Originally Posted by Dadicool59
Thanks for the responses guys but still no answer to WHY? we should have to change the FD oil. As previously questioned, gearbox or differential oil should not degrade or oxidise like engine oil does.
Grifscoots, what the hell does crunch up the oil mean?
I have had cars that I have done 70-80000 miles in and never had to touch the gearbox or diff oil.
A couple of you have said that post 600 mile oil drops are coming out clean, does this not then suggest that it is unnesesary.
Can't speak for Griff, but I'm pretty sure that he meant that the new metal, gears, bearings, shims, whatever else, inside the final drive, machine themselves down a bit. Little pieces of metal turnings, shavings, chunks, that are formed as the new parts settle into each other.
You'll want to get those contaminants out of there. Especially with some evidence of final drive failures out there with this design.
Just did my 700 mile service on my '08 GT. The final drive fluid that I drained out was DEFINATELY DIRTY. Which is to say, contained lots of fine particles. Looked GRAPHITEY for lack of a better word. The heavy particles at the bottom were the last to drain from my collection pan into my recycling jug. That stuff was quite thick. Should have put a magnet in the sludge, but it didn't dawn on me to do so at the time.
Good point about the car tranny and differentials though.
In, what seems like another life, I worked at an auto junkyard. Hmmm. Automotive dismantling and recycling center. Anyway. Very few folks back then ever changed their differential or tranny lube as a maintenance item. The stuff that came out looked like tar. And the differentials and manual trannys almost never broke.