QU10090 Modular Design NV4500 Countershaft for early Dodge and GM

QU10090 Modular Design NV4500 Countershaft Only is a quality replacement part for all those early production GM and Dodge transmissions with changeable Countershaft gears for 6.34-1 and 5.61-1 ratios. These were used on all 1992-1994 transmissions and some 1995 units. You may even find one in an early 1996 NV4500 transmission. Imported.

Need More Info? Use the handy Links below to access over 40 years of Dan's product and vehicle specific Tech Notes to easily get the information you need for your vehicle's repair, maintenance, or upgrade project!

Dan the Gear Man® Tech Notes:
Gears
Input Shafts
Ratios
Product Note
Common Failures
NV4500 Tools
Matching Parts
Applications

Tech Note 1: Gears
All 1992-1995 GM NV4500 transmissions use the same main transmission case, however, the gearing will depend upon the year. From 1992-1994 GM NV4500 transmissions were built with 6.34:1 reverse and first gear ratios. These transmissions will have a 20 tooth input gear and a 39 tooth gear on the front of the countershaft. 1995 GM transmissions have 5.61:1 reverse and first gear ratios. 1995 transmissions have a 22 tooth input gear and a 38 tooth gear on the front of the countershaft. The table below shows the different gear tooth counts for the 1992-1995 era GM New Venture NV4500 5 speed manual transmissions. The 1st, 2nd, and Reverse gears are the same for both 1992-1994 and 1995 versions, but most 1995 transmissions will have QU10078 1 piece countershaft instead of QU10090 modular countershaft with replaceable gears used on 1992-1994 and early 1995 transmissions.

Tech Note 2: Input Shafts
Five different input shafts were used to drive QU10090 Countershaft depending upon the year and make. Applications are listed through 1996 although it would be unusual to find QU10090 factory installed in a 1996 transmission.

Tech Note 3: Ratios
The NV4500 transmission was initially designed to allow for close, medium, and wide ratio models, plus there were plans for a NV4600 6 speed with a double overdrive. Only the wide and medium ratio 5 speed versions saw production. GM used the wide ratio version with 6.34:1 1st and reverse gear ratios in 1992 to 1994 trucks. Dodge used the medium ratio version with 5.61:1 1st and reverse gears from 1992-1996 as did GM for 1995-1996. QU10090 Countershaft is made so the two front gears can be changed to provide different gear ratios. The shaft is keyed slotted for thick drive keys (QK1129) for each gear, plus the gears themselves are designed to be a very tight interference (press) fit to the countershaft.

Tech Note 4: Product Note
The original NVG countershaft was grooved at the back end for a 0.050" snap ring. Our current production QU10090 Countershaft is grooved at the back end to accept a 0.100" thick snap ring to retain the 5th gear clutch just like later QU10078 Countershaft Assemblies. Both 0.050" and 0.100" snap ring sizes are included in QK1102 Lock Ring Kit. Combined Countershaft End-Play should be set at 0.002"-0.006".

Tech Note 5: Common Failures
Typically, Countershaft gear tooth failures occur from one of three causes: low or improper oil, clutch pilot bearing failures (which cause misalignment of the input shaft), and excessive horsepower/torque (over 275hp/600 lb-ft of torque). Broken 3rd gear teeth are almost always caused by 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 6: NV4500 Tools
Need Torque Specs or Rebuild procedures? Order my 116 page, full color illustrated TM1003 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.

Tech Note 7: Matching Parts
Matching Parts for  QU10090 Countershaft:
QU10078 One Piece Countershaft Assembly for 5.61 Ratio
QU10140 Sealing Cap, Main Case Countershaft Front Bearing Bore
QK1129 Drive Key Kit
QK1102 Lock Ring Kit
QK1110 Thrust Washer Locating Pin Set
QU10141 Countershaft 5th Gear Bearing
QU10142 Timken High Performance Countershaft Front Bearing
QU10143 Timken High Performance Countershaft Front Bearing Cup
QU10144 Timken High Performance Countershaft Rear Bearing
QU10145 Timken High Performance Countershaft Rear Bearing Cup
QU10008 Countershaft Shim Kit
QU10008B Basic Countershaft Shim Kit
QK1010 Complete Small Parts Kit
QU10221 Basic Small Parts Kit
QU10202 5th Gear Clutch
QU10304 Countershaft 5th Gear Thrustwasher
QU10033 Reverse Idler Gear
QU90020 NV4500 Manual Transmission Oil
TM1003 NV4500 Shop Manual
V1003DVD NV4500 Overhaul Video
QT1802 Countershaft Front Bearing Cup Installer
QT2004 Countershaft Front Bearing Installer
QT2005 Counter Shaft Rear Bearing Installer
QT2006 Countershaft Support
For Gearing, see Tech Notes 1 and 2

Applications

Chevy and GMC:
New Venture NV4500 5 Speed Manual Transmission: 1992, 1993, 1994, early 1995

Dodge and Ram:
D and W Series with Gas Engines and New Venture NV4500 5 Speed Manual Transmission: 1992, 1993
Ram 2500, Ram 3500 with Manual Transmission: 1994, early 1995