QU10729 NV4500 Countershaft 5th Gear


QU10729 6.46" Diameter 51 Tooth 1992-1994 GM NV4500 Countershaft 5th Gear is a quality replacement 51 Tooth Countershaft 5th Gear for all 1992-1994 GM NV4500 transmissions with 6.34 1st and reverse gear ratios. Your matching driven mainshaft 5th gear must have 19 teeth. Imported.

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:
QU10729 is a 51 tooth, 6.46" outside diameter, bearing supported gear that fits on the back of 1992-1994 GM NV4500 Countershafts. The transmissions that use this gear will have 6.34:1 1st gear and reverse gear ratios. The matching mainshaft 5th gear MUST have 19 teeth. QU10729 is NOT compatible with any other NV4500 transmission application.

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 GM NV4500 transmission is only 450 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 QU10729 Countershaft Gear:
QU10141 Countershaft 5th Gear Bearing
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
QU10728 Mainshaft 5th Gear 
QU10090 Modular Countershaft
QU90020 NV4500 Manual Transmission Oil
TM1003 NV4500 Shop Manual
V1003DVD NV4500 Overhaul Video




Chevy and GMC:
1992-1994 All with MT8 New Venture NV4500 5 Speed Manual Transmission