Originally Posted by cams290
After the long drive from Port Arlington to Heathcote and back to Melbourne, and the FPV drive day i have noticed my diff is whining again !
It was in for its 15,000k service today and the service advisor took it for a spin and confirmed my suspicions.
The original diff whined from day one, this replacement has done about 7,000 k's and has only started to whine in the last week or so.
Why in this day and age with all the technology we have, they cant manufacture quality components ?
I have a pretty good ear for mechanical problems as i am a qualified mechanic, but been out of the game for over 12 years.
How many unsuspecting people are driving their vehicles around with noisey diffs etc... and dont realise it ?
A new diff is on order and will be tested and delivered after christmas, the other replacement took over 5 months to arrive !
All i expect is to have a car that can cruise along at 100k's with out a noise like a mosquito in my ear. Dana must get their act together, they obviously cant build diffs with the correct tolerances, how hard can it be ?
Firstly, congrats on your debut 14.14. Great debut pass in an auto pursuit.
The problem with the diffs is at Dana's end, and in my opinion is a pinion pre-load issue.
People who have tried to do their own diffs over the years have noted that its not as simple as bolting in a set of gears. The pinion depth must be set correctly to ensure a proper acel-decal operating pattern for quietness and long crownwheel and pinion life.
When the pinion is installed, I have noted that the acel/decel pattern Dana adhere to seems to be within spec, however the pinion does not have enough pre-load. The result is a quiet diff until the pinion bearing wears in, and becomes slack, allowing the pinion to move around more freely.
THIS IS THE NOISE YOU ARE COMPLAINING ABOUT.
The fix is to re-set the pinion, but to a higher (closer to crownwheel) location, pre load it to a higher tension. A secondary problem is created here, but we can achieve the right backlash with careful shim selection, providing a more stable envirionment.
Any BA Dana diff we have inspected has had "loose" pinion pre-load. Its a simple fix, and relatively inexpensive one (unless he is driving a phantom ute, no discounts for him lol)
My personal car has travelled 8500 klms, and is on its 3rd diff. I have just informed my dealer that I will be doing this one myself. (maybe a ratio change). In my opinion, the "production line" style of building these diffs is the problem, with each set of bearings and gears slightly different in manufacture tolerance, so they each need their own amount of attention in setting up, some more than others
Anyone who needs help in this area, we will only be too glad to help. The price of genuine 4.11 and 3.7 gears has fallen dramatically, so PM me if you need help in this area. If you call in, just mention your forums name for a tea/coffee and the cheapest and best diff in melbourne, over 30 years experience.
on behalf of Northern Differentials.