Ultimate Jeep Dana 30 - Detroit Soft Locker
Ultimate Jeep Wrangler Dana 30 - Detroit Soft Locker
Short Cuts
by: Ron Hollatz
Feb, 2000

While it's apart let's put in a Detroit Soft Locker

When I first upgraded my Dana 30 in 1997 I chose to put in a Detroit Truetrac. My Wrangler was my daily driver on the often-wet roads of Seattle and I didn't want to take any chances. The Truetrac is a gear driven (no clutches) toruqe biasing limited slip differential that gives you extra traction when needed without the sometimes unpredictable nature of a full locker. I did get a small amount of steering feedback from the front end, but not enough to cause any problems. This setup worked especially well on the snowy roads in Minnesota. While off-road I had the extra traction I needed unless one wheel was up in the air. Usually I could apply some brake and get both wheels going, but once I started running the 4+ trails at Moab I decided I needed more.

In my opinion, there are currently 2 choices when it comes to a heavy duty locking differential, the ARB Air Locker and Tractech's Detroit Soft Locker. I really didn't consider the spider gear replacement lockers since I would have had to purchase a carrier as the Truetrac replaces the stock carrier. The added cost of the new gear carrier (for me) eliminated much of the price advantage of the spider gear replacements. The Detroit Gearless Locker sounded interesting, but a cutaway sample a vendor had at Moab kept seizing up and I really didn't want to deal with the possible headaches of a new product.

The ARB vs. Detroit debate is one that has raged for years. The big advantage of the ARB is the ability to turn the locker on and off from the driver's seat. This is really helpful when tight turns are needed on the trail while in 4WD and on the street. The big disadvantage is this setup requires air lines, a compressor, switches, and solenoids to operate. A failure of these items would leave you with essentially an open differential. A professional should install the ARB so that everything works as designed.

The Detroit Soft Locker is just a heavy-duty replacement carrier with no other parts required. My Atlas transfer case allows me to shift between 2WD and 4WD low giving me some of the same functionality as the switch on the ARB (for the front axle). With the hubs locked and the transfer case in rear 2WD low the Detroit seems to have no effect. I had been pleased with the performace of the Detroit Soft Locker that John Nutter and I had installed in my rear Dana 44 previously, so the decision was an easy one for me.

We had learned when going from one Detroit product to another the ring and pinion settings were not really affected. We checked the preload and backlash along with running a gear pattern and they were dead on. These measurements are still critical and should be done whenever differential work is done. The installation was pretty simple (once we got the old one out, see above) - as long as you have a basic understanding of ring and pinion settings. If you haven't set one up before I'd recommend having a professional do it or find someone like a club member who will let you participate. I managed to get everything put back together for The 1999 Dakota Territory Challenge and the axle performed flawlessly. I wish I could say that for all my modifications.

So was it worth it?

In hindsight I should have just upgraded to a Dana 44 at the start of this project. There isn't that much of a price difference between rebuilding a Dana 30 vs. a Dana 44 if you use the same level of components. There are a couple options for junkyard axles which will fit in a 1987-1995 YJ with a bit of modification, but in the end won't save you a lot of money. I know I'll get mail telling me someone swapped in a Dana 44 for $200.00 but I wouldn't feel comfortable unless I knew every component was perfect.If I were building a Dana 44 I'd want to do the same upgrades as I've done to the Dana 30.

Another thing to remember is the Wrangler 5" on 4 1/2" bolt circle was not available on any front Dana 44 that I know of, so the bolt circle needs to be changed on either the replacement axle or the rear axle. If you are replacing both the front and rear axles this is not necessary, but it is something to keep in mind. Some steering modifications may also be required to keep the proper steering geometry.

The 1996 to present Wrangler TJ is another story. With its coil spring suspension, major fabrication is required to replace the Dana 30 with a heavier duty axle. With the modifications I have done, my Dana 30 should be as strong as a stock Dana 44 from another vehicle. Its weakest points would be the size of the ring and pinion and possibly the steering knuckles. In my estimation, the Warn shafts are at least as strong as stock Dana 44 shafts and so far the hubs have held up fine. Some may question is the strength of the Dana 30's axle housing, but a friend of mine is working a compression style axle truss for the top of the housing. That and some heavier steering components should make the two axle housings comparable in strength. I love the added traction of The Detroit Soft Locker, but I would not recommend this on a street driven Jeep unless you have locking hubs.

These modifications are not for the faint of heart or pocketbook. The hubs, locker, and axle shafts cost me around $1500.00 in parts and all together I have over $2000.00 invested in the axle. This would go a long ways toward paying for much of a custom Dana 44 from some of the after market custom axle builders like Dynatrac or Foothill Off-Road. The deciding factors for each person should really be what type of wheeling you plan to do, and what you can afford (and if you can afford it all at once, or need to spread it out a bit). I feel the Dana 30 axle with a few modifications will hold up to all but the most extreme trails. I'm just going to keep telling myself this and ignore the Wagoneer Dana 44 sitting in the backyard.


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