Allison 6 speed transmision?

[IH-GM IDI]

I've thought of doing this swap as well but with a 3000-4000 series sense they're easier to find the SAE 2 bellhousing that can typically still be found for our idi's.

We have 10 trucks running the 3500's behind 8.3 Cummins (325 horse tune) that typically operate at 35 to 45 thousand pounds. These units are super reliable and built to handle real work.

 

[Noiseydiesel]

I sent the Allison boys an email 2 days ago. No answer. IF I buy a new(er) truck, it will probably be running a 10 speed trans and what not. I figure that Allison will give me the two missing gears that I am in search of.
Bottom of the truck already has enough going on with changing over to Super Duty springs and a 4X4 swap.
Not going to be looking at a Gear Vendor. If I get the 4X, springs and brakes upgraded, that should keep me happy enough for some time.

 

[Blue94]

Don’t like the Allison behind our dt466e at all. IH locked out the extra gear they used in heavier model trucks and no overdrive eats fuel when loaded, would honestly rather have a well built e40d behind the IDI with a trans controller.

I think the 6sp 1000 series has 2 OD gears, I talked to Allison in Indy and they would only allow with 1 OD Gear with the custom program and the stand alone controller. I bet that 466e has a 3500 series trans that only had 1 OD to start with, I could be wrong though. That’s the drive train one of our bucket trucks has, it has the OD intact and does very well actually. We have that same 3500 Allison behind an 8.1 bb Chevy in a smaller truck, there is not much help for it, factory governored to 65 mph (municipality ordered) and gets 6-7 mpg no matter how it’s driven

 

[jrollf]

I get the impression from CA Conversions website that their custom controller allows the use of all 6 gears. The 6 speed does have two overdrive gears.

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[IDIBRONCO]

and gets 6-7 mpg no matter how it’s driven

This is why we love our diesels.

 

[IH-GM IDI]

All the 6 speeds should be double overdrive .75 for 5th .65 for 6th.

 

[Fision]

All the 6 speeds should be double overdrive .75 for 5th .65 for 6th.

yup, those are the D.O. ratios. There are a few slight variances, but basically this is it. The 1000, 2000, 3000 and 4000 series ALL have at least 6 gears (a few have a super low granny 7th gear, like the md3070). Many have been electronically limited to 5 speeds, which is a function of the external Transmission Control Module. Some of the early 1000 series also had a 5-sp valve body, so that would need to be changed along with the programming. But there are ways to unlock the 6th gear. There’s an extensive thread on skoolie.com called “Md3060 unlock tutorial” that goes into it.
I got the 6th unlocked in my ‘95 IH 4900. Haven’t seen a change in mpg. Prob because I go faster now

I do share Wes’ frustration with the 6th gear lockout. VERY frustrating experience trying to get it unlocked. At best, it’s an inconvenient pita. At worst it’s an expensive, time consuming pita- or a dead end for those who don’t persist.
It can be done, but it will be a pita.

 

[Fision]

And what about the 6-sp ford has behind the 6.7 PS? My understanding is that this is quite a bit tougher than the 1000 series Allison in stock form. Is there anything to physically mate it to the idi, and how would shifting be controlled??
Just a thought...

 

[DaveBen]

Computer controlled.

 

[Fision]

Computer controlled.

Yes. As are the Allison’s, unless you go back to the old 4 or 5 speed non-OD models like the at545 or mt643/mt653.
To clarify my question,
1) does the stuff exist to adapt the Ford 6R-140 controls to our engine? Or is a standalone controller available?
2) what about bell housing/physical interface?
The 6R-140 can take 1000+ft/lbs of torque. That’s a lot more than the stock Allison 1k or 2k series.
Obviously the 10R-140 would be better yet, but would prob cost more than our trucks until it becomes more common.

and to the OP, I hope this isn’t considered hijacking your original question. You did specifically ask about Allisons, but your explanation of frustrations with your current setup points to simply wanting a satisfactory solution, whatever the flavor.
I apologize if I’m wrong in that.

 

[jrollf]

No problem, I'm always up for a good discussion on alternatives.

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[trackspeeder]

Yes. As are the Allison’s, unless you go back to the old 4 or 5 speed non-OD models like the at545 or mt643/mt653.
To clarify my question,
1) does the stuff exist to adapt the Ford 6R-140 controls to our engine? Or is a standalone controller available?
2) what about bell housing/physical interface?
The 6R-140 can take 1000+ft/lbs of torque. That’s a lot more than the stock Allison 1k or 2k series.
Obviously the 10R-140 would be better yet, but would prob cost more than our trucks until it becomes more common.

and to the OP, I hope this isn’t considered hijacking your original question. You did specifically ask about Allisons, but your explanation of frustrations with your current setup points to simply wanting a satisfactory solution, whatever the flavor.
I apologize if I’m wrong in that.

There is no controller available for the 6R140 yet, that I know of.

You will need a custom flexplate and adapter plate. Plus some $$$$.

 

[IH-GM IDI]

Both options are going to be $$$
The allison will need the international sae2 or 3 flywheel housing with matching adapter flywheel (not flexplate). A big external cooler (usually water/oil cooler). A means to down size the driveshaft. Probably need a body lift and some firewall massaging, a custom crossmember, and a batch of other modification and fab work to get everything setup right.
After that you also need to have the TCM programmed (if you have a allison dealer nearby they should be able to do this) how you want it and insure you have the correct speed stall on the torque converter (there's a whole batch allison makes for this) to benefit your pump/turbo setup.

 

[Garbage_Mechan]

Both options are going to be $$$
The allison will need the international sae2 or 3 flywheel housing with matching adapter flywheel (not flexplate). A big external cooler (usually water/oil cooler). A means to down size the driveshaft. Probably need a body lift and some firewall massaging, a custom crossmember, and a batch of other modification and fab work to get everything setup right.
After that you also need to have the TCM programmed (if you have a allison dealer nearby they should be able to do this) how you want it and insure you have the correct speed stall on the torque converter (there's a whole batch allison makes for this) to benefit your pump/turbo setup.

I believe the conversions are getting done by converting the back of the engine to a Duramax pattern then running that bell housing on the trans. No giant SAE pattern.

 

[Garbage_Mechan]

I have been working with Allison transmissions for garbage fleets since 1978. In that time I have spec’d 100’s of new trucks. Allison has a program called SCAAN that verifies speed in gears, shift points, grade climbing ability, ability to start a load etc. I never built a slug. Garbage Equiment is in a drag race all day long!