Best auto trans for Cummins?
 

What's the best option for putting an auto trans w/OD behind a Cummins? Is the 4L80E an option? It would be for a 4x4.

Re: Best auto trans for Cummins?
 

It depends how much money you want to spend and how you want it to drive. Buying an adapter and trans controller for the 4L80E will run from $2000-$2500 depending who you get it from. The trans will need a heavier torque converter, and at least a good rebuild minimu. You can use a dodge 47rh and the over drive and lock up can be controlled by a dodge pcm, toggle switches, or pressure switches. You can use the dodge engine adapter and flex plate so cost there is less. The trans will need a heavier duty torque converter as well, and a rebuild. You'd need a tcase with a 23 spline input to work with the dodge trans as well. So, it really just depends on what you want to spend and such.

Re: Best auto trans for Cummins?
 

I'd use a NP205 with this adapter:

http://www.advanceadapters.com/produ...h350-or-sm465/

700R4 would probably be a bad choice for a Cummins.

Re: Best auto trans for Cummins?
 

Yes, I doubt a 700R4 would last long without a couple thousand thrown at it and then I bet it still wouldn't last a long time behind a healthy cummins.

Re: Best auto trans for Cummins?
 

Would it be easier to use a 6.2 or 6.5 with a 4L80E?

Re: Best auto trans for Cummins?
 

1972K20 - I am running a 4L80 behind a 24 Valve VP that is stock and a NP205 TC. I only have a little over 200 miles on it so far but it seems to work nice so far. I still haven't pulled anything with it because I need to put a GN hitch in it first. My 4L80 is all stock and I was told it came out of diesel suburban. You have to rev it up a little more than I am used to when you take off from a stop but it shifts smooth.

Re: Best auto trans for Cummins?
 

It definitely would be easier, but why? Then you're sitting on a grenade that has less power than a 4bt. :lol:

Re: Best auto trans for Cummins?
 

How did you set it up?

Did you use anything like this:

http://www.transmissioncenter.org/cu...bt_adapter.htm

Re: Best auto trans for Cummins?
 

Haha...yea, well, I'm trying to explore different options. My main goal was to have a 4spd auto w/OD and a 12v Cummins. I prefer the 4l80. However, I do want to keep cost at a minimum. I've thought about the 6.5. I know they don't compare to the Cummins, but I've heard the 1999 and newer 6.5 have a lot less problems than older 6.5s

Re: Best auto trans for Cummins?
 

Yes, I had to purchase the transmission adapter, flex plate, new starter, PCS transmission controller, I had to get a spacer to connect the Trans to the NP205, and run a transmission cooler. The Dodge Cummins radiator lacks the transmission cooler connections. My PCS transmission controller has to be hooked up to a computer to change the settings but they make one with adjustment settings on the controller itself. It's definitely not cheap.

Re: Best auto trans for Cummins?
 

What makes the 4l80 your preference? i agree that they are good transmissions. but given the engine choice, why not use something that bolted up to it? GM didnt even try using the 4l80 behind a diesel that actually made power. they stepped up to the 1000 series Allison. If you run the dodge tranny, you have an oem combination that you can order parts for easily and dont need to buy any high dollar aftermarket goodies to run. since you will be saving that cash, you could easily toss it at the 47rh/re and make it a really manly trans that will last for years.

so, in answer to your question, the best trans is a 47rh. after that would be 47re. once you get past those two, you are looking at controllers or adapters to use any of the other available transmission options that will handle the Cummins.

Re: Best auto trans for Cummins?
 

Ford 5R110, I have a few customers running around at 500 hp with NO mods other than a good torque converter.

Allison 1000 6 speed, They do very well at 350/650.

47RE/48RE...Last a long time at stock power levels, The easiest & most cost effective solution.

4L80E's are not suitable for diesel applications, Even behind 6.5L's they seem to fail often, The Duramax in fullsize vans.....Though detuned still tears them up.

Re: Best auto trans for Cummins?
 

I definitely agree with you. I wanted to go with the 4l80 because of its strength/reputation and its GM. I'm not very familiar with the 47rh or 47re.

Re: Best auto trans for Cummins?
 

