Pete Trasborg
Brand Manager, Jp
We've had our '01 TJ in the fleet for 10 years now. Way back when we ordered it, the Dana 44 rear axle was the big thing to get. Historically, a Dana 44 was the last axle any Jeep would need, and we figured that would be the case for the TJ. When we ordered Red in 2000, not many had blown up or dissected the TJ Dana 44 rearend.
We now have about 150,000 miles on our TJ, and we've been fighting to keep the rearend together and leak-free for 100,000 miles of it. We have been through three different aftermarket lockers, countless axleshaft seals, and we recently blew the ring and pinion up. Our initial reaction was to rebuild it again, but after some quick measurements, we found the axlehousing was bent and that the price of a rebuild wasn't attractive at all. As it turns out, the TJ Dana 44s really aren't that much better than the Dana 30 and Dana 35 they replace. The big increase in strength comes from the ring and pinion and the carrier, but this strength is often negated by the weak housing and tubes. Much of that stuff probably popped because of the weak flexible housing.
Since this wasn't a newly-built Jeep, we needed to take what was already there into consideration. The front axle is stuffed with 4.56 gears and an ARB Air Locker. The wiring and most of the air lines are still present for the rear axle from a previous install, so it would be easy to put an ARB in the rear and our gear ratio was already chosen for us.
It became a game of whether to straighten the axle we had by retubing it or ordering a new one from one of many quality aftermarket vendors. Thinking there would be a big difference in cost, we considered several axle options. Here is what we found.
Rebuild
This Jeep is a daily-driver/weekend warrior and we don't really need Dana 60s in it, but we do need something better than a stock Dana 44. If we were to keep the TJ Dana 44, we'd need to beef it up. We'd re-tube it and then put a 3/16-inch TnT Customs truss with optional mounts and coil buckets on it to keep it from bending again. It would get an ARB Air Locker, 4.56 gears, and would need all new brakes and seals. Currie Enterprises does some good work rebuilding axles, so we'd drop the whole pile of parts off with them. This is what it would cost us to have Currie put our rear back to usable shape using TnT parts and bearings and seals from Randy's Ring and Pinion.
Pros: •Making the most of what we already have on hand •Truss will fix the bending issue
Cons: •Basically the same Dana 44 axle we've already destroyed several times •Does very little for gear strength •The splines on our stock shafts already have a bit of the twisted-barber-pole effect
Mopar New-Generation 44
The Mopar Dana 44 is a great solution for the TJ owner looking for a bolt-in solution that comes with a warranty and can be purchased at your local Jeep dealership. It comes with 1.41-inch 32-spline shafts that are drilled for both the stock TJ bolt pattern and the JK bolt pattern. The tubes are 31/4-inch diameter 5/16-wall and the brackets are made from heavy-duty 3/16-inch steel. Compare that to the 3-inch-diameter, 1/4-inch-wall and 1/8-inch-thick bracket on the stock axle. The ring gear is bigger (up to 8.8 inches from 8.5 inches) and features a longer tooth profile.
The pinion is 1/4-inch larger in diameter and the pinion head is much larger for any given gear ratio. The longer tooth profile and larger pinion head diameter means way more tooth contact than on our current Dana 44. The axle includes the factory electric locker which solves our desire for a selectable locker. The unit is only available at your dealership with 4.10 gears (PN 51552527), but Dynatrac is an authorized Mopar dealer and can install any gears you want, at which point it becomes a Dynatrac Trail Series 44.
Base axle price
$4,120
4.56 gear upgrade
$250
Total (MSRP)
$4,370
Pros: •Dealer availability (free shipping!) •Larger shafts •121/2-inch disc brakes fit 15-inch wheels •Big strength increase over existing 44
Cons: •Potential locker disengagement problems •Only available in 4.10 gears from dealer
Junkyard 9-Inch Axle
It would be really easy for us to just go down to the local junkyard and nab a 9-inch axle out of '74-'86 Ford truck, which would get us 31-spline axle shafts, stronger gears, and an axle that is easily modified. Again, we'd have it narrowed and regeared at Currie Enterprises and we'd be out the door at bargain basement prices. Or so we thought. It turns out that the junkyard build would be right around the same price as rebuilding our 44. The lower pinion of the 9-inch would probably pose problems with our lifted TJ and going to a high-pinion housing throws the bargain-basement theory out the window. However, Currie Enterprises feels the stock sheetmetal housing leaves a little to be desired in the strength department, and we would still have to have the TJ suspension bracketry installed before we could bolt it in under our Jeep. As with the rebuild, these things can add up fast.
Junkyard axle
$150
Narrow housing and reinstall housing ends
$140
Shorten shafts
$130
Master Rebuild Kit
$188
ARB Air Locker
$910
4.56 gears
$200
Gear and locker install
$175
Currie heavy-duty TJ suspension brackets
$400
Install brackets
$100
Square tube truss and install
$400
Total
$2,793
Pros: •Stronger gears •Common centersection parts
Cons: •Custom axleshaft lengths •Potential for low-pinion being too low •Still have hidden costs in rebuild, such as brakes and seals •Not all factory shafts are able to be shortened
Currie F9 Housing
The Currie F9 fabricated 9-inch housing is the next step forward in the evolution of the 9-inch axle. A press-formed and welded 3/16-inch steel plate housing combines with a 3/8-inch face and is way stronger than any stock 9-inch housing ever made. The first bend in the housing is at the centerline of the axletube, so unless you run your rearend with the yoke parallel to the ground, you will gain ground clearance by rotating it (up to 20 degrees). The F9 housing accepts up to 4-inch-diameter axletubes, and like all 9-inch rearends, is ultra-customizable. If you have a three-link, you can weld your brackets to this housing just like any other piece of steel. A truss can be added for the ultimate in bend resistance and it can be easily upgraded to 35-spline axleshafts for Dana 60-like strength in a much lighter and more compact package. The F9 housing for the TJ includes the heavy-duty Currie brackets, 3x0.250-inch-wall axletubes, both TJ and CJ bolt patterns, and is 61 inches wide overall. The prices below are for all new parts, but we could easily knock some coin off the bottom line by providing some junkyard parts we've got hanging around.
