Has anyone out there adapted an old school 5 or 6 speed Allison over to a Navistar diesel? I need more gearing for the highway and I want an automatic. I've heard of the 4 speed being used with an adapter but with electronic issues and the durability in question. I am assuming of coarse that the older automatics are not electronically controlled.

 

yes it can be done they came with them factory in medium duty trucks. You will need to get all the parts from a medium or heavy duty wrecking yard. You will need

new delco starter (changes sides to drivers side)
3 inch SAE spacer plate
flywheel
transmission
linkage(custom made)
cooler lines
remote filter mount

 

You're going to find that a older generation non electronic Allison for the most part isn't going to help your case. The majority of them are non lockup, with a 1:1 top gear, no overdrive. The lack of a park position is a major inconvenience for the average automotive user as well.

 

Thanks for the input guys. I guess I can check on my gearing options with the older models and decide which way to go. Lockup may not be necessary in my case but it's something I would like to have.

Length is going to be an issue. I am not sure about overall size comparison between my t-19 and the allisons. Not much drive line room in my Bronco so if anybody has an idea let me know.

 

You can look into a ranger torque splitter. They sell them at Jeff's Bronco Graveyard. They allow you to split every gear and give you a 27% overdrive. They bolt between the bell and the trans and are about 7" long. I plan to get one myself when the money is there.

 

Your looking Allison at545 out of a s-series international

 

Well the only time I ever had any success is when my '05 D/A broke down. Trusty 'ole black did a fantastic job with that allison behind her!!!!!!!! ROFLMFAO!

 

I will have to look into that. I have considered an overdrive but my biggest concern has been drive line room. If I could I would have 6 speed auto and an overdrive. Little much? Maybe. So far I haven't seen an example of a 6.9 with an even reasonable overdrive gear so what kind of RPM drop it can handle is something I would like to see.

Off the subject. How are the ARP studs working out for you? Ever have to re-torque?

 

Range torque spliters only work with older 4 speed manual trans. Don't think it'd work with a C6 or E4OD. Gear vendors spliters on the other hand will work with auto's.

 

So far the studs are doing great (no retorque yet). As for the torque splitter he could swap out to the 4 speed and the splitter cheaper than the other way I would think. I picked up a good used fly wheel and bell housing at a u pull for $100. A gasser 4 speed will work fine and are plentiful. It also gives a lot lower 1st gear when you need it. The torque splitter also allows you to run with the over drive in 4x4 if needed. I called jeffs bronco grave yard and they told me that it fits in to the driveline well.

 

So what you just need the diesel bellhousing? Then could use a gas/diesel 4 speed? Oh that's pretty cool then. Will have to keep that in mind if this new e4od takes a crap on me.

 

Yes, I am running a gasser t18 out of a 80 Bronco in mine right now. I love the lower granny gear of the gassers.

 

I'm glad I put on studs. I had 4 broken bolts I had to take out before rebuild. Stretching......re-torquing......stretching. Not good.
That's one thing I like about these standards is switching out the bell housing. Nothing like having more options.