Is this a Dodge NV4500 or GM NV4500? They are slightly different. The dodge one is a little more beefier than the GM in the input shaft do to it being slightly larger. The splines are different in the output of the main shaft. Dodge NV4500 has issues with 5th sliding off the counter shaft while towing. There is a fix for that. GM doesn't have that problem since it has a retaining nut and sleeve holding it in place. I don't know if you can mod a GM to Dodge or vice versa but dodge also came out with NV5600 which was behind there Cummins. But before you install the NV4500, I would cryo treat the input shaft, counter shaft, 3rd gear, and main shaft which it will give it 30% more strength. Make sure you check the tranny over before install. For example, my GM NV4500 I just got back from A&A transmissions in Yukon, OK, it has now has been modified. In it's stock configuration I had an input torque of 475lb-ft. After having the main shaft replaced since I stripped the splines along with the Gearvendors coupler, I ordered it cryoed. When removing the tranny I found the bell housing bolts on the driver side from tranny stripped. The tranny mount had one ear broken off and the other side cracked. The input shaft where the piolet bushing touched was worn badly. So I ordered the input shaft as well. Then had the counter and third shipped to Midwest transmissions for cryo treatment. I'm now in the process of putting it in. My new input torque is 613lb-ft. If you like more information on upgrading your NV3500,4500, and 5600 PM me and I can route you to the right people. If you get the NV5600 Cryoed then your input torque will be 706lb-ft. Lastly, I like to add, I also had a bearing and 2nd gear synco go bad prematurely. This is due to not having the right oil in it and in the GM version fills a quart lower than the Dodge. If you have the GM version then fill it to the fill port then add a quart to the top. Castrol does not make the oil used in this particular transmission. GM and Dodge still has them. GM part #12346190 and Chrysler part #4874459. Amsoil has started making it as well and is little cheaper then GM and Chrysler, Theirs is Manual Transmission & Transaxle Gear Lube 75W-90.
GM NV4500 Transmission
The 1992-1994 GM NV4500 transmission had an extremely low first gear ratio of 6.34, a 3.44 2nd gear, a 1.71 3rd gear and a 4.685” front bolt pattern. In 1995, the GM NV4500 received the same 5.61 first gear ratio and 6.043” bolt pattern that was found in the Dodge NV4500, along with a 3.04 2nd gear and a 1.67 3rd gear. A fully synchronized reverse gear was also added, and the front bearing retainer grew from 5.125” to 5.6” in diameter. Noticeable differences on the GM NV4500 4WD transmission include a 1 1/8” x 6 5/8” 10 spline input shaft (0.590” pilot tip), and a 32 spline output shaft, with an 8 1/8” tail housing.
GM NV4500 Transmission Gear Ratios
1st = 6.34 | 5.61
2nd = 3.44 | 3.04
3rd = 1.71 | 1.67
4th = 1.00
5th = 0.73 | 0.75
R = 6.34 | 5.61 | 5.04 (after 1998)
Dodge NV4500 Transmission
Used in Dodge trucks from 1992 – 1997, the Dodge NV4500 had a higher gear ratio than the GM variant. It shared the same bellhousing bolt pattern as the 1995 – 2005 GM version. But all forward and reverse gears were fully synchronized with carbon fiber composite synchronizer rings, and dual cone synchronizers for first and second gear. The NV4500 1-2 synchronizer assembly also had an integrated interlock mechanism that would prevent accidental 2-1 down shifts at higher speeds. There was a concentric internal hydraulic slave cylinder with an integrated throw-out bearing. And 1992 versions got a 19 spline, 1” diameter input shaft. 1993 and up models had a 1.25” diameter input shaft with 10 splines. 2WD versions got a 30 spline output shaft, 4WD got a 23 spline output shaft, but that was changed to a 29 spline shaft after 2001.
Dodge NV4500 Transmission Gear Ratios
1st = 5.61
2nd = 3.04
3rd = 1.67
4th = 1.00
5th = 0.75
R = 5.61 | 5.04 (after 1998)
NV4500 Transmission Gear Ratios
1st = 6.34 | 5.61
2nd = 3.44 | 3.04
3rd = 1.71 | 1.67
4th = 1.00
5th = 0.73 | 0.75
R = 6.34 | 5.61 | 5.04 (after 1998)
NV5600 Technical Specs
Case: Cast-iron with aluminum bellhousing
Torque capacity: 550 lb-ft
Weight: 360 lbs
Fluid capacity: 4.75 – 5 qts
Fluid type: Mopar manual transmission fluid PN 4874464
NV5600 Transmission Gear Ratios
1st = 5.63
2nd = 3.38
3rd = 2.04
4th = 1.39
5th = 1.00
6th = 0.73
R = 5.63
Common NV5600 Transmission Problems
Rear bearing failure
Cracked transmission case
Synchronizer failures