SAE #3 vs GM Bellhousing

[Scholioso]

Alright guys. This question stems from my 96 chevy k3500 12v cummins swap. Right now I'm running a 4l80e behind it & its handling it, but I'm prepping for the future. I want to swap a 6 speed ally in it.

Looking online, I found a company called Howard's conversions that will allow me to adapt the ally to the cummins. It utilizes the dodge automatic adapter plate, flexplate, & starter. This is beneficial to me for a few reasons.

1) as of right now, the 4l80e adapter plate locates the starter to the passenger side. This makes exhaust clearance extremely tight. The dodge automatics have the starter on the driver side. This frees up space for the exhaust

2) the engine sits closer to the passenger side frame rail than the driver side right now. Again, the dodge adapter plate locates the starter to the driver side where there is plenty of wasted space as of now.

3) it's cheaper than other adapter plates

4) since I would be using a dodge starter & flexplate, parts arent custom, & therefore much cheaper if I needed to replace them as compared to buying a custom adapter plate, custom flex plate, etc

So with all this, my biggest concern is size as space is relatively limited. I'm not familiar with sae bellhousing sizes. I'm curious to know if the sae #3 bellhousing is bigger than the GM bellhousing? Does anyone by chance know? Thanks for the help!

 

[THEFERMANATOR]

If you're going to run an sae #3, just get an allison from a 4500/5500 kodiak or other medium duty truck, and run the Cummins sae #3 parts.

 

[Scholioso]

Is the allison out of those the same model? Those are more work trucks & towing vehicles over go fast pigs right? If they are different models, can they be modified to hold good power? I'll definitely look into getting one out of those trucks tho

 

[THEFERMANATOR]

The allison in the 4500/5500 kodiak was almost identical. About the only real difference between s GM allison 1000 and the other 1000's is GM used a smaller C5 piston in there version for the pickups, other than that they're the same so long as you don't get a 2000 series.

 

[Scholioso]

Ok. So theres a guy local to me selling an allison 2200 pts. Looking at the specs online, they all look identical to a 1000. He said that it was in a bus which had a duramax in it? Doesnt make much sense to me since it has a sae#3 adapter on it, but I dont know the medium duty stuff so he could be legit or he could be lying. He said he picked up the motor & trans together & it was bolted to a duramax. It's a 2wd setup with a parking brake on the driveshaft.

Serial number:
6310851122

Thoughts?

 

[Rockabillyrat]

The medium duty Allison's run the SAE housing and a different C5 assembly for the larger yoke. And the only difference between a 1000 and 2000 are the gear ratios. I do conversions at work. I run a medium duty operation system in the TCM with a TPS sensor to control them. Gear ratios can be changed with EFI live. So you can take any combination of allisons and make it work tuning whise. I used parts off a 2000 to convert a 1000 to medium duty on a f800 project. I swapped out the 545 because the compounds where to much for that transmission.

 

[Scholioso]

Oh ok. So this 2200 pts sounds like it's what I need. Online says theres no pto on these? Which is ok. I can live without it. Would have been cool to mount an air pump on it & have on board air tho.

Either way, I still have some questions:
1) how do I verify if this trans has a park pawl or not?
2) how does the parking brake on the driveshaft work?
3) how hard would it be to convert this trans to a 4wd?
4) how much bigger is the sae3 bellhousing compared to the standard gm?
5) what tcm do ya'll recommend?

My chummins is running good with the 4l80e, but I think I cut a seal when installing the torque converter. Shes been puking tranny fluid everywhere & I can't pinpoint the source. If I have to remove the trans again, I'd rather just swap it for this ally.

 

[Rockabillyrat]

I would find a 4wd allison 1000 from a Chevy and swap to the SAE bellhousing. The other options are finding a 2000 and swapping the c5 and tail housing to 4wd.

I should clarify a 5 speed allison can be set up to run as a standalone transmission. All you need to do is run a medium duty operating system on the 5 speed TCM. Then add three wires for a TPS sensor. A 6 speed allison will require a PCS controller to make it work.

Allison 2000s don't have a parking paw. The 1000s do. So if it has the big yoke then no park paw. That all in the C5. Thats the difference between the two and why the gear ratios are different. The parking brake on the drive shaft is and auto park system found on alot of RVs. I would just get a parking paw allison. Save your self the extra work.

 

[Rockabillyrat]

The f800 I did had a 12v in it. The bellhouing adapter, flywheel and flywheel spacer bolted right up from the 545. We made a billet spacer to handle the torque from the built 12v though.

 

[Scholioso]

Here's why I was wondering if it does or doesnt have a park pawl. Hopefully these screenshots are good & clear for ya'll.
On the second page it says the 2200 series have a parking pawl? If it has one, I think I might go pick it up. He said he would let it go for $600. Can't really beat that price. That's torque converter, adapter plate from duramax to sae3, flexplate, etc.
I

 

[Rockabillyrat]

I forgot the 2200 does have a park paw. But you will need to get the internal parts and tail housing to convert it to 4wd.