With the 6.5/4L80E combo in stock form the 4L80E's still failed? I didn't think the 6.5 had enough torque.

The Allison's are too costly for me to consider, but that would be really cool though. Plus, they rob more power than most tranny's from what I've heard.

Re: Best auto trans for Cummins?
 

The 6.5L still has a tremendous amount of torque rise compared to a gas engine, producing 440 ft. lbs...Which is the torque limit of a 4L80E, A slightly warmed over Cummins will lay down over 600 ft. lbs.

Yes, A 4L80E can be built to handle it, But dollar for dollar....A built 47RE/48RE will last longer.

Allison 1000's are fairly efficient, The gear ratio spread is fantastic, A Duramax /Allison combo can knock down some impressive MPG figures.

Re: Best auto trans for Cummins?
 

I personally love the allison, but it's pricey to put behind a cummins. As for the the 4L80/85E, I've got a 4l85E behind a duramax in 2006 express 3500 cut away van with a 16' box with over 220,000 miles of heavy work behind it. We used that truck daily to haul barrels and drums of chemicals, often near or over max load for the chassis. Finally retired it to back up status and went to a 2.5 ton chassis truck. I've been more than pleased with how it has held up behind the detuned LBZ, which is rated at 250/460.

However, I think it's all about where the peak torque is and how you intend to use it. The cummins' peak torque and torque curve would be lower in the rpm range, which would definitely be harder on the trans. If you plan to hammer it a lot, I think even a built one would struggle to live, especially if you're fond of nailing it in overdrive.

The 47rh is a bolt on and the cummins guys seems to be able to make them live, so definitely the easiest option in my opinion, but I understand wanting to use a GM trans. I grew up staring at those stickers on the air cleaner that said "Keep your GM vehicle all GM, use only genuine AC Delco parts" and that has stuck with me. It's one of the main reasons I'm having trouble convincing myself to drop a cummins in my dually. I know it'd be easier and cheaper than the duramax/allison swap I'm planning, but I just can't convince myself to do it, LOL.

Re: Best auto trans for Cummins?
 

Dieselwrencher did the 47rh in the V-rig with np205 stock Dodge transfer case. Toggle switches for ovedrive and lockup. It works great. Tows 12k in my dump trailer with no problem with 354 gears 35 inch tires. Just some information, I know nothing about any other options.

Re: Best auto trans for Cummins?
 

The only down fall of the 5r is tuning to suit the user. Using a PCS isn't a great choisce by the end driver, but using the ford PCM and sniper or SCT for tuning is a lot better and you can keep tow haul mode.

Re: Best auto trans for Cummins?
 

You should think of it as fixing the truck the way you want it. I would care less to have a spark plug engine to tow even if it isn't a GM in a GM anymore. :lol:

Re: Best auto trans for Cummins?
 

I'm all for ditching spark plugs, my plans just include a couple more injectors :lol: I'm all for fixing a truck the way you want it and I've seen some sweet cummins builds.

Re: Best auto trans for Cummins?
 

On my crew cab, I had thought about an auto, and I have a 4L80 in the garage too. But I think I'm going with a manual. My first choice is a baby Road Ranger 10 speed. Yes I like rowing the gears. Plus I drove the big Rangers over the road. Plus with a manual, the wiring is a bit simpler.:lol:

Re: Best auto trans for Cummins?
 

I understand you said you want an auto but any auto that's worth using is going to require a tans controller which makes things in simple

So then maybe you could build a th400 and run a higher gear ratio to comp for the overdrive?

But to me a cummins just isn't the same without a manual.

Re: Best auto trans for Cummins?
 

This is a really good read, I'm in barking on a simular build. This should
become the bible of trans info.lol

Re: Best auto trans for Cummins?
 

Hey guys, I'm still moving forward with my build, or, should I say, collecting more parts..haha.

I have an Allison trans to go behind my 6bt. My question now is:

What's the most affordable and practical torque converter for this setup? It's a 6spd Allison from a 08 Duramax truck.

Re: Best auto trans for Cummins?
 

Affordable to me means buy one on sale and don't cheap out. Get one with a billet cover at minimum or you are going to be sorry IMO.