QU10043AM 20 Tooth 10 Spline 1992-1994 GM NV4500 Input Shaft

QU10043AM 20 Tooth, 6.34 ratio, 1-1/8"-10 Spline 1992-1994 GM NV4500 Input Shaft (Main Drive Gear) for 1992-1994 GM New Venture NV4500 transmissions. A good quality reproduction gear for your early GM NV4500 transmission with the 6.34:1 1st gear and reverse gear ratios. Your matching gear on the countershaft must have 39 teeth. Made in Taiwan.

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Dan the Gear Man® Tech Notes:
Input Shaft Specs
Common Input Shaft Failures
Cryogenically Treated Gears
NV4500 Input Shaft
Matching Parts
NV4500 Synchronizer Parts
NV4500 Tools
Applications

Tech Note 1: Input Shaft Specs
QU10043 is a 20 tooth 1-1/8" x 10 spline replacement input shaft. The matching Countershaft Gear must have 39 teeth. The approximate overall length is 8-15/16". The stick-out length from the front of the transmission case is approximately 6-9/16". The tip for the pilot bearing is 0.59". Combined Input Shaft and Mainshaft End-Play should be set at 0.002"-0.006". QU10043 works with 1992-1994 GM transmissions with the 6.34:1 1st and reverse gear ratios.  It is NOT compatible with 1995-2007 GM NV4500 transmissions with the 5:61:1 first gear ratio.

Tech Note 2: Common Input Shaft Failures
The majority of NV4500 Input shaft failures are caused by one or more of the following:
#1. Failed clutch pilot bearing or bushing which chews up the input tip and can cause gear tooth breakage from misalignment between the engine and transmission.
#2. Running the transmission low on oil or with the wrong oil.
#3. Excessive horsepower which can cause either tooth breakage or the shaft to twist off.
#4. Bellhousing Index Hole off center and/or Bellhousing to block alignment pin(s) missing. A  gasoline engine bellhousing that has a bellhousing to transmission index hole that is more than 0.010" off center from the crankshaft centerline should be replaced.

Tech Note 3: Cryogenically Treated Gears
The GM New Venture NV4500 transmission was factory rated at 450 LB.-FT. of input torque. The infamous NV4500 fifth gear issue which plagues Dodge Diesel powered trucks is not a significant issue with any GM 4x2 model or 4x4 gasoline powered applications but it is something that does sometimes affect GM 4x4 diesel models. NV4500 performance and longevity is excellent with stock gasoline engines and good with diesel engines.

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 4: NV4500 Input Shaft
The New Venture NV4500 Input Shaft is designed to use three bearings. The input shaft is supported by a pressed-on Timken® high-performance Tapered Bearing Set. The back of the input shaft is bored for straight, caged roller bearing. The back face of the input shaft is ground flat for contacting the mainshaft to input thrust bearing. Another design feature of NV4500 input shafts is the 4th gear clutch ring is not an integral part of the input shaft, instead it is a slip fit to splines machined behind the input gear teeth. Incidentally, with the NV4500, 4th "gear" is simply a direct connection between the input shaft and output shaft with no power transfer through the countershaft.

Tech Note 5: Matching Parts
Matching Parts for QU10043 Input Shaft:
QU10049 or QU10702 4th Gear Clutch
QU10196 1992-1994 GM Input Bearing Retainer
QU10124 Timken® High Performance Input Bearing
QU10125 Timken® High Performance Input Bearing Cup
QU10133 NV4500 Input Pocket Bearing
QU10134 NV4500 Input Thrust Bearing
QU10126 Input Seal
QA10009 Mainshaft Shim Kit
QU10009B Basic Mainshaft Shim Kit
QK1010 Complete Small Parts Kit
QU10221 Basic Small Parts Kit
QU10093 39 Tooth Countershaft Drive Gear for 1992-1995 with Modular Countershaft
QU90020 NV4500 Manual Transmission Oil
TM1003 NV4500 Shop Manual
VSG1003DVD NV4500 Overhaul Video

Tech Note 6: NV4500 Synchronizer Parts
Matching NV4500 Synchronizer Parts for QU10043 Input Gear are: 

Tech Note 7: 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.

Applications
Chevy and GMC:
All Models with Original 6.34:1 Ist and Reverse Gear Ratio NV4500 Manual Transmission: 1992, 1993, 1994