Currie F9 TJ assembly
$2,150
Currie 9-Plus centersection with 4.56 gears, 31-spline ARB Air Locker
$1,550
11-inch Drum Brake Kit
$390
Total
$4,090
Pros: •Lightweight •Good ground clearance •Can upgrade to larger axleshafts later if needed •Lends itself well to custom suspensions.
Cons: •Same low-pinion concerns as the junkyard axle •Can be upgraded with a high-pinion center section, but that impacts the price
G2 Model 44 Axle Assembly
The Dana 44 axle assembly built by G2 and sold by 4WD Hardware is a great alternative to rebuilding the stock axle. There is no assembly needed, just swap over your brakes and bolt it in. When you place the order you can request your choice of differential and gears (from 4.10 to 5.38). Differential choices include Detroit Locker, Detroit Truetrac, Auburn limited slip, Auburn ECTED, and ARB Air Locker. Shafts are 30-spline units by default, but can be upgraded to 33- or 35-spline for minimal additional charge. Not all locker choices are available in all spline counts. The base price below includes the ARB Locker and 4.56 G2 gears already installed. This housing is basically the TJ Rubicon Dana 44 housing, but there are thicker tubes and mounting brackets available for an additional $400 (price not included below). Since our brakes are shot, we are including those costs for an apples-to-apples comparison.
G2 assembly with ARB Air Locker, 4.56 gears, and 33-spline axleshafts
$2,423
New brakes shoes and hardware
$75
New brake drums
$60
Total
$2,558
Pros: •Lower cost than rebuild for all-new parts assembled •Larger axleshafts than stock for almost no additional money
Cons: •Still a TJ housing, so it is possible after abuse we'd have all the same issues we have now
Dynatrac Trail Series 60
Made in the USA, the Trail Series Dana 60 from Dynatrac provides a huge increase in strength with a minimal increase in price. The Dana 60 has a much larger 93/4-inch ring gear. The Trail series is Dynatrac's budget Dana 60, and though it is available with tons of options, once you start adding things, you could almost get into a ProRock 60 with its 30-percent increase in ground clearance and much beefier housing. That's not to say the Trail Series is a slouch, the Trail Series 60 comes with 35-spline, 11/2-inch-diameter axleshafts that won't even know our puny 35-inch tires are there. It is available in 601/2- and 631/2-inch widths and comes with 13-inch diameter disc brakes. Price below is a plain-Jane Trail 60 with no options except for an ARB Air Locker and 4.56 gears.
Base axle price
$4,390
Total (MSRP, can likely be found cheaper)
$4,390
Pros: •Hell-for-stout •Huge brakes help with stopping.
Cons: •Big brakes won't fit a 15-inch wheel •3/4-inch loss in ground clearance as compared to a Dana 44 which is like going from a 35-inch tire to a 33-inch tire •Heavier than a Dana 44 and has more parasitic drag, so it will take more fuel to move around
Currie Rock Jock 60
The Currie Rock Jock Dana 60 has a unique 60-degree angled cover to increase ground clearance and keep the cover from being peeled back by rocks. The Rock Jock is available in cast iron or aluminum to cut the weight closer to Dana 44 levels. Lubrication is provided by both an upper and lower oil valley to keep bearings and gears cooler. The same metal found in front-end loader buckets is used to fashion a skidplate for the housing and the housing runs a common high-pinion Dana 60 93/4-inch ring and pinion. The price below reflects a ductile-iron Rock Jock in an effort to keep costs down and make it more comparable to others in this story. That includes the Rock Jock centersection, 3-inch-diameter axletubes, 35-spline 11/2-inch axleshafts and your choice of brakes, differential cover options, and gearing selection. We added the 4.56 gears and ARB Air Locker for comparison's sake and picked the drum brakes. Explorer discs with a built-in parking brake and Wilwood discs are available and the online calculator makes it very easy to add and remove options until you've got a price you like.
Ductile Iron Rock Jock for TJ
$1,470
Axle package
$450
ARB Air Locker
$880
4.56 gears
$260
Master install kit
$126
Setup labor
$175
11-inch drum brake kit
$350
Heavy steel differential cover
$50
1310-series yoke
$60
Assembly charge
$50
Total
$3,871
Pros: •So heavy-duty it won't even know we are beating on it •Differential cover pointing up makes for worry-free rock basing
Cons: •More parasitic loss and weight can lead to lower gas mileage (aluminum centersection is available for about $70 more) •Rotated cover might create interference if we ever lower the Jeep
Which one?
We can't tell you what axle you need to choose to put in your Jeep. You need to weigh all the options, figure out your budget, and determine what size tire you are going to run. You also need to take your driveshaft angle into account and all the other little things that come into play.
If we didn't have a good shop nearby that could retube our existing axle, it wouldn't even be an option because shipping quickly negates any possible cost savings. Even at that, the junkyard 9-inch build and rebuilding of the rear axle don't really take into account all of our problems. Our shafts are starting to twist, which makes the 33-spline G2 axle more attractive, but then we get back to the blown-up ring and pinion; it makes us lean toward something stronger than a TJ Dana 44 ring and pinion. Which do we go with? You'll just have to tune in next time.
