Jeep JK Fluid Differential Change: How Much Transmission Fluid Do You Need?

Whether you're an occasional off-roader or you're on the trails every week, proper auto care is essential to your 4x4's performance. Several systems, including its transmission. work together to supply the power and motion needed to cover your ground. 

What Oil Goes in Jeep Differentials?

You've probably noticed that many people use the terms "transmission fluid" and "differential fluid" interchangeably. Maybe you do, too. While this isn't a huge deal, it is helpful to understand the differences between the two plus how each one benefits your vehicle. And that calls for a quick review of manual and automatic transmission styles. 

While offroaders have their preferences between manual and auto transmissions, both are more than capable on the trails. Manual transmissions require you to do all the work, so they contain a shifter and aclutch petal plus two shafts and two gears. Automatic transmissions employ a torque converter, so they contain more moving components than manual versions.

You may commonly hear differentials referred to as gearboxes, which are part of the transmission assembly as a whole. Manual gearboxes put out a lot of friction and heat, so differential oil must lubricate the gears to cut down on both and avoid premature failure. That's why differential oil must possess key characteristics to effectively do its job: superior heat resistance,high viscosity and the ability to withstand high pressure

You can see how these properties differ from standard transmission fluid. First, transmission oil must be low-viscosity to flow easily through the entire assembly. Transmission fluid must also be heat-resistant, but not to the same degree as gear oil. Finally, anti-foaming qualities stop air bubbles from getting into the assembly and negatively impacting transmission performance 

Most Jeep JK Wranglers use 80W-90 differential oil, but you should check your specific owner's manual for details. Some popular choices in gear oil for Jeep JK Wranglers include Yukon Gear and Axle, Mopar and Royal Purple. 

Jeep JK Fluid Capacities

Every vehicle has different fluid requirements for its engine, transmission/differential, coolant, transfer case, axles, power steering and brakes. The Jeep JK series, sold between 2007 and 2018, is no different. Knowing your 4x4's fluid needs can help you meet them and ensure the best possible performance on any terrain. With Jeep JK differential oil, fluid capacity depends on the type of axle inside your vehicle:

• Dana 30: 2.1 pints (1 liter)
• Dana 35: 3.5 pints (1.7 liters)
• Dana 44 Front: 2.7 pints (1.3 liters)
• Dana 44 Rear: 4.75 pints (2,25 liters)

Changing the Fluid

So now that you understand how differential fluid affects your Jeep's performance, you're probably wondering how often you should change it. Most drivers can refer to their owner's manuals for guidance. American auto manufacturers typically recommend intervals ranging between 30,000 and 60,000.

Your manual may include a "Schedule B" maintenance routine for heavy driving. Many off-roaders find that this schedule works well for their Jeeps. Typically, this means changing your differential oil every 15,000 miles. 

Step-by-Step Instructions

If you have beginner-level auto care skills, you can probably change your differential fluid. You will need some essential tools: a ratchet and socket set, a catch pan, a gasket or gasket scraper, a jack with jack stands and a torque wrench. Depending on the vehicle, you may also need a gasket maker. You'll also need brake cleaner to clean leftover differential fluid out of the housing. 

Before getting started, you should choose a well-ventillated workspace. Differential fluid smells awful, but it also can make you very sick if you breathe in the fumes. Work either outside or in a garage with plenty of open windows and a box fan for proper air circulation. Also, park your vehicle on a flat surface and jack up the rear, securing it with jack stands and wheel chocks on the front. After this, you'll need to follow some simple steps:

• Remove the fill bolt or rubber plug, then drain the differential fluid into your catch pan.
• Take off the differential fill plug and cover bolts, then pry off the bottom cover of the housing. 
• After draining differential fluid, clean out the interior with brake cleaner.
• With your scraper, clear off any gasket remains from the differential cover and house mating surfaces. 
• Align bolt holes with the matching holes in the housing cover. After spraying on adhesive to fix it into place, bolt the cover back onto the differential.
• Pour the recommended amount of differential fluid through the filling port. You can also add limited slip additive, if required.
• Replace the filler bolt and tighten until secure. 

Maintenance and Jeep Performance

Proper differential care is key to your offroading experience. With the right type of fluid and replacement intervals, you can experience get the best possible performance from your Jeep.