Engine/Transmission (1994 - 1998) NV4500 to NV5600 swap, with newer axles.

[CRWilliams]

Hey guys. I finally got around to doing my transmission and axle swap. I swapped my NV4500 for an NV5600 out of an '01 along with a DHD transfer case. Thought I would share a couple of things I found. This was a PIECE OF CAKE on my '98. I was expecting to lengthen the reverse light wiring, but apparently Dodge was already planning the NV5600 prior to the '98 model year as the reverse light wiring had lots of extra wire folded and taped up.



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I did have to lengthen the vacuum and vent lines to the transfer case, but that was easy enough. I have yet to lengthen the transfer case shift rod, but that's also no big deal. I knew the NV5600 was about 6" longer than the NV4500 and was going to have a drive shaft built prior to starting the swap, but decided against it as I wanted to measure to be triple sure that the length was right. Turned out it was a good thing I did as the NP241DHD transfer case is about 3/4" longer than the DLD, so the shaft needed shortened 6 3/4". I already had the slip yoke for the DHD so that was no problem. I already had a front drive shaft from an NV5600 truck rebuilt and ready. I had the starter spacer and NV5600 double disc clutch, that were installed as well. The crossmember fit fine as the '98 already had the big crossmember.



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I also swapped out the drum brake rear today for the disc brake rear. The rear brakes will need some attention soon, but I replaced all the brake lines and parking brake cables as they were all damaged on the rear. I also replaced the rear shocks as the Tuff Country shocks were both blown. Will never buy those again. Less than two years old and no gas and one seal leaking. There is also at least one of the front shocks that is blown and leaking fluid. Thought I would try the KYB Monomax shocks. Found a great deal on them at Summit Racing, along with a new steering stabilizer. Didn't think I should leave the Tuff Country one on while replacing all the blown shocks.



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The front axle is on the agenda for tomorrow, and maybe the 4-wheel disc master cylinder if time allows. Getting pretty excited to drive it now that's it's so close to being done.

 

[CTD12V]

So, how are you liking it, now that it's been several months? What did you do to the front axle?



CTD12V

 

[CRWilliams]

Actually, I guess I posted lots more on a couple of the other forums since I got a lot more interest there. Not sure if they'll let me, but I'll try posting the links to those forums. Let's give this a try. NV4500 to NV5600 swap with newer axles - Dodge Diesel - Diesel Truck Resource Forums
NV4500 to NV5600 swap done - Dodge Cummins Diesel Forum

 

[Matt42]

CR: That is a nice looking job. I've always wanted a gear between third and fourth. At work, I drive a 04. 5 that has the NV 5600 with that "extra gear. " his is a conversion I make one day, along with a rear disc conversion.



The NV conversions seem to have been overshadowed by the Getrag conversions, and that is too bad. It's nice to be able to do this without so much surgery to the truck.

 

[CTD12V]

I think the reason the G56 conversions seem to be more popular is because parts for the NV5600 are getting hard to find since it has been discontinued. Also, from what I've read, the G56 seems to be a smoother-shifting transmission. I wish I could drive both back to back and compare them.

 

[Matt42]

G56 is smoother to shift than NV 5600

-snip- Also, from what I've read, the G56 seems to be a smoother-shifting transmission. I wish I could drive both back to back and compare them.

I have to agree with the observations that the G56 is smoother to shift than the NV 5600. Much smoother, in fact. I am assigned a 2004. 5 CTD with the NT 5600 at work. A colleague in another office in an adjacent state uses a 2007 CTD with the G56. We often work together on assignments. On a recent assignment, we had both trucks with us. The difference was astounding.



The NV 5600, at least in this particular truck, has always had a sort of a vague feel to it. (Though never as bad as a transmission in a Fiat 850 or a 128!) The gate into 3rd is frequently hard to find, and it's easy to miss, getting into 5th instead. 5th is also vague, getting into 3rd. Inexperienced drivers can get the grind of reverse. But with experience and careful shifting, the NV 5600 is a perfectly fine transmission. Speed shifts are out of the question. If the driver gives the synchronizer rings time to work, all is well.



On the other hand, the G56 has a very crisp feel, as if the shift pattern is working through well defined gates that were flame cut hardened steel guides. It took no time at all to get used to and was a pleasure to drive.



I can't compare how the trucks and transmissions did under load. The older truck with the smaller and less powerful engine was towing the heaviest load (naturally), so there was really no way to compare.



If I was to make the conversion on my own truck, with my lighter usage, I'd probably go with the NV 5600 because of what appears to be the easier bolt-up job. But that's not on my project list.

 

[CTD12V]

Hey Matt,



Thanks for the real-world feedback on that. Your experience is similar to other things I've heard, but I haven't ever had anyone tell me what it was like driving them back to back.

 

[Matt42]

You're welcome! The hardest part for me was the similarity in cab layouts and the different placement of reverse. At the end of a long day, or early in the morning with insufficient coffee on board, no matter which truck I got into, we would invariable go for the reverse in the wrong place.



Our project location was a 900 mile drive for me, 650 miles for my coworker. As we departed from his office, we headed out with him in the lead. I was driving the 2004. 5 with a GCVW of about 19,000 lbs. He was at about 12,000 lbs with his 2007. After several hours and several sets of mountain ranges on US 95, we decided to switch positions. I couldn't easily keep quite the same pace.



We had both CB and dedicated FM digital radio contact, so we were able to monitor some fascinating radio chatter.