transmission

Transmission Oil Cooler

for 2006 Dodge Viper 8.3L V10 · RWD

Difficulty

Moderate

Time

2.0 h

Tools

Steps

🔧Does this apply to your car? On most cars the transmission cooler is built into the radiator side tank, not a separate part — this job most likely doesn't apply to your vehicle (cooler service happens with radiator replacement). Standalone auxiliary coolers are typically found on trucks, vans, and vehicles with a tow package.

✓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.

Remove and replace the transmission oil cooler assembly, including draining transmission fluid, disconnecting cooler lines, and installing a new cooler with fresh fluid.

Warnings

⚠Transmission fluid may be hot if vehicle has been recently driven. Allow at least 30 minutes cool-down time.

⚠The transmission oil cooler is mounted low and may contact road debris. Inspect for damage and leaks before beginning work.

ℹ️The 2005 Viper uses a Tremec T56 6-speed manual transmission. The oil cooler is an auxiliary unit separate from the main radiator.

Tools required

Floor jack and jack standsEssential

Drain pan (minimum 6 quart capacity)Essential

Socket set (metric)Essential

Line wrench set (flare nut wrenches)Essential

Torque wrenchEssential

Flathead screwdriver

Shop ragsEssential

Safety glassesEssential

Nitrile gloves

FunnelEssential

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

Parts

Transmission oil cooler × 1 — Use OEM specification or equivalent
Transmission cooler line o-rings × 2 — Use OEM specification
Transmission fluid filter (if applicable) × 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 GL-4 (manual transmission) — 4 qt

Preparation

Park vehicle on level surface and engage parking brake.
Allow transmission to cool if vehicle was recently driven (minimum 30 minutes).
Raise front of vehicle and support securely on jack stands at manufacturer lift points.
Place drain pan beneath transmission oil cooler location (driver side front of transmission case).
Have shop rags ready to contain fluid spills during line disconnection.

Procedure

1
Drain transmission fluid
Locate the transmission drain plug on the bottom of the T56 transmission case. Using the appropriate socket, remove the drain plug and allow fluid to drain completely into the drain pan. This will take 5-10 minutes for complete drainage. Inspect the drain plug and washer for damage.
2
Locate transmission oil cooler
The transmission oil cooler is mounted on the driver side of the vehicle, forward of the transmission case and typically secured to the frame rail or crossmember. It is a small finned heat exchanger unit separate from the main radiator. Identify the two transmission cooler lines (inlet and outlet) connected to the cooler body.
3
Disconnect cooler inlet line
Using a line wrench to prevent rounding, loosen the fitting connecting the inlet line to the transmission oil cooler. The fitting is typically a flare nut style connection. Once loose, carefully unthread by hand and allow residual fluid to drain into the pan. Cap or plug the line end to prevent contamination.
⚠Use a line wrench (flare nut wrench) rather than standard wrench to prevent damage to soft aluminum fittings.
4
Disconnect cooler outlet line
Repeat the process for the outlet line. Using the line wrench, loosen and remove the fitting connection to the oil cooler. Allow residual fluid to drain and cap or plug the line end.
5
Remove cooler mounting hardware
Locate the mounting brackets securing the transmission oil cooler to the frame rail or crossmember. Remove the mounting bolts securing the cooler assembly. There are typically 2-3 mounting bolts holding the cooler bracket in place.
6
Remove old transmission oil cooler
Once all mounting hardware is removed, carefully lower the transmission oil cooler assembly from its mounting location. Inspect the cooler for external damage, fin condition, and evidence of leaks. Check mounting brackets for cracks or fatigue.
7
Prepare new transmission oil cooler
Unpack the new transmission oil cooler and inspect for shipping damage. If the cooler came with new o-rings or seals, replace the old o-rings on the cooler line fittings. Lightly lubricate new o-rings with clean transmission fluid before installation. Transfer mounting brackets from old cooler to new unit if necessary.
8
Install new transmission oil cooler
Position the new transmission oil cooler into the mounting location. Align the mounting bracket holes with the frame rail or crossmember mounting points. Hand-thread the mounting bolts to secure the cooler in position, then torque to specification.
9
Reconnect transmission cooler lines
Remove caps or plugs from the transmission cooler lines. Thread the inlet line fitting into the new cooler by hand to avoid cross-threading. Once hand-tight, use the line wrench to snug the fitting. Repeat for the outlet line. Ensure both fittings are properly seated and not over-tightened, as this can damage the aluminum threads.
⚠Do not over-tighten aluminum cooler fittings. Hand-tight plus 1/4 turn with line wrench is typically sufficient.
10
Reinstall transmission drain plug
Clean the transmission drain plug and inspect the crush washer (if equipped). Install a new crush washer if the original shows deformation. Thread the drain plug into the transmission case by hand, then torque to specification.
11
Refill transmission with fluid
Locate the transmission fill plug on the side of the T56 transmission case. Remove the fill plug. Using a fluid pump or funnel with extension tube, add the factory-specified manual transmission fluid (verify exact spec and capacity in the 2005 Viper service manual) until it begins to flow from the fill hole. The transmission is filled when fluid reaches the bottom of the fill plug hole. Reinstall the fill plug and torque to specification.
ℹ️The T56 manual transmission uses 75W-90 synthetic GL-4 gear oil, NOT ATF. Using incorrect fluid will cause transmission damage.
12
Check for leaks
Lower the vehicle from jack stands. Start the engine and allow it to reach operating temperature. With the engine idling, inspect all transmission cooler connections for leaks. Check the cooler line fittings at both the cooler and transmission case. Look for drips or seepage. Shut off engine and perform a final visual inspection underneath the vehicle.

Reassembly

Ensure all cooler line fittings are properly tightened but not over-torqued.
Verify transmission fluid level is correct at the fill plug hole.
Double-check that all mounting bolts are torqued to specification.
Dispose of used transmission fluid according to local environmental regulations.

Verification

Start engine and verify no leaks at transmission oil cooler connections after reaching operating temperature.
Test drive vehicle through all gears to circulate fluid through the cooler system.
Re-check fluid level after test drive and top off if necessary.
Inspect cooler mounting for secure attachment with no movement or vibration.
Monitor transmission temperature gauge (if equipped) to ensure proper cooling function.