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Something Different, Swapping 6 for 5, 2 for 1

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In a 3rd Gen Ram, ever thought of swapping an NV5600 for an NV4500? What about a top-of-the line dual disc clutch for a single disc unit?



KORE’s Hemi-powered Ram 2500 race truck uses blueprinted Blumenthal NV4500 five speeds and South Bend single disc clutches. After a bunch of successful races with this truck, we decided to take the next logical step and upgrade (that’s right, I said, “upgrade”) our CTD-powered Beast to the same transmission and clutch.



For years the Beast used a tried and true NV5600 and South Bend dual disc clutch. Bulletproof. Zero problems – ever – except when the transmission caught fire after I rolled the truck at the Parker 425 in 2005. It took four fire extinguishers to put it out. And that time when the Banks Sidewinder motor was in it, running propane, nitrous and a turbo too big to imagine…



Anyway, all hard core race, prerunning and towing duties were easily handled by the NV5600 and South Bend Dual Disc clutch. So why change?



Well, first of all, I hate the NV5600. It’s a heavy, cumbersome, Pigosaurus. When I bought the truck new in 2002 I thought, “She’ll shift better after she breaks in. ” But she never did. To no avail I tried every trick synthetic lubricant on the market. Shifts were always rough and forced – as if the synchros were worn out. This was compounded by the fact that with a six speed transmission, you have to shift more often because the ratios are closer. This is fine for towing - but we only tow a 10,000 lb. trailer with a race truck on it. Pretty light by CTD standards.



Prerunning a race course off road in a big, properly-equipped diesel can be really fun, but not when it feels like a tow rig. A bunch of shifting for only 10 to 20 mph speed differentials is annoying. Another annoying thing is stabbing the throttle and waiting for the drive train to spool up. When I want to kick the truck sideways, I want the truck to respond immediately.



This leads me to MOI – Moment Of Inertia – friend and foe, depending on what you want it to do. Lots of MOI is good when you’re sled pulling and you don’t want your launch to be affected much by this thing called, “gravity. ” Spin something heavy and it won’t slow down easily, spin something light and it will slow down quickly. Conversely the heavy object won’t speed up fast, but the light object will. This is your clutch and flywheel in action.



A heavy flywheel and clutch is great for towing. When the motor revs up, the clutch is released slowly then the truck accelerates slowly and without incident. The heavy flywheel spins, helping the motor turn circular momentum into forward motion.



But what about when you’re not towing? Like when you’re on off road, on a big, silty hill climb with a sharp turn in the middle of it? The hill is steep, you’re losing power and you need to down shift to make the turn – but if you down shift, you will lose your momentum and slow to a crawl before the shift is complete, then you’ll dig yourself a hole and never escape the hill. You can remain in the higher gear and hope that the heavy flywheel will keep the motor spinning without stalling – or, using your light weight Blumenthal wide-ratio five speed NV4500 you can leave it in gear, stab the throttle at the apex of the turn and power through with the tires spinning due to your trick, superlight South Bend flywheel and single disc clutch assembly.



This is simply a different way of doing things. It's great for off road because the drivetrain becomes much more responsive - and the NV4500 weighs a couple hundred pounds less than an NV5600. It's great for city driving because you don't have to shift as often. This would also be an excellent retrofit option to replace an automatic transmission. Better mileage, better mileage, better mileage.



The entire procedure is pretty simple. Without the cross member fabrication our team can do this in under two hours - in the field.



I drank a cold coke and took photos while our Crew Chief installed these parts. I thought I would share this with the TDR.
 
Just for reference, this is South Bend Clutch's Dual Disc set up. It will hold massive horsepower and torque and seems to last forever. We've never been able to wear one out - even when pushing 700 hp.



This is not the set up we're installing. I want to show what the dual disc looks like and why it's heavier. There are simply more parts - another floating flywheel and friction disc. The extra weight is essential for towing and extreme competition like sled pulling.



We're going the opposite direction with this installation.
 
Next comes the friction disc. The pads are made from South Bend's proprietary ferrous/ceramic material that has a high coeficient of friction, yet withstands extreme heat without expanding and contracting much. This gives and even, smooth feel when the clutch is released.



