allison swap

Forrest Nearing said:
there's a reason Duramax guys swap 47/48 trannies in their trucks, and it's not because the Allison is better
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Most of them say the gear ratio in the Allisons are better but the 47/48 hold up better at the higher hp level.
 
My truck is sitting at my brothers house right now with the fourth dodge transmission out and sold. I tow ten thousand all the time cross country and lost three built transmissions. Each with less than thirty thousand on them. fully built Allison is sitting in the garage waiting for the adapters (were supposed to be here last week). total cost with a brand new 271 transfer case, electronics, and drive line mods should come in around 6600- 3200 for the old transfer case and transmission. Out of pocket 3400+400 for shipping. everything is New so I think its worth it.....Would I do it again we'll see.


I talked to a guy who did this and he said its a different truck. You step on the gas and it just moves right now. The converter locks up in all forward gears except first.

There is know way that the dodge transmission is stronger then these. These are put into 35000 lb buses and trucks, with little issue, the reason the chevy guys have problems with them is programing. these transmissions are 100% computer controlled and if its not set up right with the right load and power they wont last. I was doing some reading on them in the heavy duty applications and they seem to last several hundred thousand miles......Its all about the programing and set up.

They will not shift as fast as a dodge because their internal parts are massive. More mass = slower shifts, not what you want for racing.....But I'll take it for towing.

List of builders for my dodge transmission are as follows
Myself with dunright parts
Michael, Hot Rod Diesel
Walters Transmission, Twice
All rebuilds were using the dunright, goerend system, Problem finally figured out as a pressure regulator valve sticking when trans got hot.
Total invested on rebuilds 8600 plus towing... I was finished....
 
built 47/48 with a gear vendors. an allison is a big trans, weighs more, and is gonna take a little more power to turn it.
 
I ment to hit 4 speed earlier I check this on my phone at work and the screen is small and my fingers big I didn't meandering to say 3 speed
 
I have done numerous allison swaps into 12, 24 valves, and cr trucks. There is no comparison to a 47. If you are planning to drag race then I would say go with a 47. If you want a all around truck for towing, driving around and some dragging, then go with a allison. Allisons are alot stronger in stock form then a pretty well built 47. Allisons will shift just about as fast as a 47. Most people think they are slow shifting b/c they see them in the duramax trucks that defuel during each shift which makes them shift slower. I have a few customers that would be more than happy to talk to you and they can give you their honest opinion. I had a 12 valve that was 750hp and only ran a stage 3 allison and I sled pulled with it. I tore it down every year just to look it over and never replaced anything inside. It still looked brand new. That is just my 2 cents.
 
In my opinion the allison is better for daily driving and the 47 can get it done on the track. For all around use I would take my 6spd allison over any 47 no matter how its built. The only reason Dmax guys spend the 12K to swap over to the 47 is to have the much less complicated shifting of the older style transmission. The allison is very complicated and to get it to make perfectly timed shifts when running 9's or faster would almost take an act of god. In my opinion the allison is far superior to the 47 unless your running 9's or faster in a dedicated drag truck that needs fast shifts, now if you can figure out how to time the shifts just right for the allison then you could probably make it work at those times also.
 
I've been thinking about putting an Allison behind my new 6.7 motor. The lower first gear would allow me to make less smoke with the 13mm p-pump and driveability is the main goal. Going from the nv5600 to the 47rh was bittersweet. I love the automatic, but I miss the extra gears and ability to get the truck moving easier.
 
bwdt said:
My truck is sitting at my brothers house right now with the fourth dodge transmission out and sold. I tow ten thousand all the time cross country and lost three built transmissions. Each with less than thirty thousand on them. fully built Allison is sitting in the garage waiting for the adapters (were supposed to be here last week). total cost with a brand new 271 transfer case, electronics, and drive line mods should come in around 6600- 3200 for the old transfer case and transmission. Out of pocket 3400+400 for shipping. everything is New so I think its worth it.....Would I do it again we'll see.


I talked to a guy who did this and he said its a different truck. You step on the gas and it just moves right now. The converter locks up in all forward gears except first.

There is know way that the dodge transmission is stronger then these. These are put into 35000 lb buses and trucks, with little issue, the reason the chevy guys have problems with them is programing. these transmissions are 100% computer controlled and if its not set up right with the right load and power they wont last. I was doing some reading on them in the heavy duty applications and they seem to last several hundred thousand miles......Its all about the programing and set up.

They will not shift as fast as a dodge because their internal parts are massive. More mass = slower shifts, not what you want for racing.....But I'll take it for towing.

List of builders for my dodge transmission are as follows
Myself with dunright parts
Michael, Hot Rod Diesel
Walters Transmission, Twice
All rebuilds were using the dunright, goerend system, Problem finally figured out as a pressure regulator valve sticking when trans got hot.
Total invested on rebuilds 8600 plus towing... I was finished....
Click to expand...

Have to agree with you. I have had the best money can buy built Allisons and duraflite. For drag racing with big HP, the duraflite is great in a dmax. It's a dumb transmission and shifts when you tell it to. It's 100 lbs lighter and doesn't have the shaft snapping issues behind the damx it does with the cummins due to the torque of the cummins. you can for the most part program around that with the dmax. We had our first duraflite in Max'd Out since we first started racing the truck last year with no issues at all, (knock on wood), we do have to change out the TC about every 30 passes or so.

The computer in the allison is the problem, too damn smart for it's own good. Has a tendency to freak out and lock up when it sees something it's not use to. Shifts are much slower than a Duraflite. For towing the 6 speed allison is a great tranny, has manual bump shift and damn near idiot proof for towing. I know there are several guys who have put an Allsion behind their cummins for pulling. I can't comment on how they have done because I don't follow pulling too close.
 
I am putting a Allison in my 12v right now,I loved the NV45 an Iron giant for sled pulling but driving around town was not much fun.I went with Allison because I have seen to many dodge auto's go out while sled pulling an I have seen for my self the allison last pull after pull with no problems,but yes if I was drag racing I would have went with the dodge auto.
 
I will be using the Fleece controller or the Destroked controller
 
I got all my stuff coming for the swap but what are you guys doing for a crossmember? anyone have any pics ?
 
Any updates on this?

I'm considering an Allison for my 12V as well.
 
destroked said all you have to do is make a spacer about 1.125 inches high to hold the transmission at the right angle. will know in a week when the trans is in.
 
Latest update. I was unable to get the parts from Howards. I have hired a shop to make an adapter plate for the converter and the transmission. he has all the measurements and will start them on Monday. He will be making several sets if anyone is interested. They are being made from billet aluminum and steel. I hope to have them by Friday next week. This system should be cheaper then a full sae system and you can use the standard cross member.
 
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