle of 855 M939's as well as an A2 with the 8.3. The 8.3 gets my vote. The 855's are gutless turds! Currently contemplating between an 8.3 swap, a 400 big cam swap, or an LBZ Duramax swap (possibly with the Chevy trans/t-case). Would like to know how you feel about the 350/400 Cummins vs. the stock 250, and if you've driven an 8.3 5 ton, if you like the 8.3 or the big cam better. TIA!

Meow...

 

[av8or]

Woody, Care to make any of your thoughts public? If for one would like to know your thoughts. Bob

 

[CARMAN]

I called the local Allison /Detroit shop in Tulsa and talked to the lead mechanic. which happened to be a man of 25 years experience on the allisons alone, he told me the MT 654 was rated well below the power/torque curve. I asked because I put a 400 big can III in my 936A1 wrecker, and I was wanting to know if it would hold up to the power and not to mention the weight....41,000 pounds. I'm happy to report so far so good! another thing I will add is Cummins rates the HP at the flywheel, not at the wheels. there is a big difference. Caterpillar rates there engines at wheel horsepower! which is how it should be!!!

Meow is right. What was the end result? Need a MT654CR or simp suggests BH740 i think. for my 923a2. Can't decide if a "take out" is a smart move.

 

[74M35A2]

You should be able to get a good working MT654CR for about $500 plush shipping from here. I'd do that and be done. Or, I would try to get ahold of an Allison tech when his boss is around the corner, and see how much he wants in side cash to redo your trans at his house if you brought him just the trans. You just may be able to get it rehabbed back to near new for that same $500, or $500 plus parts? Guessing.

 

[CARMAN]

You should be able to get a good working MT654CR for about $500 plush shipping from here. I'd do that and be done. Or, I would try to get ahold of an Allison tech when his boss is around the corner, and see how much he wants in side cash to redo your trans at his house if you brought him just the trans. You just may be able to get it rehabbed back to near new for that same $500, or $500 plus parts? Guessing.

Put in the parts wanted and no replies. Found a couple take outs from a2 trucks who wanted the 8.3 but not the trans. for around $700. The Allison Dealer I went to seemed lazy as the 2 hour diagnostic included a pressure check and an estimate for a re-man install.

 

[Jbulach]

You better take a look at the gear ratios of that 4 speed, unless your going to really crank the power on the 8.3 up I doubt you’ll be happy. They are cheap and plentiful, I keep finding them behind a lot of the old road oilers in my search for a new motor for my parts truck.