I attached a close up of the clutch hub so you can see the latest engineering trick.



This clutch uses neoprene “springs” to absorb shock loads as they come back through the drive train, providing torque converter-like buffering in a stone-axe reliable package.



For us, this is the most important part of the clutch, since it protects the entire drive train from shock loads.
 
Did you get it together yet? How's it feel? Did it give the expected results? Did you do anything to address the 4500's weak points? (5th gear nut, small input shaft,... )

--Eric
 
Now the pressure plate.



Keep the clutch disc centered with an alignment tool (included with South Bend units) and snug her up.



Clutch is installed - no big deal.
 
Hello Kent,

Great to see you posting again. I always learn something every time you do... .



I think it is a great idea. Boardmaniac (God rest his soul) and i were discussing the option of switching trannies some time back. My 5600 has always been smooth but would like the option of less shifting and the wider ratios would likely mean faster acceleration.



Anyone near Spokane want to swap a 5 for a 6??????



My truck is in the shop for 2-3 weeks getting body work and repainted. More on the carnage in another post to come.



Best wishes to you and Sarah Mae.



DD
 
Next comes the transmission.



This is a complete Blumenthal NV 4500. The transmission looks so good, we put it in the studio for a glamour shot! ha ha!



Anyway, here's a little history behind it:



When New Venture changed hands, Blumenthal Mfg. bought all existing NV4500 prints, tooling and parts, making them the go-to source for these transmissions.



Monte Sellers is the man in charge of engineering at Blumenthal Mfg. For their production NV4500's, he pioneered the use of huge, 1 3/8 inch input shafts, strengthened the 5th gear assembly with a fully-splined main shaft and other parts (eliminating all 5th gear problems), replaced the factory composite synchro rings with bronze units and nearly doubled the fluid capacity with extruded aluminum coolers, making these transmissions bulletproof for sled pulling rigs creating an excess of 1000 ft. lbs. of torque.



Blumenthal is the official drive train remanufacturer for Mopar. They have a lot of experience with these transmissions. A technician at Blumenthal "blueprints" each of these transmissions during assembly, meaning they're assembled to the tight-side of the recommended tolerances, not just thrown together and sent out the door, meeting "spec. "



These transmissions are superb in our Hemi-powered race truck. And we do stuff with that thing that nobody in their right mind would ever do to their street truck.



In sum, this transmission is essentially a light weight, 5 speed NV5600. Stonger, faster, and lighter. Just what we wanted to upgrade the diesel truck that is destined for the Dakar (in Chile) next year.
 
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Hello Kent,

Great to see you posting again. I always learn something every time you do... .



I think it is a great idea. Boardmaniac (God rest his soul) and i were discussing the option of switching trannies some time back. My 5600 has always been smooth but would like the option of less shifting and the wider ratios would likely mean faster acceleration.



Anyone near Spokane want to swap a 5 for a 6??????



My truck is in the shop for 2-3 weeks getting body work and repainted. More on the carnage in another post to come.



Best wishes to you and Sarah Mae.



DD



Thanks, Dan,



We've been so busy around here getting new products to market I haven't had a spare moment to post. We're just now getting back to normal + I don't have any races until August.



Years ago, I remember driving Greg's truck and it shifted so smoothly. We also did a Death Valley trip together and drag raced Big Red against The Beast. We had similar horsepower and while I was shifting, he was accelerating. He basically beat me with his transmission - an NV4500. I'll never forget that.



Kent
 
Grease the input shaft. Be sure to use a rag or q-tips to push high-temperature grease in between the splines. You don't want a bunch of grease on the shaft, just a light coat, so the friction disc can "float" without binding.



Then throw her on a transmission jack and stab it - carefully.



The trick here is DON'T FORCE ANYTHING. Simply out think it. Look at the interface between the bell housing and the motor. Get everything as parallel as possible.



Put the transmission in gear (any gear) and turn the output shaft until you feel the input shaft's splines align with the clutch. It should slide right into place and stab the pilot bearing no problem.



Align the dowels with their respective holes and move the transmission forward gently. Do not use bolts to seat the bell housing. Get it flush against the motor with hand power only.



