I am going to purchase a 2003 dodge truck with the 9.25 antispin rear end next week. I have been told countless times about these units failing on a regular basis. So i go to the local shop that does nothing but fix differntals all day long and the tech tells me that there is no way to do anything to prevent the units from failng. He said just wait till it goes bad and then put in a new anti spin unit. That is it.

He told me most fail at around 80,000 miles give or take. I have no reason to not beleive him, but is there really no way to prevent them for going bad as you know it will happen on a long trip far from home on a dark and stormy night and in a place so remote............

I have pondered this a lot.

How does one know that the current production 'crush sleeve' does not continue to shorten over time and reduce the pre-load on the pinion bearings?
{best answer so far.... check the torque on the big nut every so many thousand miles}

Which manufacturer of pinion bearings makes the most durable bearing?
{my guess Timken}

Which manufacturer of seals makes the most durable and longest lasting product?

What is the ultimate best way to secure the big nut, once the correct pre-load torque is set?
Locktite?
Aircraft safety wire?
Set screw?
Special bolt design?
Spot weld that could be easily ground off?
{best answer so far: use safety wire and drill big nut on jib}

Is the range of pre-load torque recommended by Chrysler not optimum?
What kind of tests did Chrysler do to determine the range and when were these tests done?
Should you be at the high end of the range?
{best answer so far... too much torque will cause the pinion bearings to fail early, too little torque will cause the seal to fail early}

Is a Torsen style differential,
or an electric locker
a better and more durable anti-spin?

Is any anti-spin design without the troublesome clips that have broken so often in the past a better way to go?

There is also the slightly different question:
is there another differential with less gear friction that would give slightly better MPG?
{best answer so far: maybe the Toyota differential is a more modern design}

Corrct, there is no way to prevent it. But I have never seen one fail where the vehicle still wasn't drivable and I work in a Dodge dealership. Most times the people find out it broke when they remove the diff cover to change the fluid and find pieces inside, usually by then the clip has already cut into the diff housing and bearing cap. I've seen diffs with the bearing cap cut almost down to the bolt hole and the truck still was being driven on the road. If you're that worried about it then I'd just put new clips in after you buy it for that extra piece of mind. The clips are cheap, under 20.00 I think, or install new clutches and clips. The later anti-spins, which is what the '03 has, were better then the earlier ones. IMO

Mine went bad at 99K, a component part inside the Dana supplied trac loc broke and sent all kinds of metal everywhere.
I was able to get it home..slowly..
I believe the problem was resolved by 03 models, and the other issue that I heard of is the front bearing going bad..
Probably change the gear lube and call it a day..
there are issues with just about any manufacturers products..Like Fords spitting out spark plugs..etc..

Must not be a problem on all 9.25, I've had my 88 Ramcharger since new. Got over a 150k still going. But if the anti-spin spits out the clips on my 02 Ram I plan on a Tru-track or Detroit locker, and a soild spacer instead of the crush sleave.

Here is a pic of the heat treated Belleville washer that was inside the Trac Loc until one day it all went very bad....