5.9 Cummins Motor Source

[1984CUCV]

I have thought about doing a cummins swap myself on more than one occassion and have done some research. I know a few have done it here with success. the main question is what type of transmission do you want use to get the end result you want. Can you use the th400- yes - but you would most likely have to have it rebuilt/beefed up and add an OD to handle the added torque. If you go the route of a manual shift - which is the way to go - you will have to spend some $$$ and time to find all the pieces necessary. If you use the th400 you can use a Gear Vendors OD which is awesome but you will spend about 3k on the unit and need to have your driveshaft shortened about 1 foot. If you want to keep your 456 gears you are going to have to do something with the th400. The gearing will be way to low for a 6bt. Swap your 456 for some 373 or 411s will help but minimally I still think you will need to beef up your th400 if you plan on using it at all in a towing/offroad situation.
Does anyone have an opinion on using a 700r4 auto. behind a 6bt as an alternative to using a Gear Vendors OD?

 

[Recovry4x4]

As much as a supporter as I am of the 700, it's not going to handle even a mild 5.9. I like the Muncie SM465 as a tranny and if I had the jack, I'd use that and a Ranger torque splitter.

 

[dan2002dd]

Thanks for the replies. I think I will try to start getting some parts together for the sway and see what kind of transmission I end up with and try to use one that came with the motor. I would like to know more about using an allison transmission. I think someone said you would need a divorced transfer case for this swap. Can someone explain this a little(maybe pictures). Would there be an issue on room to fit? Has anyone done this swap?

 

[mudguppy]

your current transfer is bolted onto the back of the transmission - this is called 'married'. with an allison transmission, there is not a transfer that is bolted onto the back, so a transfer is mounted independently and connected to the transmission via a short driveshaft - this arrangement is called 'divorced'.

short wheelbase vehicles usually have an issue running a divorced transfer because of the total length of the drivelive resulting in very short rear drive shaft, sometimes too short resulting in slip yoke splines pulled out or vibrations issues.

 

[Nonotagain]

your current transfer is bolted onto the back of the transmission - this is called 'married'. with an allison transmission, there is not a transfer that is bolted onto the back.

Except for the MD3070PT Allison transmission in which the transfer case is bolted to the rear end of the transmission with lots of bolts.

 

[Jones]

Good tip Nonotagain, but how plentiful are MD3070PT's? One thing that's always a consideration is availability of replacement parts.
Ask Jouquinsuave about having a transmission that even the manufacturer insisted they didn't make.

 

[Phily]

I have thought about doing a cummins swap myself on more than one occassion and have done some research. I know a few have done it here with success. the main question is what type of transmission do you want use to get the end result you want. Can you use the th400- yes - but you would most likely have to have it rebuilt/beefed up and add an OD to handle the added torque. If you go the route of a manual shift - which is the way to go - you will have to spend some $$$ and time to find all the pieces necessary. If you use the th400 you can use a Gear Vendors OD which is awesome but you will spend about 3k on the unit and need to have your driveshaft shortened about 1 foot. If you want to keep your 456 gears you are going to have to do something with the th400. The gearing will be way to low for a 6bt. Swap your 456 for some 373 or 411s will help but minimally I still think you will need to beef up your th400 if you plan on using it at all in a towing/offroad situation.
Does anyone have an opinion on using a 700r4 auto. behind a 6bt as an alternative to using a Gear Vendors OD?

Manuals are not the way to go. I've owned multiple Cummins. I can tell ya I'd rather have a ISB/TH400 in these trucks over a ISB/nv4500 or nv5600, etc. If you are crafty and got cash, put a beefed up 47re in. You'll roast tires in every gear, including lock up (and it'll last) . Stay away from manuals.

Being I currently don't own a CUCV. I'm not sure if I'd elect to re-gear or swap a different transmission. I would think a M1009 would be ideal being it's already geared to make 55mph driving possible. I'm not sure I'd be trying to a 6bt swap though, I'd shoot straight for the 4bt. The 4bt makes plenty of torque and isn't a 1200lb front end boat anchor. Not to mention, it'll net 30MPG on a bad day............Your offroading ability will suffer greatly w/ a 6bt, major ballast issues will result.

Is there a low stall available for the T400? That would help things out greatly too.

 

[1984CUCV]

Like I said it all depends on what you want to do with your truck. You can make just about anything work but will it fit your needs. Can you put in a 4bt? - yes- are the 4bt's easy to come by?- yes - Can you make decent HP with a 4bt? -yes - up to 250hp or so. However, the main reason I would not do a 4bt swap is the operating rpm range. 4bt are only rated to 130 hp give or take from the factory and well under 2000 rpms (usually 1600-1800 rpms). making a 4bt push upwards of 200+ hp the noise level would not be all that friendly to the people riding in a CUCV. Be my guest if you like wearing ear plugs all the time. Definately not the engine of choice for a daily driver.

The Gear Vedors OD is a really stout piece of work and can handle up to 1200 HP. Like I said it is not cheap but it will work great with a th400 or another auto for that matter if you want to use an auto.

 

[Croatan_Kid]

Yes there is a low stall for the 400s....it's what they have in them behind the 6.2.

The only problem with a 4bt is the cost. For what you'll pay for a decent, running 4bt, you could buy and slightly mod a 6 cyl. Plus, the 4cyls put out a lotttttt of vibration and noise. Great little motors though.