Now install the bolts through the bell housing, starting with the bolts that go throught the alignment dowels.
 
Nice write up,I have been flogging my 94 5spd truck for years. Tested many different cluthes and have ended up using the southbend line. I did break some teeth off 3rd gear,( too much torque)but the bearings and factory synchros were still like new,I attribute this to changing the fluid on a regular time table using the correct factory fill as well as running the fast coolers.

I heard you had trans issues during the last 500. Can you fill us in and maybe a few pointers on how to avoid such pitfalls?

Thanks,

Bob
 
Next are some adjustments.



Because the NV4500 is shorter than the 5600, everything gets moved forward. The front drive shaft needs to be shortened and the rear needs to be lengthened. Any driveline shop can do this with your existing parts.



A new cross member has to be built or the original one has to be relocated forward.



We opted to build our own, low-profile cross member.



Frank built this in about an hour from angle iron and rectangular tube. There are probably a hundred different ways to buld this part. Four tabs, two half inch bolts and two 7/16" bolts seemed to be the simplest way. Easy to repair in an austere environment as well.



This trans cross member is for a solid mount. For our race vehicles, we solid-mount the motor and transmission. For a street vehicle with stock motor mounts I would want a 1/2" thick piece of rubber sandwiched between the angle and the transmission. The OE transmission mount could also be adapted easily. It's a good part.



Before welding in place, be sure to check the angle of the motor/transmission assembly. You want to retain the OE cant. Our motor can't pivot in the mounts much, since they're solid, but a stock truck's motor mounts move significantly. You can reference the angle of the fan relative to the radiator for a good visual que, but an inclinometer put on the valve cover would probably be best.



Weld the tabs in place and you're finished with fabricating.



Frank's MIG welds are strong but hideous. Nobody around here comments because he benches about 400 lbs. and has killed many in Iraq...
 
We're still rebuilding The Beast after I rolled her last year. That's twice for this truck. I'm amazed that I'm still allowed to drive it!



It ended up being for the best because it was destined for Portugal two weeks after I tossed it away. Then they cancelled the race. Bad driving saved a bunch of hassle and expense in Europe.



I don't have a driving report on The Beast yet.



Currently we're getting the final details sorted out - spare parts location, pumps, shocks, electrical. Then the new cab goes on and we send her to DRC for race prep.



I'll post some current photos of the truck.



Meanwhile, this is an article about the Hemi - with the dual disc set up -destined for another magazine. We tested the dual disc, but raced with the single disc. We liked the spool up a lot better.



HIGH TECH OLD SCHOOL



The 2007 Baja 1000 was a disappointment for team KORE’s Dodge Stock Full race effort. While leading the class at mile 870, the truck’s 545RFE automatic transmission, standard equipment on Heavy Duty, Hemi-powered Rams, decided to commit suicide. After a transmission swap in the field, the truck was racing again, but that transmission soon failed as well, leading us to believe that the problem wasn’t with the transmission; it was with the brain – the TCU. The “FE” in the 545RFE means, “Fully Electronic,” so for this unit there is no building a manual valve body like you would in a good old Turbo 400. Electronic solenoids control everything. After the race we checked the transmission’s wiring harness, connectors, computers – everything. Nothing could be done to determine the root cause of the failures.

The punishment of desert racing is severe beyond belief. Intense vibrations, tremendous shock loads, water, dust, dirt, silt, sand and of course the worst of all environmental conditions – mung – all wreak havoc on delicate electronic operating systems that were never designed for that kind of punishment. Most fuel injection systems and transmission controllers run on sub 5 volt circuits, making them susceptible to interference from high-powered VHF race radios, fresh air pumpers, and electric cooling fans found on desert race vehicles. During the 2007 Vegas to Reno race, our finish was thwarted by limp modes and overheating due to the EFI thinking for itself. We found the situation untenable and decided to ditch the EFI in favor of a good old off-road-tuned Holley carburetor. Thankfully class rules allowed the swap. This decision that proved to be a good one, eliminating all induction-related failures completely.

