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The greatest benefit of the dynatrac or the pre 99 setup is larger bearings spaced further apart. Inside the unit bearing they are all but back to back and this close spacing puts tremendous strain on the bearings. I had one fail with 90k but the other is still going at 120k. I don't have front ABS so the bearings have never been re-greased. I am running the stock rims and 265-16 tires. I use my truck to plow snow all winter and have had a Boss 8' plow on it for 8 or 9 years. Until the last couple years my truck spent most of the summers hooked to a trailer and routinely grossing 20k.
I installed warn hubs several years ago and run with them locked all winter. I only unlock if I plan to travel a long distance on the highway. I have never replaced the spindle bearings, only added some grease to them when I had it apart. Never had any axle wear issues but I have replaced both axle u joints a couple times.
The thumping noise when you turn the wheels tight with the hubs locked in is perfectly normal, it's the nature of this type of joint. I have had a solid axle 4x4 for over 30 years and this one is no different than any of the others. When you start feeling the thump or jumping then you need to steer out of the turn or you WILL tear something up, that is the signal that the joint has reached it's limits. Just because you are able to turn it tighter does not mean that you should, that is for 2 wheel mode.
If it is tearing things up then its probably something you are doing in the way you use it or inferior parts. Oversize tires and deep offset rims will destroy unit bearings, if you want to run these then the dynatrac is a must. If you are routinely hitting the steering stops with hubs locked or even worse under load in 4x4 I'm going to guess you found your problem.
I completely agree that the old spindle and bearing setup was much better, but not so much that I am willing to spend 2 grand to install it.
Well why cant we just get parts from a pre 99 Dana 60 axle and bolt them on to our axles? As far as I know the knuckles are still the same four bolt design so the spindle should bolt right on.... then use a pre D60 stub shaft on our axle shaft (same ujoint size) and use the bearings and hub from the pre 99 also? They are the same except for the unit bearing vs spindle setup
The 92-97 balljoint D60 knuckle will work but you would have to redrill the hub and rotor for the 8x170, you loose front ABS and IIRC the rotor is smaller.
I have the Dynatrac kit on my 00. Has worked great for the last ~8 years. It is much more durable than the stock setup especially if your running larger tires or lockers. You gain space between the bearings for better leverage so it's less likely to have a wheel come off which isn't all that common but can happen with the stock unitbearings. You also gain 35 spline outer shafts vs the stock 30 spline ones, that helps for large tires and lockers but also gives you larger lockouts.
Something is wrong here, it just doesn't make sense. When the hubs are locked the stub shafts are riding with the bearing, not free spinning inside of it on the needle bearings. The needle bearings and stub shafts shouldn't wear unless the hub is unlocked and they're not lubricated correctly.
Remember that there are hundreds of thousands of trucks on the road with this system, and most of them don't give people trouble like yours has. Most get at least a hundred thousand miles out of a unit bearing and will never replace a stub shaft.
I agree that something is wrong. I'm also willing to bet I did something wrong the last go around but about 4 years ago, I chunked up a large sum of money to Ford to have everything redone in the front axle. It only last about 2 years before trashing a bearing and once again wearing out a axle shaft. I'm wondering if my old factory auto lock hubs are to blame? They are the only part that hasn't been replaced.
I'd like to get home and tear the truck apart before ordering what I need and maybe taking another shot at it, however I work out in remote Alaska 6 out of 7 weeks, so my time at home is quite limited. During my month at home this winter, I will investigate again.
This thread has been a great discussion on it and I wouldn't shy away from the Dynatrac kit but it has reminded me to look it all over once more and make sure I'm not missing something obvious.
For the price they want I could buy nearly ten pair of aftermarket wheel bearings."
Funny that is how many I have bought in a couple of years and I do grease them with the tap that forces new grease outside the seals (http://www.riffraffdiesel.com/front-...k-off-fitting/). I remove and grease the axle support Torrington bearings as well. I use Timken and replace the knuckle seals and it has cost me more than a $1500 SpynTec kit. What I hate though is I cannot leave the hubs locked without getting the thumping sound when turning. Everything has been replaced.
"Who pays $2,000 to have to service and repack bearings every 30,000 miles? "
That is a privilege I would love to have!
This is on a 2002 F250 with the Dana 60 and it is only used for two passenger on-road use. No towing (took the hitch off even) and no hauling (bed looks new).
