QU10331 NV4500 1st and 2nd Gear Downshift Inhibitor Block is a genuine NVG part made for the1-2 Downshift Inhibitor on 1992-1994 GM NV4500 1-2 Synchro Assemblies with 6.34:1 1st gear ratios. Sold individually. Order four blocks per transmission.
Also see QK1085 Downshift Inhibitor Spring and Block Kit
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: Downshift Inhibitor
Interlock Matching Parts Lubricants, Sealants, Threadlockers NV4500 Tools Applications
Tech Note 1: Downshift InhibitorThe downshift inhibitor feature uses centrifugal force to prevent high rpm downshifts from 3rd to 2nd and 2nd to 1st. It was only used on early production transmissions. It is possible to eliminate this feature by removing the 4 synchronizer blocks and 2 springs from the 1-2 synchro assembly. This feature is more important for 1992-1994 wide ratio GM models with 6.34-1 1st gear than it is for Dodge and GM transmissions with 5.61-1 first gear ratios. Tech Note 2: InterlockThe 1-2 shift interlock feature, which was used on 1992-1994 GM transmissions with 6.34: 1st gear ratio, was designed to prevent high speed downshifting 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 are 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 3: Matching PartsMatching Parts for QU10331 Shift Interlock Block:QU10333 Spring, 2nd Gear Downshift InhibitorQU10332 Spring, 1st Gear Downshift InhibitorQK1085 1-2 Downshift Inhibitor Parts KitQU10081 1-2 Synchro SliderQU10215 1st-2nd Synchro Assembly with Shift InterlockQU10002 Synchronizer Ring, Center FrictionQU10014 Synchronizer Ring, Inner SteelQU10015 Synchronizer Ring, Outer SteelQK1103 Snap Ring Kit, 1-2 SynchroQU10075 39 Tooth Mainshaft 1st GearQU10035 37 Tooth Mainshaft 2nd GearQU10052 1-2 Shift ForkQU90020 NV4500 Manual Transmission OilTM1003 NV4500 Shop Manual Tech Note 4: Lubricants, Sealants, ThreadlockersEarly 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 TransmissionsQU90020 NV4500 Manual Transmission Oil QU90003 Anaerobic SealantQU90006 3.35 oz Ultra Black RTV SealantQU90005 0.5 oz Ultra Black RTV SealantS24200 6ml ThreadlockerS9978 1 gram ThreadlockerQU90003 Anaerobic SealantQU90006 3.35 oz Ultra Black RTV SealantQU90005 0.5 oz Ultra Black RTV SealantS24200 6ml Medium Strength Blue ThreadlockerS9978 1 gram Medium Strength Blue ThreadlockerS9979 1 gram High Strength Red ThreadlockerS24026 High Temperature Threadlocker for Mainshaft Nut
Tech Note 5: NV4500 ToolsNeed 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.
TOOLS for SPECIFIC NV4500 MODELS
Component 23 SplineDodge 4x4NV4500LD 29 SplineDodge 4x4NV4500HD 30 SplineDodge 4x2NV4500LD 31 SplineDodge 4x2NV4500HD 32 SplineGM 4x4 35 SplineGM 4x2
Mainshaft Nut QT2002 QT2001QT2036 QT2002 QT2001QT2036 QT2002QT2028 1-1/2" HexSocket
Mainshaft Holding NLA QT2000 NLA QT2011 N/A N/A
5th Gear NutTorx® Cross Bolt N/A QT9205 N/A QT9205 N/A N/A
Output Seal Installer N/A QT1801 N/A QT2058CALL 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
CountershaftFront 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
Applications:Chevy and GMC:All with NV4500 5 Speed Manual Transmission: 1992, 1993, 1994
Phone:
406-384-0270
Email:
sales@torqueking.com
Location:
7727 S Leopard Ave,
Billings
Montana
59106
