QU10203 51 Tooth 6.22" Diameter NV4500 Countershaft 5th Gear


QU10203 6.22" Diameter 51 Tooth NV4500 Countershaft 5th Gear Is a quality replacement 51 Tooth Countershaft 5th Gear for all Dodge and 1995-2007 NV4500 transmissions. QU10203 is compatable with all 5.61"1 1st gear ratio NV4500 transmissions including 1992-1993 Dodge NV4500, 1994-2005 Dodge NV4500LD, 1994-2004 Dodge NV4500HD models plus all 1995-2007 GM NV4500 Transmissions. Your matching driven mainshaft 5th gear must have 22 teeth. Imported.

Aftermarket NV4500 Countershaft 5th Gear
* Kits made up of multiple items may not show an inventory in-stock status but are almost always in stock!

tech note

Dan the Gear Man® Tech Note 1:
QU10203 is a 51 tooth, 6.22" outside diameter bearing supported gear that fits on the back of NV4500 Countershafts. The transmissions that use this gear will have 5.61:1 1st gear ratio and either 5.61 (1992-1996) or 5.04:1 (1997-2007) reverse gear ratios. The matching mainshaft 5th gear MUST have 22 teeth. QU10154 Gear replaces OE QU10029 5th Gear. QU10203 is NOT compatible with 1992-1994 GM NV4500 transmissions with 6.34:1 low gear ratio.

tech note

Dan the Gear Man® Tech Note 2:
Typically, Countershaft 5th gear tooth failures occur from one of three causes: low or improper oil, misalignment of the maishaft to countershaft, and excessive horsepower/torque (over 275hp/600 Lb-Ft of torque). Broken 5th gear teeth are almost always caused by a combination of shaft misalginment (loose bearings or defective tailhousing) and exceeding the demonstrated 600 Lb.Ft input strength limit of the NV4500.

There are claims that cryogenically treating NV4500 gears will increase gear strength as much as 30%. Unfortunately, there does not seem to be any peer-reviewed documentary evidence to support those claims. Cryogenically treating gears is primarily a cold-hardening process that changes the molecular structure of steel to decrease wear while retaining or increasing hardness. If properly done, it is probable the cryogenic treatment process does slightly increase the impact and fatigue resistance of NV4500 gears, but not enough to significantly increase the ability of an NV4500 transmission to reliably handle more than 600 Lb.-Ft. of input torque especially considering the maximum factory torque rating of the NV4500HD transmission is only 460 Lb.-Ft..

tech note

Dan the Gear Man® Tech Note 3:
Need Torque Specs or Rebuild procedures? Order my 116 page, full color illustrated NV4500 Rebuild Manual.

You will need some special tools to correctly service your NV4500 Transmission. The chart below lists our current NV4500 Special Tools for popular models.


Component 23 Spline
Dodge 4x4
29 Spline
Dodge 4x4
30 Spline
Dodge 4x2
31 Spline
Dodge 4x2
32 Spline
GM 4x4
35 Spline
GM 4x2
Mainshaft Nut QT2002 QT2001
QT2002 QT2001
1-1/2" Hex
Mainshaft Holding NLA QT2000 NLA QT2011 N/A N/A
5th Gear Nut
Torx® Cross Bolt
N/A QT9205 N/A QT9205 N/A N/A
Output Seal Installer N/A QT1801 N/A QT2058
Not Used Not Used
Tailshaft Bushing Remover and Installer Not Used Not Used Not Used QT2044 Not Used Not Used


Front Bearing Cup Installer
QT1802 Use with QT1101 or QT1119 Driver Handle. Also can use flat side to install Dodge 4x4 Rear Output Seal
Countershaft Front Bearing Installer QT2004 Can also use to press 3-4 Synchro Hub on original equipment mainshafts
Input Bearing & Countershaft Rear Bearing Installer QT2005 Can also use to install Input Seal
Input Bearing Cup Installer QT1801 Use with QT1100, QT1101, QT1116, or QT1119 Driver Handle.
Countershaft Support QT2006 Use to support front of countersahft when installing countershaft rear bearing
1-2 Synchronizer Support QT2008 Use to support 1-2 synchronizer hub during synchronizer assembly
10mm 1/2" Drive 12 Point Socket QT1020 USA Made Impact Socket for Factory Tailshaft Housing Bolts
Long Shank Punch for Shift Lug QT9300 3/16" x 8" Shank for 5th Gear Shift Lug Roll Pin
tech note

Dan the Gear Man® Tech Note 4:
Matching Parts for QU10203 Countershaft 5th Gear:
QU10140 Sealing Cap, Main Case Countershaft Front Bearing Bore
QK1102 Lock Ring Kit
QK1110 Thrust Washer Locating Pin Set
QK1099 Synchro Strut Set
QU10304 Countershaft 5th Gear Thrustwasher
QU10039 5th Gear Sliding Clutch Ring
QU10003 5th Gear Synchro Ring
QU10202 5th Gear Clutch
QU10007 or QU10086 Mainshaft 5th Gear Dodge NV4500LD and 1995-2007 GM
QU10067 Mainshaft 5th Gear 1994-2004 Dodge NV4500HD
QU10090 Modular Countershaft
QU10078 Countershaft Assembly for 1992-1996 EXCEPT GM with 6.34 Ratio
QU10192/QU10707 1997-2007 Countershaft Assemblies
QU90020 NV4500 Manual Transmission Oil
TM1003 NV4500 Shop Manual
V1003DVD NV4500 Overhaul Video


tech note

Dan the Gear Man® Tech Note 5:
Lubricants, Sealants, Threadlockers:
Early production NV4500 Transmissions used an anaerobic sealant (QU90003) to seal between the main case and input bearing retainer, top cover, and rear housing. Mid-production units used anaerobic sealant just on the input retainer and RTV for everything else. Later production transmissions used black RTV Sealant (QU90006 or QU90005) for everything. Either type of sealant works fine (except the PTO covers ALWAYS should be sealed with RTV), but I prefer RTV for all components. Regardless of which sealant you use, make sure excess sealant does not block the lube access hole at the top of input retainer pilot that fits into the transmission case. Also, the threaded holes in the main case for the four retainer bolts and 12 PTO bolts are open ended, so you must use new bolts with factory applied threadlocker or apply Threadlocker (S24200) to your existing bolts to prevent oil seepage past the bolt threads. See my TM1003 NV4500 Shop Manual or V1003DVD NV4500 Overhaul Video for more information.

Lubricant and Chemical List for NV4500 Transmissions
QU90020 NV4500 Manual Transmission Oil
QU90003 Anaerobic Sealant
QU90006 3.35 oz Ultra Black RTV Sealant
QU90005 0.5 oz Ultra Black RTV Sealant
S24200 6ml Medium Strength Blue Threadlocker
S9978 1 gram Medium Strength Blue Threadlocker
S9979 1 gram High Strength Red Threadlocker
S24026 High Temperature Threadlocker for Mainshaft Nut


Chevy and GMC:
1995-2007 All with New Venture MT8 or MW3 NV4500 5 Speed Manual Transmission

Dodge and Ram:
1992-1993 D and W Series with Gas Engines and New Venture NV4500 5 Speed Manual Transmission
1994-2005 Ram 2500, Ram 3500 with Gas V8 Engine and NV4500LD 5 Speed Manual Transmission
1994-2003 Ram 2500, Ram 3500 with V10 Engine and NV4500HD 5 Speed Manual Transmission
1994-2004 Ram 2500, Ram 3500 with Cummins Diesel and NV4500HD 5 Speed Manual Transmission