Yank Tank Molotov/3+3, 454/magnum/Allison

[SpeedlabDan]

So I had a long conversation with Dave from CA Conversions. Very knowledgeable guy. So we went back and forth and the Allison will be easily adapted and he offers a stand alone tcm for it. My issue comes back to the vss as before with the 8.1.

See, when we use our np 205 tcases we have the tone wheel modification and the hall effect vss done by ORD. This puts the vss after the tcase and while it's good for the speedometer it is not for the transmission controller and will put the trans in limp.

So round and round we go and basically I can't use the Allison with the magnum box. I need my vss before the gear reduction.

Dave offers a coupler housing that will adapt the tcase but it only works with the dodge 29 spline np205. This housing is also only 3" thick opposed to the 6.25" of the magnum.

I'm trying to be cheap and lazy so I didn't want to move the location of the tcase and have my driveshafts rebuilt. I may not be so lucky but the Cummins may shift the trans back 3-4" so that I may be able to work with.

Of course I could just use the old np263 or whatever it is that came on the Allison but I'd have to find that illusive '73 Ford dana60 with the passenger side input and correct spring width....

 

[Fastereddie]

The Allison doesn’t generate a vss signal?

 

[Truckman4life]

Did some googleing and found a thread on pirate where Ian talked about what he did on the suburban gorilla project. It had a dmax and allison with a doubler/205. He said he did a custom tone ring on the Trans output and drilled and tapped the rear of the Trans to mount the sensor there. Adavance Adapters has what I believe to be a vss relocation kit to do allison to 205 with the sensor in it but there's no info on their site about it.

Allison to NP205

Hey All, I am currently working on building/designing a truck and am hung up on finding a suitable transfer case at the moment. I am running an Allison 1000 transmission and would like to know if any one has advice on adapting a NP205 in a married configuration. I have heard that a ford...

www.pirate4x4.com

 

[SpeedlabDan]

That's an option but that's gonna add another 2 inches or so to a drivetrain that's already barely going to fit. I'll have to do some digging

 

[K30guy]

Not to derail but to add info.
There is a slightly better than snowballs chance in hell I could end up with this. Good, bad, ugly?

Could be a big job to make that thing suitable for a pick up truck. That Stanadyne pump is an oddity, but it looks like it's the same pattern for a Ve pump. If the rotating gear is good and the price is cheap, I'd pick it up and stick it in the corner of a shop until I found a blown 12 valve with all the accessories to swap over. Neat colour, too

 

[ZooMad75]

Something don't make sense here. Factory 4wd GM trucks with Allison trans use the vss output in the t-case exclusively. It's why the 4wd version does not have a VSS output in the transmission in the first place. The TCM uses input from the T-case control module to know that the t-case is in low range. With that input coming in, when it sees 4lo the TCM makes the needed adjustments to account for the added gear reduction after the transmission.

Sure having the VSS installed before the t-case will give it a solid value, but the issue still comes in when you drop into low range on the magnum or the t-case. That's when the TCM is going to flip out. I would question if the conversion guy has the ability to take a signal of a low range input from the t-case and have it make the needed adjustments.

Just doing a little Google-fu on the subject netted a ton of stuff regarding exactly what you are trying to do. Much like LS swaps are old hat now the Allison/6bt/4bt swap is fairly common. A thread on a 4btswap site had a ton of good info, including dealing with using a 205, doubler and how to address it.

The complete Allison 1000/2000/2400 info and swap guide...

I decided to start a thread devoted to this trans for a couple reasons. First off, there is a LOT, and I mean a LOT of misinformation out there. Second, there is little useful info for some basic specifications on these transmissions. Finally, a lot of guys think they are too complicated or too...

www.4btswaps.com

 

[sweetk30]

but @ZooMad75 if your running a non stock ratio t-case AND doubler the stock ecm is not setup for this so lots of guys run the trans swaps as 2wd and deal with the rest so the trans is happy . this might be my guess as to why the swap kit he was posting and talking about .

 

[ZooMad75]

but @ZooMad75 if your running a non stock ratio t-case AND doubler the stock ecm is not setup for this so lots of guys run the trans swaps as 2wd and deal with the rest so the trans is happy . this might be my guess as to why the swap kit he was posting and talking about .

Why go half-assed though? If you read further into the thread on 4btswaps they get into the programming side for a non-stock 203/205 doubler. The point is stock setups use the t-case vss location and adjust based on the input for 4lo. Why the hell would anybody run the vss in front of the t-case to only have the trans freak out when you pull the t-case lever into low range? Might be fine for the average bro-dozer that never actually uses 4wd but I'm going to take a wild guess that if somebody (Dan) invested in a friggen magnum box he's probably inclined to actually use low range in it and the 205. Why not make it work right in low range as it does in high range or 2wd?

