Max's 1st gen NV4500/4x4/dually conversion/upgrade

["Mad Max"]

Okie dokie, this subject has been covered by lots of folks, and there's lots of info out there, and what I've discovered is that each new thread, no matter how many, has new info in it, so, here's my thread on the subject .



This is the classic 2x4 auto-to-4x4 manual conversion, and I'll update the thread as I go along.



EDIT (Aug 07): I was doing a 5-speed conversion; have since decided to do a NV5600 6-speed.



Truck being converted: 1993 D250 Cummins, A-518 auto-o/d, 2-wheel drive



Conversions/upgrades being done:

- NV5600 6-speed

- 4wd (NP205)

- Dually (Dana 80 rear and Dana 60 front)



Finding parts is easy, knowing which ones will work between the generations is what's tricky. There are kits out there and they're awesome, and they priced accordingly. If you want it all in a box, the kits are the way to go. If you're like me, however, and you like to tinker and you think spending hours in the bone yards is therapeutic, this thread is for you... . well it's for me too, but at least this way y'all will have a chance to chime in and let the rest of us know your challenges to this conversion.



This info is as good as I have found, and the disclaimer is that until I actually do this conversion I will say that all of the following should work as written. I'll update this thread as I continue with the mods.



NV5600 conversion:



- 2nd gen engine to bellhousing adaptor, a. k. a. ‘flywheel housing', ‘spacer'

- Pedals (1st gen Dodge from 72-80 [may require mods] and 81-93 without mods)

- 1st gen manual steering column (not required but removes unnecessary linkage)

- Hydraulics - Clutch system

-- 1st gen master cylinder, slave cylinder, connecting hose

--- Unknown if 1st gen slave will work with 5600 same as Getrag

- Flywheel - 2nd gen Cummins 6-speed (don't know upgrades/variations yet)

-- Stock is 12. 25”

-- 13" is upgrade of choice

- Pilot bushing/bearing

- Clutch assembly - several options, typically based on hp/tq output

-- Southbend, Sachs, Centerforce, Zoom - expect $500-1000 for the good stuff

- Bellhousing: Bell is an integral part of the NV5600

-- Fork

-- Throwout bearing

-- Starter, 2nd gen

- Shifter with ball, w/ transmission

-- Short-throw upgrade

- Transmission - several sources. One is generally as good as any other, even new verses used.





NV4500 conversion:



-- Need spacer from any 2nd gen '94-'02 Cummins truck, auto or manual

--- Mopar part # 4874537 - same # for auto and manual, '94-‘02

---- Actual part is embossed with '3923045'

--- Mopar part # 4746636 - available from '94-'96

---- Not confirmed, but should be same as #4874537

- Flywheel - 2nd gen Cummins 5-speed (don't know upgrades/variations yet)

-- Stock is 12. 25”

-- 13" is upgrade of choice

- Pilot bushing/bearing

- Clutch assembly - several options, typically based on hp/tq output

-- Southbend, Sachs, Centerforce, Zoom

- Bellhousing: Stock 2nd gen

-- Fork

-- Throwout bearing

-- Pilot Bearing: D: 0. 7720", O. D: 1. 0020", Width: 0. 6840

-- Pilot Bushing: I. D: 0. 760”, O. D: 1. 390”, Width: 0. 990”

-- Starter

- Shifter with ball, w/ transmission

-- Short-throw upgrade

- Transmission - several sources: Quad 4x4, Standard transmission are popular

-- Recommend new, with upgrades (5th gear nut, HD input shaft)





4x4 conversion with mated NP205:



- NP205 Transfer Case. Two versions: 23-spline (auto/A-518), 29-spline (manual/Getrag). 29-spline will bolt directly to a NV5600 with minor mods to the shaft coupler (may require shortening coupler). 29-spline will also bolt up to NV4500 w/o mods. 23-spline 205 requires mods and minor machine work to bolt up (Quad 4x4 has great info on 23-spline upgrades)

- Ideally, get mated 29-spline from behind 1st gen Getrag - bolts directly to back of NV5600 - little to no voodoo.

-- Double-female coupler connects NV5600 male output directly to NP205 male input. (shortening of coupler may be required). Connects NV4500 directly, no voodoo.

-- NV4500: Remove fluid seal inside NV4500 tailhousing (orginally sealed off the 2nd gen 241 t-case) - is unnecessary with the NP205. Fluid will splash/leak out the back of the main 4500 main case, and will just pool in the area made by both the NV4500 aluminum tailhousing and the 205 front cast iron coupler adaptor. The 205 has a seal on the input shaft and keeps the two from swapping fluid.

-- NV4500: Aluminum tailhousing is a very good factory piece. Replacement with cast iron unit is only possibly necessary for hard core 4x4 applications.

-- Probably requires driveshaft mods

-- Shifter linkage mods. Could fabricate mounts.

- Could do a divorced system with a 2wd NV4500





Dually conversion, Axles:



- Need very strong axles. Dana 60 for front, and Dana 70 or 80 for rear recommended.

