EricCartmann said:This is a question for all you smart guys out there. Why are the rear diff's failing. What is it about the design of the Titan's rear diff that is making it failing?
Originally, the BT/OR trucks came equipped with a 2-spider gear diff, which had the crappy spider gears. Then they upgraded to a 4-spider gear diff, which still had the crappy spider gears. Finally they upgraded the materials that the spiders are made of and it's 'up to par' for 08.
I myself think that it is too little. The Titan makes good power and when I look at all the stuff underneath my truck everything is huge except for the rear diff.... it is puny!
I also am thinking of going to a Detroit Truetrac just so I could avoid my rear diff from failing on me. But will this correct the problem? I don't think it will completely as the Diff will still be the same size.
Yes, it will correct the problem, as it replaces all the parts that have been causing failures, basically making it bulletproof, to an extent. The spider gears are whats failing, not axles or ring/pinion gears. The spider gears explode and send fragments all throughout the rearend. There have been ZERO reported failures on rearends equipped with the TruTrac
I have the BT package and 4x4, and from what I have been reading, rear diff problems happen most often with:
1) lifted trucks
2) when 4x4 offroading
3) if you have BT package
4) when you tow a lot.
5) occurs about the 50k mark.
I'd put them in this order:
1) BT or OR package
^^Yes, that's it, my personal thoughts are that lifting your truck, offroading your truck, towing with your truck, and the number of miles on your truck have very little to do with whether or not it will fail. Most of the reported failures have happened on trucks that have done none of those things. It's simply 'luck of the draw', so to speak, on whether you purchased a truck that has crapp-o spider gears or not.
Originally, the 04 models came with the steel diff cover and non-synthetic lube. This is what was originally believed to be causing the failures. Yes, that was contributing to it, but there was a much bigger problem at hand, the spider gears. Even after Nissan upgraded to the heat-sink aluminum cover and the synthetic lube, failures were still occurring at an alarming rate.
Certainly, the larger, heavier wheels/tires that go along with lifting a truck could have a small affect on things, but if you've got a POS rear, it's gonna fail sooner or later, regardless of what wheels/tires are on it. Keep in mind that adding a lift doesn't have any effect on the rear diff. (except maybe pinion angle), it's the wheels and tires that would cause a problem.
Towing with these trucks, I hear is amazing, and there are hundreds of owners out there who have towed countless miles with no problems. If you've got the crapp-o spiders though, it's gonna fail sooner or later though.
People break stuff offroading all the time. Sure, if you offroad your Titan, your chance of failure might slightly increase because of increased stress on those nasty spider gears, but once again, if you've got crapp-o spiders, it's gonna fail sooner or later, whether you offroad or not.
If it hasn't failed by 50k, I would feel somewhat confident that you have a 'good' rearend. Who knows for sure though? Some have had them replaced once, and then the replacement fail within 3000 miles???
My remarks in BOLD above.