Ht740 allison auto to big cam 3 cummins

[91eagle1545]

I have 91 m15 with a big cam 3 cummins. My question is can i take ht 740 allison from. 8v71 dd and bolt it to my big cam 3 with out lots of mods any help would be appreciated thanks john

[Jim H]

John, What transmission do you currently have installed in your bus?

[rusty]

John Just a WAG but I would think there would have to be some different parts to take the trans off a DD and put it on a Cummins. For what it is worth I have a big cam 4 with a 740 behind it and like it. I did not mount the trans to the motor so I don't know what parts are needed.

Wayne

[91eagle1545]

Jim i have a. 9speed fuller but a year ago i had a stroke and dont have good use of my left arm and leg so shifting. And steering is alittle tricky my wife wants an automatic i like the stick myself i have an ht740 i can put in out of a fire truck i think i need a different flex plate other than that im not sure

[luvrbus]

Doesn't the 9 speed use a SAE 2 bell housing the 740 takes a SAE 1,if you have the flex plate all you need is the center hub for a Cummins,if the 740 came a 8v71 you will need a different torque converter to handle the torque ,you are going to need to change the shift pattern and add a cooler too with probably a new drive shaft the rest is easy

good luck

[beltguy]

The subject of SAE bellhousing sizes comes up periodically. I thought I would post a couple of documents that might help folks sort out what they have.

SAE_Measure.jpg (55.71 KiB) Viewed 2994 times

SAE Bell Housing Dimensions.pdf

(325.19 KiB) Downloaded 576 times

Jim