 

[Scholioso]

I wonder how hard that would be to find. The cheapest sae 3 housing I can find is around $200. So the cost of a 6 speed around $1500 plus the bellhousing puts me at $1700. Whereas this one is $600, that gives me an $1100 buffer to find the parts to make it 4wd. If that's all I have to change, I think it could be worth it.

Looking at those pictures I attached earlier, the gear ratios appear to be the same as an allison 1000. And if it was behind a duramax to begin with, I see no reason why it wouldn't be.

 

[Rockabillyrat]

That $600 trans is worth it. You can use the bellhousing , torque converter, and spacer. You just need the adapter and flywheel for the Cummins to work with it.

As far as the 4wd conversion. The 2wd allison has the output speed sensor in the tail shaft. The 4wd version has it in the transfer case. So the easiest way is to get a 4wd allison 1000 tail shaft housing, c5 apply piston, tail shaft and p3 planetary. That will convert it to 4wd. Then you can run the gm transfer case with the correct 40 tooth tone wheel. That will keep the TCM happy.

Depending on what planetary the 2200 uses you might have to change your gear ratios with efi live in your TCM. I don't remember what the tail end of those use as far as parts.

 

[Rockabillyrat]

Sorry I missed the part you said about the gear ratios. If they are the same the p3 should be the same then. You might only need the 4wd tail shaft and not the whole planetary.

 

[Scholioso]

Idk if they are. I'm going to call Allison tomorrow & see what they say. Cuz if they are, then I think I'm set. I think with the $1100 savings difference, I can possibly find the 4wd parts & maybe even rebuild it. Going to call a few different transmission rebuilds around here & see about getting the 4wd tail housing & output shaft.

Do ya'll think that torque converter would be okay to run? I guess it has a stall ratio of 1.73. Heres the allison decoding from which I'm cross referencing with the attached screenshots from above.

 

[Rockabillyrat]

Download a copy of the ATSG allison manual. It will tell you everything you need to know about the gear ratios and internal parts. I have a paper back copy I refer to on rebuilds a trouble shooting issues.

Allison's are extremely easy to rebuild. Only need a few tools to do it. I would contact suncoast about a rebuild kit and converter. All Allison's share the same p1 and p2. The p3 is what changes the gear ratio between the two. If the 2200 has a park paw and the same ratio as a 1000 then they should share the same planetary. If that's the case that's probably the best trans to get for your swap. The ATSG manual should have that info in it. Mines at work at the moment or I'd check.

 

[THEFERMANATOR]

I should clarify a 5 speed allison can be set up to run as a standalone transmission. All you need to do is run a medium duty operating system on the 5 speed TCM. Then add three wires for a TPS sensor. A 6 speed allison will require a PCS controller to make it work.

This is not true about the 6 speeds. Theres several 6 speeds running around with a tps hooked up to the a40 running a gm calibration working fine. In the absence of the high speed lan signal, it will default to the hard wired tps.

 

[Scholioso]

So from what I understand, to run a 6 speed trans as a standalone, I need an A40 TCM & wiring harness? Anything else? Will it need a custom tune? The 12v cummins has a TPS on the injection pump already so hopefully I can make that work. I was really hoping to use my BW 4401 T-case with the allison, but it sounds like I wont be able to do that since the allison is a 29 spline & the 4401 tcase is a 32 spline? And as far as I know, there aren't 32 spline output shafts for Allison's that I'm aware of.

 

[Rockabillyrat]

This is not true about the 6 speeds. Theres several 6 speeds running around with a tps hooked up to the a40 running a gm calibration working fine. In the absence of the high speed lan signal, it will default to the hard wired tps.

Good to know about the 6 speeds. Thanks for the info.

So from what I understand, to run a 6 speed trans as a standalone, I need an A40 TCM & wiring harness? Anything else? Will it need a custom tune? The 12v cummins has a TPS on the injection pump already so hopefully I can make that work. I was really hoping to use my BW 4401 T-case with the allison, but it sounds like I wont be able to do that since the allison is a 29 spline & the 4401 tcase is a 32 spline? And as far as I know, there aren't 32 spline output shafts for Allison's that I'm aware of.

You need the correct TPS voltage input to the TCM. I always use the factory allison TPS on the few I've done. But if your Cummins sensor can be a adjusted to give the correct closed and WOT voltage values it can work.

Again 4wd Allison's have the output speed sensor in the transfer case. It's a 40 tooth tone wheel. You must give the TCM the correct wave pattern for it to be happy. Other wise it will go into limp in mode. The correct GM transfer case is the way to go in my opinion.

 

[THEFERMANATOR]

To my knowledge they all used the ALLISON TPS for the 6 speeds. I believe they used the 8.1L tune in the A40 TCM for them since it used J1850 and J1939 instead of only GM high speed LAN. There is somebody making 32 spline output shafts for the ALLISON to make it easier to run the np205 transfer case for right hand drops since the 29 spline input is so hard to find for them. I don't remember who it was, but I seen it on the duramax engine swap group on facebook.