Cummins Diesel Compatible With Loadflite 727?

I have a Dodge Motorhome with a 440-3 and a 727 Lodeflite transmission.

It is my understanding that the Lodeflight is internally a completely different transmission than a Torqueflite 727. The Lodeflite is beefed up for heavy duty use.

I would like to replace the 440 with a 5.9 Cummins turbodiesel and I would like to keep the transmission, if possible, in order to keep the driveshaft emergency brake and in order to avoid modifying the driveshaft.

Is it possible to mate a Cummins diesel to a 727? If so, is it advisable?

Reply to
Paul Valois
Loading thread data ...

Bolt pattern may hold this up, but otherwise it should work. Internally, the LoadFlite is pretty much the same trans, just with more clutches. Things you'll want to consider:

Space for the Cummins: it'll be taller and longer than the 440.

Fuel system: You'll need a lift pump, appropriate engine controls, depending on model of engine, and a return line to the tank, as diesels have to have one of these.

Exhaust system: Space for the larger diameter pipe, and heat shields for the turbo and exhaust manifold.

Intake: space for the intercooler, and filter box, as well as the plumbing.

Reply to
Max Dodge

"LoadFlight" is a fancy name for the Torqueflight when installed in trucks, the internals are no different than those found in many big block V8 cars of the same era.

The 727 (37RH) used with the Cummins has a unique bellhousing bolt pattern, so a unit from behind a 440 won't bolt up. Your output shaft/tailhousing assembly could be swapped into a diesel case to maintain your parking brake and mainshaft. It would be wise to retain only the shaft and housing from your 440 trans and use as much of the diesel internals as possible, especially the governor assembly which is designed for much lower shift speeds.

Reply to
John Kunkel

I do not think it will hold up because it was not designed to operate at low RPM?s under a high torque levels countinously. There would be torque converter stall speed issues too given the diesel limited RPM range. Better off with the 440 in the motor home if you want to keep that tranny.

Reply to
SnoMan

You are leaving out another factor in this proposed mod/swap. The Cummins has a far more limited RPM range than the 440 so if used with current gearing it will likely top out around 60 MPH (give or take) or possible even less and the cummins when ran at its redline is not very fuel thrifty. So to do this you would have to swap rear axle gear ratios and lose your effective torque avantage on paper over the 440. You might gain a few MPG in this swap but given what it would cost to do it and the most likely loss of overall performance, it would be wiser to keep 440 and put the extra money saved from not swapping into the fuel bill. Besides, I think the days on deisel fuel being cheaper than gas are gone for good and from what I have been seeing in the futures markets, diesel will likely average 50 to 75 cents more a gallon than gas in the next year or so and that is before the extra 8 to 14 cents a gallon that the EPA mandated lowering diesel fuel sulpher content will add to price of fuel and it takes effect by the end of 2007.

Reply to
SnoMan

Interesting of you to say that. The LoadFlite trans has 4 discs in the front clutch, and 4 in the rear. Similarly, the 47RE has the same number, and is essentially the same transmission. Since the 47RE is the Dodge transmission assigned to Cummins duty, and it has the same clutch configuration as the LoadFlite, one will likely perform as well as the other.

However, since the OP mentioned that his parking brake was integral with the output shaft of the trans, its very possible he has a LoadFlite A345, which was a four speed AT, but with no OD. A good way to find this out would be to know if he had a "Park" position on his dash indicator. No "park", and its an A345.

While the TC would be an issue, its not hard to get a lower stall convertor in todays aftermarket. Clearly, cost isn't a big issue if the Cummins is under consideration. Furthermore, its interesting to note that if the A345 is in fact what he has, a 47RE will fit in that location, due to the longer case of the A345. Further, it would eliminate a cable actuated parking brake and put in a positive locking park position with pawl inside the trans, rather than out where weather plays a part.

Reply to
Max Dodge

You'll more likely find 5 discs in the front clutch of a 47RE and an equal number of pinions in the front planet as opposed to the 4 used in the 727 .

A drum parking on the tailhousing in no way hints at the presence of an A345, the 727 installed in these motorhomes usually has the drum brake.

Since the 440 trans won't mate to the diesel the point is moot

Reply to
John Kunkel

2000 FSM says 47RE front clutch has 4 discs.

Which is precisely why I noted the best way to tell was by whether or not he had a park position on the shifter. You did read what I said, correct?

Unless someone makes an adaptor, which is also possible.

Reply to
Max Dodge

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.