Swap a G56 for a NV5600?

[dieselcruiserhead]

I'm doing a project and wanted a 6 speed trans, so I bought a complete NV5600. . I actually had it completely rebuilt with a two year warranty by the best trans builders in Utah so I am a pretty penny into it. I got it mocked up in the truck, so I have a fair amount of labor into it too... But at the end of the day, it is still 450 lbs and massive. . I just got a comment from a friend that it makes my Cummins 4BT look like a 22RE (famous little Toyota 4 cyl). . It also puts my rear driveshaft way back there on a 106" wheelbase. . But again I can make it work. .

Anyway, considering swapping the whole setup for the smaller, aluminum and lighter G56 combo if I can find someone who wants to swap. . I'll suffer from the same slightly lower top end as you guys as I'm limited to 4. 10 with the axles I'm running. I will have 35" tires so I'll be cruising around 2100 rpms at about 70 which is still a hair too high for my liking. . But I think the lower low might be nicer, and again the weight and overall size is nice for me...

Anyway, you guys think this is an easily doable swap for you guys, are people actually interested in this swap? I believe the G56 has a dual diaphram? I have the complete 5600 combo including the clutch and flywheel. . I was thinking keep the flywheel and use a 5600 straight clutch with the G56, if the input shafts are the same (??)...

another interesting thing I found out is the master/clave combo is the same from '03-'08, Dodge # 5211-0495AE, despite the different clutch setups. I took a measurement on one in a new Dodge last night. . When pushing the pedal I noticed some play of the master in the firewall in the brand new truck. . So I would recommend checking this out for any of you with brand new trucks...

 

[dieselcruiserhead]

Pics of the NV5600 behind the 4BT, you can see what I mean by making it look small...

 

[jwilliams3]

That dang NV is massive :-laf Hopefully some smart individual trades you out.

 

[dieselcruiserhead]

That is the question. . I have heard a lot of gripes from guys with the G56 that they don't like especially the top speed. . Which is an issue for me but I think the size/weight of the G56 outweighs the final drive ratio... Other than the top speed I think I actually prefer the G56 gearing...



What are the other gripes of the G56. . ? I have been reading a lot on them mostly here on TDR and as far as I can tell it is in my interest too...

 

[AKaiser]

Other than the top speed, the G56 is an excellent transmission.

 

[JFaulkner]

The only other gripe I've seen other than the OEM clutch is some have broken the aluminum case sledpulling. (but some people can break an anvil with a rubber mallet). So from what I've seen they're a good transmission but you can only abuse somthing so much.

 

[BSwope]

Man id really like to have that transmission!!!!!!!!! What all would i need to do to the drive shafts and cross member to make it work in my 06?

 

[JBeasley]

I replaced my NV4500 for a g56 in my 97 last summer. My 05 had the g56 and so does my 06. I pull a trailer alot and sled pull alot and have had zero problems with the g56. The lower gearing doesn't bother me because I'm running big tires. The biggest thing I like about it is it shifts alot easier than the 5600. I can keep up with my automatic driving friends now drag racing. I've heard the aluminum case is good up to about 700hp even doing alot of sled pulling. From what I've been told and experinced myself is that the internals of the g56 are stronger than the 5600. The solid mass flywheel and clutch from the 5600 will not work with the g56. The input shaft on the g56 is longer to allow for the thick dual mass flywheel. Southbend can hook you up with a clutch and solid mass flywheel to replace the DMF. I'm using southbend clutches with both of my g56's and love them. You will need to drill new holes in the crossmember and the rear driveshaft will have to be shortened and the front lengthed. The g56 is 3 inches shorter but it is deeper and wider than the 5600. Infact, if you put a g56 in a second gen truck you almost have to put a 2" body lift on to have room to even fit it under the floor pan because the floor hump is narrower and not as tall as the 03 and up. I've never weighed the g56 but it feels just as heavy as the 5600 and setting side by side the g56 actually looks bigger because its only 3" shorter but it's bigger around. Sorry for the long post. Hope this helps.

 

[mhenon]

Man id really like to have that transmission!!!!!!!!!

There have been a few complaints about the NV5600 (just a few) but I wouldn't trade mine for anything. Pretty darn good match for the mighty Cummins!

Mike

 

[AKaiser]

I replaced my NV4500 for a g56 in my 97 last summer... Southbend can hook you up with a clutch and solid mass flywheel to replace the DMF. I'm using southbend clutches with both of my g56's and love them.

Couple of ?s



1. How much more noise do you get with the SBC unit vice the stock LUK DMF unit?



2. SBC SMF Shifting response: Better, No Difference, Worse?



3. (Sorry, apparently counting to two not my strong suit) Does the SBC fix the intermittent long crank problem?

 

[BSwope]

Noise wise the new Sprung Hub DD's from SB are really quiet!!

 

[dieselcruiserhead]

This is all good info, thanks guys. .