@mrk5 and @AgDieseler both run standalone 4L80e's with magnum boxes and each has the ability to deal with the low range and doubler. Before anybody whines and says but hey those are 4L80e's that don't compare to an Allison, it's all just inputs and outputs. A standalone setup isn't always running a modified stock TCM. So if the companies that figured out how to do it with a 4L80e certainly makes one think it could be done on an Allison.

 

[sweetk30]

but a magnum is 2.72:1 ratio over a 203/205 combo .

yes i didnt read the WHOLE tread you linked but i am shure it is packed with info . this was just my quick take on the setup .

 

[ZooMad75]

but a magnum is 2.72:1 ratio over a 203/205 combo .

yes i didnt read the WHOLE tread you linked but i am shure it is packed with info . this was just my quick take on the setup .

2.72:1, 4.0:1 or 1.96:1 it don't matter. If the TCM/standalone module has the ability to adjust, you just plug in the number.

 

[cheavyk10]

Dang, all these complications would make me want to run a manual...
Just saying
How would a SM465 be behind a Cummins?

 

[6872xtc]

Dang, all these complications would make me want to run a manual...
Just saying
How would a SM465 be behind a Cummins?

The gear splits still suck.
And if the axle ratio is not good, well crappy launch from stop or terrible top end.

 

[AgDieseler]

2.72:1, 4.0:1 or 1.96:1 it don't matter. If the TCM/standalone module has the ability to adjust, you just plug in the number.

Preach. Better living through shift tables.

David

 

[K30guy]

Dang, all these complications would make me want to run a manual...
Just saying
How would a SM465 be behind a Cummins?

Almost undrivable in stock form, honestly. The low ratios and no overdrive coupled with an engine that redlines at 2700 rpm makes for a bad time. A 465 with a gear vendors, though, could be a neat combination

 

[ZooMad75]

Almost undrivable in stock form, honestly. The low ratios and no overdrive coupled with an engine that redlines at 2700 rpm makes for a bad time. A 465 with a gear vendors, though, could be a neat combination

I think the suggestion to a 465 was sarcastic guys... Just a guess.

4500/5600 or ZF6 all are better suited if one wanted to row gears with a 12v.

Blech, I'm talking diesel. I think I threw up in my mouth a little.

 

[SpeedlabDan]

So here we go Finally back to work I cleaned the totes of parts out of the back seat and briefly rummaged. Turns out the th400was overhauled and the np205 was replaced. (Who replaces a no205?) and I have all the interior trim and spare parts. If you know you know, these interior parts are hard to track down for a crew cab/suburban. Also a cast aluminum dust cover for the th400. I’ve never had one of them before.
So off to a good start I started organizing the cut wires under the hood and I’ll have to track down the fuel pump wiring. I’m not sure yet if the pump has been bastardized to only run the one tank or if the switch is still functioning. The green wire in the one pic is (keyed on) but cut and stripped and seems to be too small gauge to be the power feed but maybe just a signal. I’m trying to keep the wiring as correct as possible for obvious reasons.
Anyone have a clue to what the connector in the last pic is for?

 

[SpeedlabDan]

Also that final pic is with the “alloyworks” 4row aluminum radiator, the first thing I’ve bought and it seems pretty good. Trouble is the rubbers don’t sit where the tanks are but where the sharp channel of the core reside. I’ll have to fab up some better fitting rubber mounts.
And a touch of speed lab for ok Betty, my 6” k&n aircleaner off the k5

 

[SpeedlabDan]

I also believe the other pic of cut wires may be the factory cruise control but I’ve never had one complete so it’s a guess. There’s gonna be a lot of testing on the goofy stuff I find

 

[Truckman4life]

You'll probably need these if you don't have them already. Top schematic is cruise control and bottom is fuel pump relay if that helps also.

1973-87(91) Factory GM Pickup Manuals

1973-87(91) Factory GM Pickup Manuals

forum.73-87chevytrucks.com

 

[SpeedlabDan]

You'll probably need these if you don't have them already. Top schematic is cruise control and bottom is fuel pump relay if that helps also.

1973-87(91) Factory GM Pickup Manuals

1973-87(91) Factory GM Pickup Manuals

forum.73-87chevytrucks.com

View attachment 415114
View attachment 415115

Right on I had them saved on my android phone but just switched phones I definitely need the fuel pumps but I’d like to lock down the others bare wires in the bay, thanks man