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How to Change Gear Oil in a Dodge RAM 1500

by John Walker

Dodge recommends you change the gear oil in the front and rear differential every 15,000 to 25,000 miles. Most Dodge differentials use a drain plug requiring a hex-head ratchet to remove. Some Ram 1500s require you to open the differential cover to drain the fluid. You should always remove the cover, and clean the area before filling. Most trucks use the same method for cleaning and refilling the differentials. Dodge recommends you use GL-5 SAE 75w90 gear oil on most Dodge Ram pickups unless your manual calls for 75w140.

Step 1

Place the oil bucket beneath the front or rear differential.

Step 2

Loosen the retaining bolts for the differential cover until you have a substantial gap between the bolt head and the cover. Crack the seal and allow the fluid to drain into the oil bucket.

Step 3

Remove the cover entirely and spray the parts with a brake parts spray cleaner. Allow the cleaner to drain off into the bucket.

Step 4

Replace the gasket. You may have to scrape off old gasket material with a scraper or screwdriver. Install the gasket, replace the cover. Hand-tighten all bolts and use the socket wrench to fully tighten them. Torque the bolts to 20 foot pounds of torque.

Remove the fill plug using a hex-head ratchet if a metal fill plug is present. Remove the rubber fill plug if equipped using a screwdriver. Fill the differential with SAE 75w90 gear oil until the oil level is flush with the bottom of the fill plug hole. A little line of fluid will run out when the gearbox is full. Replace the rubber or metal plug.


  • After the task, monitor the differential over the next few days for signs of leaks. The only leak possible would be if the gasket was not installed properly. Correct such if you notice leaks.

Items you will need

  • 10 pints of SAE 75w90 gear oil
  • Ratchet
  • Hex head ratchet
  • Oil bucket
  • Rag
  • Brake parts cleaner
  • Replacement gasket
  • Scraper or screwdriver

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