A3 Tranny in an A2

[fuzzytoaster]

Search has been exhausted so here it is, this came up in chat.

Since M35A3's were made from M35A2's would an A3's auto tranny fit in an A2? Discuss..

 

[nhdiesel]

There are 2 things to look at: 1. Will it fit in the truck? and 2. Will it attach to the engine?

1. Yes it will fit in the truck. as far as I know, the A3 has the same transfer case in the same location as the A2. They may use a different jackshaft, but that would be easy to cure. So the Allison should fit in place just fine.

2. I can't completely answer this one. The Allison will bolt up to the Multifuel's flywheel housing, they both share the SAE bolt pattern. But I'm not sure what is available to bolt the Allison's torque converter to the multifuel.

Jim

 

[fuzzytoaster]

There are 2 things to look at: 1. Will it fit in the truck? and 2. Will it attach to the engine?

1. Yes it will fit in the truck. as far as I know, the A3 has the same transfer case in the same location as the A2. They may use a different jackshaft, but that would be easy to cure. So the Allison should fit in place just fine.

2. I can't completely answer this one. The Allison will bolt up to the Multifuel's flywheel housing, they both share the SAE bolt pattern. But I'm not sure what is available to bolt the Allison's torque converter to the multifuel.

Jim

Thats what I had thought and am stumped on #2. I think this would be something to look into if not just for curiosity sake.

 

[nhdiesel]

There is a "but" I should have thrown in. Automatics have a large power loss factor. They consume power just to operate. Different autos have different efficiency levels, and the Allison really isn't all that bad, but it still reduces the power to the rear wheels. Ask someone who's driven both an A2 and an A3, and they will tell you the A3 seems pretty gutless. Now consider the A3 actually has a more powerful engine.

Next, autos just aren't a great match to a diesel because they like to be operated at fairly high RPMs and don't work well at low RPMs, where a diesel's torque comes on. Again, the Allison is better than most autos for this, but still not great. The result is the engine will be running at high revs all the time, which doesn't make great use of the available low end torque, and also wears the engine more than necessary. Why do at 2500 rpms, what you could do just as well at 1800?

Sorry, tossed my own opinions in there. I do like "what if..." questions though. While I don't care for autos behind diesels, I was considering putting an Allison behind my 12v Cummins when I wanted to swap it into the Grumman van to haul my Jeep. The only reasons were because the van would take a bit of engineering to set up with a clutch pedal and manual shifter. But the more I think about it, I think I would rather go through the effort and have it the way i want it...with a manual.

Anyone have a good 6 or 9 speed? lol

Jim

 

[jwaller]

you will get an increase in torque from an automatic. just try and race one from a stop light in your A2. they will smoke you.

 

[bulldog_mack13]

Yeah the A3 will smoke an A2. I burned all the A2 guys near me.

With the more powerfull Cat some of the power thats robbed by using the Auto is made up from using a better engine for the Allison. Id never do it but im curious also.

 

[Westech]

I have a valid question.....FT are you really going to do this swap? Seams to me that the cost of the trans and Controller and assorted parts would over come the cost of a A3 from GL. There are a lot of them that go for under 5K. You could sell your Junker deuce and buy a A3 and would come out ahead money, time, ect... Just my

 

[coolnick73]

On the flipside, could you put the A2's transmission into an A3?

 

[Westech]

that should be almost a bolt in.

 

[fuzzytoaster]

I have a valid question.....FT are you really going to do this swap? Seams to me that the cost of the trans and Controller and assorted parts would over come the cost of a A3 from GL. There are a lot of them that go for under 5K. You could sell your Junker deuce and buy a A3 and would come out ahead money, time, ect... Just my

If my research proves to be fruitful I would be happy to try in the future. My thought was to have a multi-fuel camper with an auto tranny, so basically a m109 with an auto tranny to make an "easy going" camper. Since M109A4's are uncommon at best and run about 7K thats a bit much for my taste. They also dont have multi-fiel capability obviously. The other option would be to buy an A3 and toss a 109 shell on the back but again..no multi-fuel capability.

What it comes down to, or what I see it does, is either swapping a tranny into a m109 or swap an engine and a shell on an A3 (Even starting at 5K would run high overall plus A3's are fugly).

Unless theres another suitable auto tranny for the A2..

