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Dodge 4WD NV4500 Transmission 5th Gear Repair Solution

Did you "lose" 5th gear in your 94-02 Ram 5 Speed NV4500 Equipped Ram Cummins?
The otherwise reliable Dodge NV4500 4x4 manual transmission has one fault, a tendency for 5th gear failure caused by the 5th gear retainer nut backing off, we have the solution.

The Fifth Gear lock nut retainer locks the nut to the spline on the main shaft. By doing this the retaining nut can’t back off.  Some customers have experienced as many as five failures until this retainer was installed. After installation of the lock nut retainer there have been no known failures.

This lock nut retainer is designed for the Dodge NV4500 4x4 transmissions with a 29 spline and 1½” main shaft. It is very simple to install as it slides over the output shaft spline and is easily indexed to the retaining nut. No special tools are needed to install and no costly transmission costs to pay. The unit should be installed by a competent mechanic but it’s very easy to do. If installing this retainer because of 5th gear failure, be sure to inspect the main shaft splines to make sure that no damage has been done by the break down. If damage has occurred be sure the transmission is repaired properly first.

Make this a regular part of all your 4x4 NV4500 rebuilds!

The NV4500 5-speed manual transmission often fails in fifth gear, even after installing a main shaft update kit. In some cases the same transmission can fail over and over again.  This retainer locks the nut into the mainshaft spline.
Lock nut retainer prevents fifth gear failure/loss caused by the 5th gear retainer nut backing off in the Dodge NV4500 transmission.

 *This Kit Will NOT work on 2wd transmissions*


  •     No need to purchase a mainshaft update kit or a new lock nut (works with original nut or any after market nut)
  •     No special tools needed (just index the retainer on the spline and into your existing locknut)
  •     Ensures that the fifth gear isn't lost due to the retainer nut coming loose and backing off
  •     Helps to keep the transmission running smoothly

Features and Specs

  •     The lock nut retainer is made of durable Chromoly steel
  •     Steel lock nut is cylindrical and measures 1½” tall and 2 ½” in diameter
  •     There are four posts on the bottom measuring ½” tall and 7/40” wide
  •     The inner hole is lined with 29 splines that are ¼” thick; hole measures 1½” in diameter between the spline and 3/8” in diameter from spline to tip.
  •     Mechanic installs the lock nut on the transmission to keep fifth gear nut from coming loose.

Part number: NV45LNRET

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