Rear differential-cause of failing ? | Ford Explorer Forums - Serious Explorations

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Rear differential-cause of failing ?


Well-Known Member
March 20, 2012
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City, State
Year, Model & Trim Level
'03 Sport Trac XLT (RWD)
Just dropped off my ST at the trans place that rebuilt the rear diff last December. I am 500miles over their warranty but under their 12 month warranty. Paper did not say 12k "OR" 12mo whichever comes first. Just scribbled 12mo 12k on the receipt. I know they can use that anyway against me if they choose.
Anyway, the question is...Since they did not install the drive shaft properly when they did the rebuild. Can I use that as a probable cause to the spider gears having chips in their teeth? Installation error. The Ford factory orange/yellow paint mark on the end of the drive shaft and the paint mark on the diff flange are on opposite sides now after they reattached it. I have always read that you must be sure to align those marks to be balanced correctly. I figure if they are not, that this can cause a slight(but not felt)vibration causing the rear end to fail after 9 months. Sound plausible?
As nice and calm a person I am. I'm expecting the worst from them. They were very defensive on the phone on Friday when I described the issue. Saying that most places wont honor the warranty if you remove the cover. I HAD to, to get the large chips out of it to be able to drive it to them. I experienced a intermittent loud rattle(loose gears). I also get a quick clunk when accelerating. I had to get all the chips out of there. He said I(as in me, Mark) could have contaminated it. Sure buddy, I should've just ignored the broken off large chips and run off the road when it completely failed.
If they do not fully warranty. I'm going to Ford for repair. They(trans place) will not get 1 cent from me. (I spent $3600 at their shop in 2012. Other repair was a Honda trans rebuild. They even botched that when the way overfilled it)
I know there are more factors that can cause this damage. But this one seems to be the most obvious and provable.

Everything is working fine now. Long story. Anyway, the more I think about it- lining the drive shaft up against the diff flange they way the factory did shouldn't matter. The drive shaft is balanced separately off the diff flange. I don't think it matters. As long as you have the u-joints the way there were.