QU10215 NV4500 1-2 Synchronizer Assembly with Shift Interlock


QU10215 1992-1994 GM NV4500 1-2 Synchronizer Assembly With Shift Interlock is a genuine New Venture Gear 1st-2nd Synchronizer Assembly for 1992-1994 GM NV4500 5 speed manual transmissions with 6.34:1 1st gear ratio. QU10215 is factory assembled and it includes QU10038A Hub, QU10081 Clutch Ring, QK1085 Interlock Parts Kit, and QK1100 Synchro Strut Kit. New Takeout part from brand new transmissions we disassembled for parts. NOTE: The shift Interlock feature was usually not used on transmissions with 5.61:1 1st gear ratio. 

Also see QK1058 1-2 Synchro without Shift Interlock

1-2 Synchronizer Assembly
* 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:
QK1058 and QU10215 1-2 Synchronizer Assemblies for New Venture NV4500 5 speed manual transmissions are physically interchangeable. The interlock feature, which was used on 1992-1994 GM transmissions with 6.34: 1st gear ratio, was designed to prevent high speed down shifting in 1st and 2nd gear. To accomplish this, four sliding blocks and two springs are added to the synchro hub. When the mainshaft is rotating at high speeds, centrifugal force pushes the blocks against the sliding clutch ring and locks it in place. The early synchro hubs were slotted for the four blocks, plus there was four holes in it for the spring hooks. Once the interlock feature was abandoned after 1994/1995, the synchro hub was redesigned to eliminate the hub slots and holes. If you have the early QU10215 Synchronizer with interlock, you can convert it to a non-interlock unit simply by removing the four flyweight blocks and two c-shaped springs. The sliding hub plus the synchro springs and rectangular struts are the same for all years and models.

tech note

Dan the Gear Man® Tech Note 2:
All New Venture NV4500 transmissions use three synchronizer rings for 1st gear and for 2nd gear. The inner and outer rings are made of steel, while the center ring is faced with carbon fiber on both sides. 

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 Popular Mainshaft Part Numbers for QU10215 1st-2nd Synchro are:

Application Mainshaft Engine Output Spline
1992-2007 GM 4x4 QU10098 All 32
1997-2007 GM C-Series 4x2 QU10719 All 35
tech note

Dan the Gear Man® Tech Note 5:
NV4500 Transmissions have 3 1st Gear Synchronizer Rings. Matching Synchronizer Parts are:

Gear  Synchronizer
QK1058 Not Available QU10081 QK1100 QU10002**
QU10215* Not Available QU10081 QK1100 QU10002**
1994-1995 Dodge QK1058 QU10038 QU10081 QK1100 QU10002**
1996-2007 All QK1058 QU10038 QU10081 QK1100 QU10002**

 *QU10215 1-2 Synchronizer Assembly with Shift Interlock can be replaced by QK1058 if desired. The Shift Interlock was intended to prevent down-shifting at high speeds.

**QU10002 is the Center Friction Ring. QU10014 is the Inner Steel Ring. QU10015 is the Outer Steel Ring.

tech note

Dan the Gear Man® Tech Note 6:
Other Matching Parts for QU10215 1st-2nd Synchro:
QU10002 Synchronizer Ring, Center Friction
QU10014 Synchronizer Ring, Inner Steel
QU10015 Synchronizer Ring, Outer Steel
QK1103 Snap Ring Kit, 1-2 Synchro
QU10075 39 Tooth Mainshaft 1st Gear
QU10035 37 Tooth Mainshaft 2nd Gear
QU10052 1-2 Shift Fork
QU10061 Premium Bearing and Seal Kit 1992-1995 GM 4x4
QU90020 NV4500 Manual Transmission Oil
TM1003 NV4500 Shop Manual
V1003DVD NV4500 Overhaul Video
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:
1992-1994 C1500, K1500, C2500, K2500, C3500, C3500HD, K3500 with NV4500 5 Speed