When I had new Yoko ATS 265/75R16 tires on the front I would consistently get a hum two weeks after re-greasing. HT tires now go a little longer. I have learned my lesson. The passenger side axle shaft cannot be properly supported by the factory design. http://quad4x4.com/ford60f1999-2004f250-350.html ("The Achilles Heel of the 1999-2004 era Ford Super Duty front axle is the way the axle shaft is supported. The inboard end of the inner axle shaft is anchored in the differential, but most of the axle shaft weight is borne by a smallish needle bearing in the wheel hub and by the lockout hub. If the needle bearing runs out of grease, the bearing will quickly chew up the outer axle shaft before you start to hear grinding noises.") tells you about it.
I never had this problem with my OBS trucks and Bronco's even when I crossed rivers with them (had to grease them of course).
I currently drive less than 5K miles a year and this sad saga continues. As a truck mechanic I would never discourage anyone from ditching the unitized junk that only helps the assembly line process.
Off the soapbox.
I did the same back in August 2008...never regretted it for a second. As retired military, we have family ALL OVER the USA. Who wants to have a front wheel bearing go out when you're 1000 miles away from your stuff! My right front wheel bearing started squealing, and I mean bad all at once. Happened late at night just as we were headed to BTS Tranny in Lead Hill AR. We'd just crossed the Poplar St Bridge in St Louis and was making a right hand turn onto I-44.....SQUEALLLLLLLL! Stopped, called a local roll-off and $250.00 later we were back in our driveway. I researched this kit and it made sense to me...if you're running big tires and mine are 35's...I think that configuration is harder on those front wheel bearings that already are compromised in my opinion, since the inner & outer are next to each other. I use Schaefers grease which holds up quite well and if they do need repacking, it's a great time to check/redo the brakes.
The only experience I have is wishing I went ahead and put it in when my first hub bearing went bad. I replaced both figuring that the other might not be far behind at a cost of over 1k. 2 years later, one of the replacement Moog bearings failed. It was still under warranty but I had to ship the defective one to them and wait for a replacement; unfortunately I had to have the truck back together so I had to buy another hub assembly. At this point, I'm nearly up to the cost of the Dynatrac kit. It would've been financially about even money but it would've saved me headaches. I do have a brand new in the box Moog hub though sitting on the shelf in the garage if I ever need one again. I think the truck is going to succumb to rust though before I use up any more hubs. Oh, I also have a lockout hub failing and the warn replacements are about 400 a pair; the only other choice is factory at 100 to 120 each depending where you buy it. This is an 07 truck. She's been without question the most expensive to own vehicle I've ever had. I bought used but for the money it's cost me, I could've had brand new and it hopefully wouldn't be rusting apart yet. The best improvement I made to the truck, bang for the buck wise, was to buy a used Camry to drive around in all the time. It really cut down on the breakdowns.
I’ll pile on: after 20 years of rebuilding and regearing Dana axles, I pulled apart my first Ford Dana 50 and I honestly thought pieces were missing. Who the hell would design an unsupported 3’ long 30 lb shaft of metal? Insane.
I converted my 99 dually to Dynatrac "free spin" kit about 8 years ago because one unit bearing was noisy and did not want to mess with unit bearings since I haul a pretty heavy slide-in camper occasionally!
One surprise:
The factory (front) dually extensions would not fit over the new hubs and I did not want to machine their insides larger so I ended up replacing them with Arrowcraft hub extensions which fit fine.
It's been totally trouble free since but was little pricey conversion.
Oh well, the plan is to keep this truck.
Since this was resurrected and anyone else stumbling across this doesn't care about the 5 year spread I'll throw in my 2 cents.
I loved my Dynatrac. Besides some creative adjustment to the dust shield for it to not rub it was straight forward.
Everybody's reasoning and history is different so opinions will vary. Yes, it's expensive, but you get what you pay for. I off-road a lot and was going through at least one hub a year. I had a groan in the front end I couldn't find and was casually troubleshooting. The groan was the inner needle bearing and I didn't figure that out until after it grenaded damaging my right front. The parts cost alone was over $1000 to replace all the damaged components so I just ponied up some extra cash for the Dynatrac and never looked back.
I don't plow or go through bearings regularly so I'd rather save the 2k and just grease the stock ones as part of regular maintenance. I can see why a more permanent solution would be preferable though.
10-05-2014, 11:56 AM