 

[nhdiesel]

I'm not sure which model Allison the A3 uses, but you can get 4-speed versions very cheaply from an old school bus or other similar vehicle. I was offered one in excellent condition from a guy i know who owns a small bus company for $500. You can find them even cheaper if you look.

Jim

 

[TexAndy]

you will get an increase in torque from an automatic. just try and race one from a stop light in your A2. they will smoke you.

Actually, aren't automatics less efficient at transmitting power than manuals? Isn't there a certain amount of slippage in an automatic that's considered normal?

I don't doubt that the CAT diesel in an A3 provides more torque than the LDT-465... it's a more powerful engine. But an A3 accelerating from a stop faster than an A2 hardly proves the superiority of one or the other's transmission.

 

[ida34]

The torque converter acts as a torque multiplier. It provided more torque but is less efficient.

http://en.wikipedia.org/wiki/Torque_converter

 

[TexAndy]

The torque converter acts as a torque multiplier. It provided more torque but is less efficient.

Torque converter - Wikipedia, the free encyclopedia

Ah, that makes sense. Giant coupler that, in this case, provides additional gear reduction.

On an unrelated note, I wonder if anyone's tried to put an overdrive gear in an A3 auto transmission?

 

[lonegunman]

Ah, that makes sense. Giant coupler that, in this case, provides additional gear reduction.

On an unrelated note, I wonder if anyone's tried to put an overdrive gear in an A3 auto transmission?

Erik's military surplus has an A3 with an overdrive. My only concern from a 65 mph deuce is gear oil temps for the axels.

 

[tm america]

the question isnt so much if it will fit but more why would you want to put an a3 trans in an a2? the a3 uses a 3000-3200rpm rpm motor . While the multi only goes to 2600.In other word if you put an a3 trans in a a2 top speed would be about 42mph. Even if you put 46s on it top speed of about 50-52mph.Sure an a3 will dust an a2 up to 50 but the a2 will roll on by it from there.On a long trip the a2 will be so far ahead you wouldnt have to look at that ugly a3 front end in the mirror

 

[nhdiesel]

If you were to do an Allison, you would want the 1000 series, 6-speed with overdrive that GM uses behind the D-max. Now you are talking a lot more money, and a controller and wiring to operate it. These things are available, but costly. And if you are going that far and spending that much, you might as well get rid of the 134hp multifuel and swap to a modern diesel.

Its easy for a simple idea to escalate into a very costly and time consuming project, or else end up shot down because of feasibility issues.

I am one who will attempt just about anything that makes sense, even if it's only a little sense. I had a Volvo diesel (made by VW/Audi) hooked to a T-18 4-speed in a Jeep. I had a GM 2.8 V-6 in a Suzuki Samurai. Nobody else would ever want to swap that motor into anything, but it was a small, lightweight motor that put out 135hp. It replaced a 55hp engine. It matched the vehicle very well. I've done several automatic to standard conversions. I like thinking outside the box, its fun.

****, the vehicle I just had to finally retire was a 2000 Dodge Durango with a 3.9 4bt Cummins and NV4500 5-speed. Now I need a new home for the Cummins.

Jim

 

[Nonotagain]

the question isnt so much if it will fit but more why would you want to put an a3 trans in an a2? the a3 uses a 3000-3200rpm rpm motor . While the multi only goes to 2600.In other word if you put an a3 trans in a a2 top speed would be about 42mph. Even if you put 46s on it top speed of about 50-52mph.Sure an a3 will dust an a2 up to 50 but the a2 will roll on by it from there.On a long trip the a2 will be so far ahead you wouldnt have to look at that ugly a3 front end in the mirror

TM,

I don't know where you got the information from that the M35A3 Cat powered diesel engine was rated for 3,000-3200 rpm.

In the configuration received from Cat, the 3116 is only rated for 2,700 rpm

 

[coolnick73]

****, the vehicle I just had to finally retire was a 2000 Dodge Durango with a 3.9 4bt Cummins and NV4500 5-speed. Now I need a new home for the Cummins.

Jim

What happened to your Durango?

 

[tm america]

Man only 2700rpm that would give you a top speed of around 45mph if you put an a3 trans behind a multifuel with 9.00s on it. can you sayyy sssslllllooooooowwwwwww.Wow.