The next problem to address was the drive train. Class rules prohibit changing to another brand of transmission. And without being able to modify the 545RFE to make it more robust, the KORE race program was coming to a standstill. Most V-8 powered race trucks use automatic transmissions - and for good reasons. Trucks are usually pretty heavy and have a forward weight bias, making a solid axle and a “locked” differential mandatory to prevent getting stuck in the loose stuff. Most V-8 powered race buggies use manual transaxles with “open” differentials. These cars have independent rear suspension and can’t have the wheels rotating at the same speed while the axles are in different vertical planes – drivers wouldn’t be able to keep them going in the intended direction. On a race buggy, because only one wheel is rotating at any given time, and because the axles absorb shock by working like torsion bars, they can get away with a clutch and manual gear box. They’re light and often have less than 500 hp, so they tend to hold up well. A full sized race truck, on the other hand, is much heavier, typically has more horsepower and generates two to three times the traction (if equipped with 4x4). Therefore, they put much more stress on the drive train. Blown gears, shattered ring and pinion sets and spiraled drive shafts are common. The hydraulic torque converter in an automatic transmission absorbs much of the shock loads that would otherwise be sent through the drive train. This is why manual transmissions are unheard of in off road race trucks.

What to do? It wouldn’t be smart to run the 545RFE again and risk spontaneous detonation. The only other transmission offered in this model of Ram was the venerable NV4500 – one of the toughest 5 speed manual transmissions ever made. The NV4500 is the universal heavy duty manual transmission; it’s been found in everything from jeeps to delivery trucks. It’s strong, quiet, shifts well, parts are available and at only 200 pounds, its’ even light weight, saving 50 to 100 lbs over automatic equivalents – much more if you add the coolers, lines and hoses required to make them live in the desert.

When New Venture changed hands, Blumenthal Mfg. bought all existing NV4500 prints, tooling and parts, making them the go-to source for these transmissions. Monte Sellers is the man in charge of engineering at Blumenthal Mfg. For their production NV4500’s, he pioneered the use of huge, 1 3/8 inch input shafts, strengthened the 5th gear main assembly, replaced the factory composite synchro rings with bronze units and nearly doubled the fluid capacity with special extruded aluminum coolers, making these transmissions bulletproof for sled pulling rigs creating an excess of 1000 ft. lbs. of torque. A Blumenthal NV4500 was the “turn key” manual box we were looking for.

So how do you make a manual transmission and drive train survive in a high performance off road race truck? You call Peter Pyfer at South Bend Clutch.

Peter is a master clutch designer and relishes the tough problems that people say can’t be solved. I presented the idea to Peter like this, “Can you make an SFI rated clutch that will hold 600 horsepower at 7500 rpm – and absorb shock loads like a high stall speed torque converter?” Peter had the solution before the phone call ended. His plan would entail using one of his existing dual disc designs, but with special “buffered” hubs. Dual disc clutches are tough to make because the tolerances must be so close. This would be the first dual disc clutch built for a 5. 7 Hemi motor, so everything had to be perfect. You have to fit a whole lot of stuff in a very small space: a flywheel, two friction discs, and a center plate – more than twice the amount of parts than what is found in a normal, single disc clutch. This leaves only . 040 of useable space for the clutch to open and close. The ferrous/ceramic material used by South Bend in their friction discs doesn’t expand or contract with heat and the billet flywheel and center plate are works CNC perfection. The best parts of the design are the trick clutch hubs that use neoprene “springs” to absorb shock loads as they come back through the drive train, providing torque converter-like buffering in stone-axe reliable package.

So how did it work, you may ask? We now many punishing races and thousands of test miles on this drive train. The Blumenthal NV4500 and South Bend Clutch have given us perfect performance. The great thing is that, without the hydraulic drag from the old auto, the manual transmission now gives us better acceleration and better fuel economy, the latter of which is very significant. We went from 2. 5 mpg to 4 mpg. just by switching to the manual transmission. 1. 5 mpg. may not seem like a lot – but that’s a 40% improvement! This is a pretty incredible side benefit when you think about how much simpler, lighter and more compact our drive train became by going high tech old school.
 
And here I thought back when I bought my 2003 truck in OCT 2002 with the SO motor and NV4500, that I was just doing to save money ($1000 was the up charge for the nv5600 and HO)...



