Rear Axle Upgrades and Diff School – Part One – Stock Removal, Gear Oil, and Wear

Rear Axle Upgrades and Diff School – Part One – Stock Removal, Gear Oil, and Wear

I decided to call this “Diff School” because when I was having my rear axle upgraded at World Tour Off Road in Annapolis, MD, Paul Warren spent a lot of time sharing his knowledge with me. I was expecting to cut most of this out of the final edits so I could put together a concise gear and axle swap video… but I realized that some of you, and I understand it won’t be all of you, may find this as interesting as I did, and could perhaps get some value out of the small tidbits of information Paul passed to me along the way. He allowed me to hang out and film the entire process…but didn’t stop there… he actually stopped to teach along the way. Consider this your gear school!

These rear axle upgrades come as part of the Dynatrac Trail Leader Package. Here is the info on that package:

We created the Trail Leader Axle Package™ for Jeep JK owners who enjoy moderate off-roading and want reliable drivetrain durability after upgrading to 33- to 37-inch-tall tires. This package gives you all the Dynatrac strength and durability you need without requiring wheel changes or other costly upgrades that simply aren’t necessary for the type of off-roading you do.

The Trail Leader Axle Package™ includes an assembled ProRock 44™ Unlimited front axle with 1/2-inch thick axle tube walls complete with Dynatrac HD Rebuildable Balljoints, Dynatrac Pro Series™ diff cover, front Dynatrac axleshafts, ARB air Locker and ring-and-pinion gear set. Move your factory spindles and brakes onto this new front axle and the assembly is ready to bot into your Jeep! The package also includes the following to upgrade your factory Dana 44: Dynatrac JK44 Axleshaft Upgrade Kit™, 35-spline ARB Air Locker, Dynatrac Pro Series™ diff cover, ring-and-pinion gear set and a set-up kit..

NOTE: The Trail Leader Axle Package™ is only for non-Rubicon Jeep JK models. If you own a Rubicon model, please have a look at our ProRock 44 front axle housing upgrade and our Serious Performance Axle Set™.

What You Get:

ProRock 44™ Unlimited Front Axle

Dynatrac-exclusive patented ProRock® nodular-iron, high-pinion ProRock 44™ centersection with control arm bushings installed.

Best-in-class ground clearance and more ground clearance than a factory Dana 30.

3-inch-diameter x ½-inch-thick wall tubing that is 3 times stronger than any stock JK Dana 44 housing.

Dynatrac’s U.S.-made forged, double-heat-treated 1350 axleshaft assemblies are included. You get our latest inner and outer 4340 shafts with new U-joints installed.

Dynatrac HD BallJoints™ are already installed; the last balljoints you’ll ever need.

Includes our latest integrated raised track-bar and ram-assist steering mounting package. Dynatrac now offers the very best high-strength steering linkage and integrated ram-assist bracket in the industry.

Dynatrac precision-aligned, alloy-steel end forgings, 100% made in the USA.

ProRock 44™ Unlimited housing geometry for superior handling and optimal pinion and driveshaft angle for lifted JKs.

Rock-proof nodular-iron Dynatrac diff cover.

All HD suspension brackets are CNC laser-cut and professionally welded and installed, including high-mount track-bar bracket setup for lifted JKs with top-down mounted drag links and high-steering packages.

1350 yoke

ARB Air Locker

Axle includes your choice of available selectable lockers and 4.88, 5.13 or 5.38 gear sets.

Dynatrac 35-Spline JK44 Rear Dana 44 Upgrade Kit

Dynatrac 35-Spline JK44 Axleshaft Kit

35-spline ARB Air Locker (including bearing and shims)

Dynatrac Pro Series™ nodular-iron differential cover

Ring and Pinion gear set

Gear installation and set-up kit

All the strength your JK Dana 44 rear axle will ever need! This rear JK44 Axleshaft Bundle Kit increases the shaft diameter to from 30- to 35-spline. The shafts feature Dynatrac proprietary deep heat-treat for optimum yield strength (resistance to twisting) without making the axleshafts brittle. The shafts are U.S.-made, equipped with rolled splines and include new wheel studs, billet steel retainers, seals and all of the hardware that will be needed for installation. If you need more strength than this, then you need a Dynatrac ProRock® rear axle!

JK44 Axleshaft™ Features Include:

U.S. Made 35-spline axleshafts

New billet tone rings already installed on the axleshafts.

Dynatrac Billet Axleshaft Retainers with studs – Always insist on Dynatrac retainers. Our studs will not strip and spin like other retainers.

Axleshafts are drilled with BOTH wheel bolt patterns.

We install the studs for you in the right pattern when you order the kit.

This kit has the studs installed for the factory bolt pattern.

Rear axleshaft kit fits factory Dana 44 (not for the Rubicon version).

Axleshafts come complete and ready to install (no additional work needed) We do ALL the press work for you!!!

No modifications to housing is needed.

New axleshaft bearings and seals are included.


Blake S says:

did ya sell the gears ever?

Blake S says:

great video thanks for sharing! i have a 05 tj and broke some teeth on the pinion gear, never done differential work but im about to……once my research is done

Rich Beach says:

This is great stuff, looking forward to the rest of the videos!

rbohn1 says:

Well done! Loved seeing the full detail…especially by a master!

ApexPredator_JKU says:

Great series! I ended up going the same route. ProRock 44 up front, 35 spline RCVs & retained D44 in the rear, 35 spline G2 gold placers, DT diff cover & bridge for RK 3 link & ARB’s F/R…bout as good as it gets w/o going D60. The difference between 30/32 spline vs 35, side by side is impressive

Aaron Carter says:

Gee, thankyou so much! This is a massive help and so interesting. Just watched the dynatrac 44 upgrade too. I’m a newbie and these videos are huge in my learnings.

Dave M says:

Very informative video and well shot. THanks for taking the time to make it.

Remi Ramos says:

This was awesome! Thanks for sharing.

gakiganger says:

Best explanation ever


Very informative. Can’t wait for the next video

Mihail G says:

That’s why it’s much better dynatrack 60

Funky Dodo says:

Thanks for the video it’s very informative, the mechanic really explain everything good and simple.