-- Matching dually front and rear axles recommended

--- Wheels will be non-similar if, for example, front is SRW and rear is DRW

- Bed tire clearance

-- Dually bed is ideal, but fender flares are hard to find

- Gears: Depending on driver preferance, 3. 54 - 4. 10 ratio. Personally I like the 3. 54's even with heavy towing (18k gross). For very big weight the 3. 73 or 4. 10 will be very good and make launching easier. With a 3. 54 1st gear will actually be useful around town, which is what I prefer - in other words, why have a 5-speed and only use 4?





Voodoo (unknown's):



- Speedometer functionality between the years?

- NP205 shifter mods?

-- Bracket fabrication required for p-side mounting (NV4500's had d-side t-case mounting)



- M2

 

[ESchoon]

It will be interesting to watch this build, cause your RC has been as well. I can't wait to see your crew cab/ext. cab become a "Mega Cab" 1st generation style.

 

["Mad Max"]

Thanks Eric If I can get the cab all welded up nice and clean I'll be real happy. When the RC is finished in a few months... and after a break... and after I get married in June ... then I'll start working on "Big Mack".



Really, really big and very lucky score today. Found a '97 3500 1-ton Cummins 4x4 rig in the bone yard... and yup... it has a 5-speed Oo. uhh, actually, that should read it 'had' a 5-speed :-laf. My buddy owns the yard and we're all pulling the rig apart next week, so I can catalog all the bolts, parts, etc etc - very cool to find all the parts in one truck.

Previous owner blew up the engine , and the truck is pretty hammered, but the driveline is good, so, I found all the parts, and the little stuff, for my conversion - all except the 205. Still gotta dig up a 29-spline 205 from a getrag... keeping my eyes peeled.



As well, found a local transmission shop (Precision Standard, in Colorado Springs) that knows all the 'voodoo' for building the NV4500's, so my plan is now to take this '97 5-speed and have it rebuild locally along with all the voodoo and upgrade modifications (5th gear nut, HD input shaft, etc), and this way I also score a local 'bubba' that knows the job for future upgrades, etc. He also does 205's :-laf



... progress...



- M2

 

[Mopar_Tim]

... ... . sounds exactly like the drivetrain i am putting in my 79 trailduster ... ...



mine also went from a 2wd a-518 to a 4x4 nv4500

 

["Mad Max"]

Well, here's the assembled mock-up for the driveline - just to see if it all actually bolts up - it does. It'll be at least winter before I pull the trigger on the actual conversion, but at least the parts are ready.



#ad




So, in the end, it'll be NV4500 + NP205 + GV overdrive + 4. 10's + 35" tire (285-70/R19. 5) = 1800 rpm @ 80 mph. Sweet.



- M2

 

[ESchoon]

Max--how does the GV work? Is it controlled by a seperate lever or switch?

 

["Mad Max"]

Max--how does the GV work? Is it controlled by a seperate lever or switch?

Well, overall the GV is completely manually controlled, meaning the driver must either activate or deactivate it every time, upshifting or downshifting. When I ordered it I also ordered two 'switches' to activate it, not knowing how I'd ultimately do it.



In my case, I'll probably mostly use it for a double-overdrive, or 6th gear. I will be able to hit it in each gear, also known as 'splitting' gears. Under 20 mph there is an electric override cutoff, at which point if decelerating/downshifting, and you reach 20 mph, it will automatically disengage, making a distinct clunk as the planetaries unlock.



So, the typical scenario is, ... clutch in... shift into 3rd... clutch out, power, (top of 3rd) clutch in... GV on... clutch out, power, clutch in... GV off... shift into 4th... clutch out, power, (top of 4th) clutch in... GV on... clutch out, power

... . etc thru 5th-over... . cruise at 85 mph @ 1900 rpm - sweet.



- M2

 

[TKentch]

Need very strong axles[/U]. Dana 60 for front, and Dana 70 or 80 for rear recommended.

-- Matching dually front and rear axles recommended

--- Wheels will be non-similar if, for example, front is SRW and rear is DRW

- Bed tire clearance

-- Dually bed is ideal, but fender flares are hard to find

max, where are you located

i have a mint '93 dully box for sale if your interested

i changed over short-box

-- email address removed --

thanks,

tyler

 

["Mad Max"]

max, where are you located

i have a mint '93 dully box for sale if your interested

i changed over short-box

-- email address removed --

thanks,

tyler

Thanks Tyler - I appreciate the offer, but I have a real nice bed for the conversion. I've bene running it sans flares on my SRW chassis for a long time, just waiting for the conversion.



I am planning to fabricate a set of aluminum flares for the rig to exactly match the factory ones. It'll be a fun TIG project...



- M2



UPDATE: Not running the Gear Vendor. Decided to run a 3. 54 gear and the NV4500 'straight up'. My cruising rpm will be 1900 rpm @ 75 mph and 2050 rpm @ 80 mph. Just called Randy's Ring and Pinion, and they have everything for my D60 and D80 dually axles. Both axles came factory with 4. 10's, so I need to change the carrier assy in the 80 to accept the 3. 54's, but since I'm installing a fresh LSD it will also double as the correct carrier, and I can run 3. 54's without any voodoo. Sweet.