Now it appears I have the better transmission! - I can tell you the reason other than the $1000 was because I HATED the notchiness of the NV5600 from the very first one I drove somewhere around 2001.





Kent, Is the NV4500 you have installed new and improved over the NV4500 dodge made in 2002-2003?
 
Tomeygun,



I'm not saying the 4500 is "better" than the 5600. The 5600 is a great transmission. I'm just saying that the NV4500 is better for our purposes. Far better.



I think if one regularly tows 15,000 + lbs, then the close ratio 5600 would be better. Splitting the 3rd gear ratio is nice for that.



Having driven both transmissions, for racing, off-road - and even around town driving I think the NV4500 is a much friendlier transmission.



We have four of them in the shop - all blueprinted Blumenthal models. Every part is new - including the cases. They contain the latest gears and modifications - 1 3/8" input shafts, 29 spline output, fully-splined main shaft etc. All those historical 5th gear problems have been totally engineered out by Blumenthal.



The one we currently have in our Hemi is actually a four speed. 5th gear at 7000 rpm is ridiculous, so we just left it out.



We use NEO MTL or the Blumenthal brand fluid. These trannies work great.



One thing we did learn recently was that when they start to feel loose - meaning more lash than normal - it's time to rebuild them. By "rebuild" I mean tighten them up again to get the gear teeth meshed deeply like when they're new. You don't have to replace parts, just shim, locktite and preload everything tight again.



During the Baja 500 we blew a tooth off of third gear. Post race inspection showed that all the gears still looked new, over time they had just developed some play, and the overlap wasn't enough for 3rd to survive. We could have thrown in the spare trans - so easy compared to an auto - four bolts to the bell housing - but we were behind due to steering issues early on.



We were essentially trying to see what kind of duty cycle we could get. Several thousand miles on a race transmission is a lot. Race miles are kind of like dog years. Each race mile is like 100 street miles. Now we know that, just like our ring and pinion gears, shocks, steering components etc. , we have to tighten up the transmission every 1000 miles.



I think on the street and light duty off road (washboard roads etc. ) one could get 150-200K out of one of these new NV4500's. Easy.



Our truck puts out about 100 more horsepower than most Class 1 cars. Their Mendeola and Fortin transmissions cost upwards of $30,000 - and they regularly blow up + they usually need a rebuild after every race. Those rebuilds are not cheap.



We have more horsepower and less wheel travel than those buggies. This combination is hard on drivetrains. We're happy with our NV4500's. Inexpensive, super strong. Good stuff.
 
Tomeygun,

I'm not saying the 4500 is "better" than the 5600. The 5600 is a great transmission. I'm just saying that the NV4500 is better for our purposes. Far better. I think if one regularly tows 15,000 + lbs, then the close ratio 5600 would be better. Splitting the 3rd gear ratio is nice for that.



I certainly understand that - I really like my 4500 for racing, but get 10k behind it (coupled with a 66mm turbo) and I find myself shifting at 3200 rpm everytime to stay above the turbo.



We use NEO MTL or the Blumenthal brand fluid. These trannies work great.



Have you noticed faster shifting with this fluid? My synchronizers seem to be a bit too slow sometimes to let me shift fast... I am about due for a fluid change anyway.



Also great info on the shim/rebuilt details
 
With the NEO I didn't notice faster shifting at first. The NV4500 shifts smoothly, but I wouldn't call it fast. The shift throw is too long and the internal parts are massive.



The big difference we saw - huge difference really - was the temperature drop with this fluid. We have a Nordskog temperature gauge and the sender is in one of the extruded aluminum coolers on the transmission.



Normally the transmission would operate a about 40-50 degrees above the water temperature. In sand washes it would sometimes go up to 280 - like during the San Felipe race. Now we can hardly get it above 220 - no matter what the conditions. Normal for the transmission is around 200 or less with the NEO. It's great to see three temperature gauges - water, motor oil, and trans - all within five degrees of each other.



Jason Hughes at HRC in San Diego introduced us to NEO. Evidently this fluid is for NASCAR and is run in over the road truck transmissions as well. He knows a lot more about it than I do.
 
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