I'd like to hear more about your opinion on why a manual is not the way to go. Granted, I love the way a finely tuned automatic feels when it shifts behind a diesel motor, it's freakin great, but I couldn't live without the 5 speed in my truck. I'm just not a big fan of automatics in a big, heavy truck. I can't say that one is better than the other, it just seems easier to run a manual to me. It was also easier for me to find a matching transfer case.

 

[Alredneck]

I any of yall are looking for a good 5.9 and auto out of a running school bus hit woodywood up on here. He just got one off the auction and I think he put a add in the classifieds on here.

 

[Phily]

The only problem with a 4bt is the cost. For what you'll pay for a decent, running 4bt, you could buy and slightly mod a 6 cyl. Plus, the 4cyls put out a lotttttt of vibration and noise. Great little motors though.

100% agreed. The weight of the 5.9 is the problem. I'm going to be doing ballast tests this winter on the 4x4 Dodge Cummins just get a idea of where the numbers are.

4bt's can still make power; Diesel Power's: December 2009 issue has a guy claiming 800hp 4bt. I'm riding the fence on whether it's legit, but I mention it only for scale.

I'd like to hear more about your opinion on why a manual is not the way to go. Granted, I love the way a finely tuned automatic feels when it shifts behind a diesel motor, it's freakin great, but I couldn't live without the 5 speed in my truck. I'm just not a big fan of automatics in a big, heavy truck. I can't say that one is better than the other, it just seems easier to run a manual to me. It was also easier for me to find a matching transfer case.

My opinion is very slanted. So here goes......
The acceleration trumps a manual. I've owned both manual and automatic Cummins. Granted my automatic was heavily modified*, but it didn't take a few days and I knew I made a mistake doing a manual(after I bought my 2nd Cummins). You don't lose boost going through gears, after modding they hold up better, you can make most semi-autos. *My 98 ended up being a semi-auto, being able to manually control the gears and tcc lock up. Which is nice, I like to be able to decide when it shifts and have the option of letting it shift automaticly. I feel that's the best of both worlds. For the most part I did manually shift it however. PCM's are stupid.

Now for a super slanted opinion. I don't know my way around manuals. I can rebuild automatics and I live to mod automatics, Cummins/Torqueflites especially. Mods just seem endless. I bleed ATF. I blew up my 47re once and I nuked the clutch in my NV5600 and both cost about the same to fix, both took about the same time, both had about the same level of difficulty to fix. I have much more reasons, but I'm pretty sure nobody is reading by now.

 

[Detonation]

4bt's have been known to make over 600whp. There are definetly alot of 400+ whp 4bts out there without too much issue.

 

[Croatan_Kid]

Philly, those were exactly the reasons I was thinking of The automatic world has just exploded with mods once people figured out that diesels aint just loud, messy, slow and heavy! I too can build automatics all day, but I'm fixin to dive head first into my NV4500 to replace some synchros on 3rd gear and maybe 2nd. I helped a guy build an Allison in a Duramax once with a Suncoast Stage 3 kit and the parts alone were like 3,000 bucks! It was extremely beefy when we got done though.

I think my biggest reason for going manual was being able to run an NP205 transfer case and I didn't have to run cooler lines or anything like that, I wanted simple and enclosed lube systems with the least possibility of a leak. The sound is pretty awesome too! However, if I ever do another Cummins swap into a Chevy, it's gunna be automatic just so I have one of each

 

[mudguppy]

...4bt are only rated to 130 hp give or take from the factory and well under 2000 rpms (usually 1600-1800 rpms). making a 4bt push upwards of 200+ hp the noise level would not be all that friendly to the people riding in a CUCV. Be my guest if you like wearing ear plugs all the time. Definately not the engine of choice for a daily driver. ....

just like any other B-series cummins, it will run well over 3000 rpm and make well over twice the 'rated' hp and live for years. otherwise, you should tell the hundreds of folks using a '160hp 5.9' and making 500+ hp over 4k rpm that they can't do that.

there is significantly more vibration in the 4bt, though. but nothing that a good motor mount selection and fluid damper can't keep in check.

 

[dan2002dd]

Well I got a dodge truck tug with the cummins. What transmission comes in that truck?

1740 - Airfield Specialized Trucks & Trailers at Government Liquidation

 

[mudguppy]

Well I got a dodge truck tug with the cummins. What transmission comes in that truck?

1740 - Airfield Specialized Trucks & Trailers at Government Liquidation

likely an A727 TorqFlite - 3 speed auto, non-OD, non-lockup. fairly rugged, can be extremely rugged if you want it to be, but not the greatest choice behind a cummins because of the direct drive and no lockup on the converter.

 

[niferous]

Just to add my opinion which I'm not sure is worth much, I preferred my Dodge Diesels with a 5-speed Nv4500. I bought a 2001 with an automatic and let me tell you that thing was a dog. I couldn't pull anything well with it. I also had numerous tranmission problems that the dealership just couldn't fix right so they finally gave me a really smoking deal on financing, cost of a new truck, and more than blue book for my trade. I wound up getting a 2002 Dodge 4x4 with the 5-speed and after driving it I just can't imagine operating one with an automatic again.

Once again this is just my opinion with two trucks.

 

[Oasis-3]

I had a 1996 Dodge Cummins with the 5 speed and moved up to a 2001 Cummins with a 6 speed
It fixed the big jump from 3rd to 4th.
((( sorry for the hijack )))

 

[mudguppy]

a governor spring kit fixes the 3-4 jump for $100.

 

[mudguppy]

edit: double post.