- M2

 

[THenningsen]

what is your plan for mounting the front axle? Is there a kit available? I am considering my own 4x2 to 4x4 conversion on a 2nd generation.

 

["Mad Max"]

For the front end I have actually a couple thoughts. First off I think I will be doing air bags on the rig, similarly to how I did the Ramcharger only with shorter arms and fatter bags for more weight control. The difference is the system for the diesel will be designed for ride control and heavy weight, while the RC was built for articulation. I'll be more or less duplicating the 2nd gen 4-link system with air bags verses coils, but the rear will be extremely heavy duty, completely built for carrying big loads, lots of tongue weight, and for ride quality. Essentially the rear will be a single trailing arm set up, probably built from 2. 5" square tube, going under the axle, with the air bags behind the axle verses above it.



Doing a bunch of engine upgrades in three weeks: Lots of fuel and pump upgrades, including a PDR fuel pin, 3400 rpm spring, full fuel adjustments, bump the timing, plus a PDR HX-35 turbo with 16cm collar, one of our own ASA cold-air Intakes (or course ), plus a full 4" exhaust including a prototype 4" downpipe I'll be TIG welding together maybe this weekend. I'm bolting everything up all at one time, and in the process I'm hoping to go from 128 hp tested on a dyno two weeks ago (stock settings), to around 280 hp tested after the mods on the same dyno. As well, adding 6 gauges: Tach, oil pressure, water temp, pyro, boost, and transmission temp. I have pics of the gauge pods on my 'readers rigs'. Plus I want to put in my 40/20/40 seat and my 'shelf' that bolts in where the sun visors go. Lots of little stuff.



Lots of little stuff to add up to one huge improvement in both performance, towing, and luxury.



- M2

 

[MRector]

Thanks for posting this, it is some very useful info!! Helped me out alot.



Mikey

 

["Mad Max"]

Small update on the rig. Still in the 'parts aquisition' mode, and I've decided to go with a 6-speed vs the 5-speed. So I've got a NV4500 (4x4) for sale, and I'm looking for a good used NV5600 from a 4x4.



EDIT: 5-speed is sold, 6-speed is bought.



Engine mods are done - power is up around 308 hp and 620 tq - plenty for what I need.



- M2

 

["Mad Max"]

Been looking for a while now, and finally scored on a rebuild/warrantied 6-speed locally from a good shop. FWIW, cost was $2000 plus a $500 core, and friends and neighbors that ain't bad.



Shot some comparison pics between the 4500 and 5600. Of note, the 5600 has an integral bellhousing while the 4500 does not. Oh, as a safety warning, the 6-speed is stupid heavy.



#ad




- with the 205 bolted up

#ad




- close up of the mating surfaces.

#ad




- M2

 

[JStokes]

Are you goig to sell the NV4500?

I amy be interested.

 

[JStokes]

Are you goig to sell the NV4500?

I may be interested.

 

["Mad Max"]

Cool - nothing wrong with it that I know of. Came from a running '97 and was pulled after the PO ran the engine dry and spun a rod bearing. All the clutch/bell housing/started stuff goes with it, but I need to keep the flywheel housing/adaptor.

- M2

 

[RyanB]

What year is the 6-speed? 1 1/4" imput or 1 3/8". Wishing now after doing my conversion that I would have just went with the 5-speed instead of the 6-speed.



RyanB

 

[Shadrach]

Hey MadMax What have you figured out about the clutch cylinders. I have a complete 97 truck to get my engine and trans from. I also have access to a 93 with a getrag than I can look at. It's a 4x4 but the rest is the same. I am trying to find out as much as possible before I spend lots of time trying to fit something in that won't go. I will be runing a SB Con OFE clutch kit. Shadrach

 

["Mad Max"]

What year is the 6-speed? 1 1/4" imput or 1 3/8". Wishing now after doing my conversion that I would have just went with the 5-speed instead of the 6-speed.



RyanB

It's a 1-3/8" from an '03. Me and Shadrach are working out how to mate a 1st gen master cylinder (w/ remoter reservoir) to a 3rd gen slave cylinder. I have a great custom hose shop in town that can make me any kind of hose I can imagine, so I'm pretty sure we can get the two clutch components to play nice together, just so long as I can bleed the system.

Then I need a flywheel and clutch from an '03 and a 6-speed shifter I'll have most of the parts for the swap. May stuff the 6-speed in the rig before doing the big conversion.

I'm still 99. 99% set on running 3. 54's but I may go with 3. 73's - jury's still out. My 12v likes the 1800-2000 rpm range more than 2100-2300 and the 3. 54's will give me a nice 1950 rpm at 80 mph with my 35" tires - sweeeeet. 3. 73's are a 100 rpm more. With 3. 54's I'll actually enjoy the super deep 1st and 2nd gear in the 5600.



Here's the gear-speed calculator I use. This is calibrated for 3. 54's, with a 35" tire, and a NV5600 6-speed. Note the sweet shift points. I also have the calculated speeds with a GV overdrive.



#ad




- M2