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159 Posts
Discussion Starter · #1 ·
NV5600 Installed Into A 1998 12 Valve

By J. P. Callan

Installation infromation provide to the web by J. P. Callan who has installed the NV5600 in his 1998 12 Valve Ram.

Here's some info on the 6-speed transmission for the Dodge Rams. Some changes are on the wind. I'm planning
a swap-out of the NV4500HD in my 1998 2500 4x4 Quadcab for a 2000 1/2 NV5600 6-speed transmission. I don't
know if you driven a new Dodge with the 6-speed, but let me tell you, it's sweet.

The 1999 1/2 and 2000 0/2 NV5600 6-speed has a 1 1/4" input spline shaft. Starting in January or so, the revised
NV5600 gets a 1 3/8" input spline shaft and a heavier clutch with a 1 3/8" bore.

The new transmission is 5 1/2" longer, so the rear drive shaft must be shortened by 5 1/2" and the front drive
shaft lengthened by the same. While I could by 2000 vintage drive shafts as spare part, it's much cheaper to have a local
driveline shop make the changes and rebalance the existing drive shafts. A new 5 1/2" longer shift linkage rod from the
high/low/4WD range shift lever to the NV241HD transfer case is needed as is a different rear transmission mounting
bracket. Otherwise, that's it for parts.

The 6-speed is installed in my 1998 12-valve 2500 Quad-cab 4x4 and fits like a glove! I used a 2001 NV-5600
instead of a 1999 or 2000 version.

Chrylser and New Venture Gear beefed up the NV-5600 and the clutch for 2001 to better support up-rating the
engine. Research at the Chrylser Proving Ground and using test trucks with uprated engines revealed that the
transmission's input spline shaft sheared off (metal fatigue) after about 150,000 miles of towing their 20,000 lb.test trailer
all around the western USA. So for 2001, the NV-5600 has a 1 3/8" input spline shaft instead the 1 1/4" shaft used in
prior years. I had to replace my fly-wheel and clutch to accommodate the larger spline shaft. The new fly-wheel has an
improved, larger pilot bearing, too. The clutch is 330 mm in diameter instead of the 300 mm version found in the 2000
and prior years. The new clutch can handle much more torque and is quite a bit bigger, using double the number of bolts
to hold it to the fly-wheel.

J. P. Callan Portland, Ore.

159 Posts
Discussion Starter · #2 ·
The NV5600, which weighs in at 465 lbs. is rated to handle nearly 20% more torque then the NV4500HD five speed. First gear and high gear are essentially the same ratios for both the NV4500 & 5600. Reverse gear is lower in the 5600 then most 4500's. The direct gear (1:1 ratio) for the 5600 is 5th, in the 4500 it's 4th. From a drivability standpoint, the difference between the two transmissions is the close ratio spacing of the 5600 doing in five gears what the 4500 does in four. Close shift ratios is a great asset for hauling and towing but a bit of a liability for daily city driving. The 6th or overdrive gear is mounted on the front of the mainshaft instead of the back like the NV4500. Consequently, the NV5600 does not have the problem of the mainshaft nut backing off.

Upgrading Your Dodge To The NV5600 6 Speed

Installing a NV5600 6 speed in place of a NV4500HD in 1994 and newer trucks is a straight forward job. The conversion usually requires buying a new clutch with a 1.375" hub to match the input shaft of current production NV5600s, but it is possible (although not recommended) to get an early production transmission with a 1.250" input shaft.

159 Posts
Discussion Starter · #3 ·
NV5600 6 Speed Specifications:

Case:......Cast Iron
Bellhousing:......Aluminum Alloy
Torque Rating:......550 lb.-ft.
Gross Vehicle Weight:......16,000 lbs.
Gross Combined Weight:......26,000 lbs.
Transmission Weight:......360 lbs.
First Gear Ratio:......5.63-1
Second Gear Ratio:......3.38-1
Third Gear Ratio:......2.04-1
Fourth Gear Ratio:......1.39-1
Fifth Gear Ratio:......1.00-1
Sixth Gear Ratio: .073-1......(Overdrive)
Reverse Gear Ratio:......5.63-1
Oil Capacity:......9.5 pints
Oil Capacity with optional filter:..10 pints
Recommended Lubricant:.....Texaco STF
Input Shaft:..10 Spline, either 1.25" or 1.375"

big big difference in size and weight


159 Posts
Discussion Starter · #4 · (Edited)
A wide cross-member must be used in all NV5600 conversion applications. The vehicles must be visually inspected for the 11" wide cross-member. If your vehicle is not equipped with the wide cross-member, please be certain your vehicle falls within the 1998 and later category.

The standard rear mounts currently in your vehicle is the proper mounts for this conversion. The mount is Dodge part number 52019641 and 5202051AA.

The reverse switch wiring must be lengthened approximatel 30 inches,

The shift linkage to the transfer case must be lengthened.

No speedometer modifications are necessary as the 1998 and later Dodge 4wd vehicles use a differential speedometer, and converting to NV5600 six-speed transmission will not affect the current speedometer readings.

The rear shaft must be shortened about 5 1/2", and the front shaft must be lengthened about 5 1/2".

NV5600 transmission you will need to purchase a new clutch assembly and 13" flywheel
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