Opinions/Info on manual to auto swap MCI 7

[oldmansax]

I am toying with the idea of changing to an automatic transmission from the 4 speed Spicer I now have. Before I get excited, I thought I'd get some opinions/info on this particular situation:

The donor tranny is an unknown type Allison, currently in a 1976 Dodge, converted to a government airport fuel tanker by Consolidated Electric. It is a class 8 chassis with a 903 Cummins ((wimpy "triple nickle" V8) that is shot. It was bought by a local volunteer fire company I belong to & converted for tanker duty. I drove it many times & the tranny shifts well (4 times) and is tight. The bottom is covered 50 years of accumulated grease so I have not found any number on the tranny yet..... I have not looked very hard either! LOL

The questions are:

What flavor of Allison might be in a 1976 Dodge Truck?
Will it mate up to my 8V71?
What will have to be changed?
Will I need to change the gear ratio in the rear? (that would be a deal killer)
Do I need to install a tranny cooler & if so, where?
Is there anything I have overlooked?

Thanks!  TOM

[JackConrad]

   If the transmission is an Allison 740, looking at the transmission from the rear, the ID tag should be on the right side of the transmission, just above the pan and towards the rear of the transmission. You can take the model & serial number to an Allison dealer for complete information on that particular transmission.
   To install it on your 8V71, you will need a Flex Plate to replace the flywheel (don't forget to use new bolts when installing the flex plate). You will also need a transmission cooler and shift linkage (manual or air/electric), and probably re-do or replace your drive shaft (different length). Not sure about bolting to your engine. I do know the 740 transmission has 24 bolts that attach the transmission to the back of the engine.  Jack

[oldmansax]

Thanks Jack! The next time I am in the area, I will see if I can find the plate. Where is the cooler mounted on your bus?

Does anyone know about the gear change?

TOM

[JackConrad]

Looking at the engine from the back of the bus, the cooler is installed on the left side of the engine just above the oil pan flange.  Jack

[Dallas]

You'll also need what's called a double double oil cooler



If you find the housing, I have a spare oil cooler element.

Looking at the engine from the back of the bus, the cooler is installed on the left side of the engine just above the oil pan flange.  Jack

[Chopper Scott]

Do remember what I have encountered with an Allison in a MC 7. Overheating issues. The fans and radiators are marginal when adding the temp that the Allison adds and you would be well advised to also include an external tranny cooler also in your plans as well as the engine mounted cooler. I found that information on this board. Later

[TomC]

If this tanker has the Cummins 555, it's a good possibility that this is only a AT545-too small and without a torque converter lockup clutch.  Please inform us what you find.  Good Luck, TomC

[oldmansax]

TomC,

The tanker definitely has the old V8 Cummins. I am about 40 miles away from the station now, but will check on the tranny the next trip down. I just need to remember to bring my coveralls...

TOM