transmission

Manual Trans Fluid Change

for 1994–2007 Dodge Ram 2500 5.9L I6 Cummins Diesel · 4WD

Difficulty

Easy

Time

36 min

Tools

Steps

✓Fact-checked. Built from OLP's spec database, then independently fact-checked line by line with every correction applied. Master-tech sign-off by Chris Hackleman is queued. Cross-check torque values against the factory manual, and stop if anything looks unsafe. How our data is made.

This procedure covers draining and refilling the manual transmission fluid on a 1994-2007 Dodge Ram 2500 with the NV4500 or NV5600 5-speed manual transmission.

Warnings

⚠Transmission fluid may be hot if vehicle was recently driven. Allow adequate cooling time before starting work.

⚠Gear oil has a strong sulfur odor and can irritate skin. Work in a well-ventilated area and use gloves.

ℹ️The NV4500 and NV5600 transmissions are externally similar but have different fluid capacities. NV4500 holds approximately 4 quarts, NV5600 holds approximately 4.2 quarts.

Tools required

3/8" drive ratchetEssential

3/8" drive extension setEssential

17mm socket or wrenchEssential

Fluid pump or transfer pumpEssential

Drain pan (minimum 5 quart capacity)Essential

Torque wrench (10-50 Nm range)Essential

Jack and jack stands rated for vehicle weightEssential

Wheel chocksEssential

Nitrile gloves

Shop rags

Wire brush

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Parts

Drain plug washer (if separate washer type) × 1 — Use OEM specification
Fill plug washer (if separate washer type) × 1 — Use OEM specification

As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Fluids

75W-90 synthetic gear oil — 4 qt

Preparation

Park vehicle on level ground and engage parking brake firmly
Place wheel chocks behind rear wheels
If vehicle was recently driven, allow transmission to cool for at least 30 minutes
Raise front of vehicle using jack and support securely on jack stands at frame rails
Verify vehicle is stable and level for accurate fluid filling

Procedure

1
Locate transmission drain and fill plugs
From under the vehicle, identify the transmission case. The drain plug is located on the bottom of the transmission case. The fill plug is located on the driver's side of the transmission case, approximately halfway up. Clean the area around both plugs with a wire brush and shop rag to prevent contamination.
2
Remove fill plug first
Using the appropriate tool (many NV4500/NV5600 plugs accept a 3/8" drive ratchet directly in the square recess; verify plug type before starting), loosen and remove the fill plug from the side of the transmission case. Removing the fill plug first ensures you can refill the transmission after draining. If the fill plug is seized or damaged, address this before draining to avoid being unable to refill.
3
Position drain pan and remove drain plug
Place the drain pan directly under the transmission drain plug. Using the appropriate tool (many NV4500/NV5600 plugs accept a 3/8" drive ratchet directly in the square recess; verify plug type before starting), slowly loosen the drain plug. Once loose, quickly remove it by hand and allow the fluid to drain completely. This may take 5-10 minutes. Inspect the drain plug and washer for damage.
4
Clean and inspect drain plug
Once fluid has completely drained, clean the drain plug threads and sealing surface with a shop rag. Inspect the drain plug washer (if equipped). Some Ram 2500 manual transmissions use a tapered plug without a separate washer, while others have a crush washer. Replace the washer if it is a separate component. Clean the drain plug hole threads in the transmission case.
5
Install drain plug
Install a new washer on the drain plug if applicable. Thread the drain plug into the transmission case by hand to avoid cross-threading. Tighten the drain plug to the manufacturer-specified torque (verify spec for your transmission; typically in the 20-30 ft-lb range) using a torque wrench.
Torque spec
Drain Plug34 Nm (25 lb-ft)
6
Prepare fluid pump and new gear oil
Set up your fluid pump with the intake hose in a container of new manufacturer-specified gear oil (NV4500 requires GL-4 spec fluid such as MOPAR/Castrol Syntorque 75W-85; NV5600 uses MOPAR synthetic 75W-90 — verify the correct spec for your transmission). Insert the discharge hose into the fill plug hole on the side of the transmission. Ensure the pump is primed and ready to transfer fluid.
7
Fill transmission with gear oil
Pump gear oil into the transmission through the fill hole until fluid begins to flow out of the fill hole opening. The transmission is full when fluid reaches the bottom of the fill plug hole. For NV4500 transmissions, this is approximately 4 quarts. For NV5600 transmissions, expect approximately 4.75 quarts. Allow excess fluid to drain back out until flow stops.
8
Install fill plug
Clean the fill plug threads and inspect the washer (if equipped). Install a new washer if applicable. Thread the fill plug into the transmission case by hand, then tighten to specification using a torque wrench.
Torque spec
Fill Plug34 Nm (25 lb-ft)
9
Clean up and lower vehicle
Wipe down the transmission case to remove any spilled gear oil. Inspect both drain and fill plugs for leaks. Remove jack stands and carefully lower the vehicle to the ground. Dispose of used gear oil properly at a recycling center or parts store that accepts used oil.

Reassembly

No disassembly was required for this procedure

Verification

Start the engine and allow it to idle for 1-2 minutes
With the clutch pedal depressed, shift through all gears to circulate new fluid
Turn off engine and check both drain and fill plugs for leaks
After initial test drive (10-15 miles), recheck both plugs for leaks with vehicle on level ground
Monitor for any unusual transmission noises or shifting difficulties over the next several days