QK1085 NV4500 1-2 Interlock Small Parts Kit

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QK1085 NV4500 1-2 Interlock Small Parts Kit for 1992-1994 6.34-1 1st gear ratio GM New Venture NV4500 5 speed manual transmissions with the safety interlock for 1st and 2nd gear. Will also fit 1992-1994 Dodge NV4500 models with the slotted 1-2 synchro hub.

QK1085
Interlock Small Parts Kit
$24.50
* Kits made up of multiple items may not show an inventory in-stock status but are almost always in stock!

tech note

The 1-2 interlock feature was used on 1992-1994 GM NV4500 models with the 6.34:1 1st gear ratio. The interlock is designed to prevent down shifting into 2nd or 1st gear at high mainshaft speeds. At higher speeds, centrifugal force pushes the flyweights against the 1-2 synchro slider so it can not be shifted.  I did find a few early Dodge and 1995 GM transmissions that also had this feature, but I suspect the interlock parts were added during a previous rebuild.

tech note

QK1085 Kit includes:
(4) QU10331 Blocks
(1) QU10332 Spring, 1st Gear
(1) QU10333 Spring, 2nd Gear

tech note

Matching Parts for QU10331 Shift Interlock Block:
QU10081 1-2 Synchro Slider
QU10215
 1st-2nd Synchro Assembly with Shift Interlock
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
QU90020 NV4500 Manual Transmission Oil
TM1003 NV4500 Shop Manual

tech note

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 Threadlocker
S9978 1 gram Threadlocker
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

tech note

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.

TOOLS for SPECIFIC NV4500 MODELS

Component 23 Spline
Dodge 4x4
NV4500LD
29 Spline
Dodge 4x4
NV4500HD
30 Spline
Dodge 4x2
NV4500LD
31 Spline
Dodge 4x2
NV4500HD
32 Spline
GM 4x4
35 Spline
GM 4x2
Mainshaft Nut QT2002 QT2001
QT2036
QT2002 QT2001
QT2036
QT2002
QT2028
1-1/2" Hex
Socket
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
CALL
Not Used Not Used
Tailshaft Bushing Remover and Installer Not Used Not Used Not Used QT2044 Not Used Not Used

TOOLS For ALL NV4500 MODELS

Countershaft
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

Application

Chevy and GMC:
1992-1994 NV4500 with 6.34:1 1st Gear Ratio