Postby Hasbeen » 31 Aug 2008 00:24
Paul, I think your diff may have had the same problem that made me
fit the Nissan Skyline diff, [with limited slip] to our 8.
I believe the lubrication of those gears, [the planet gears, or
wheels, depending where you come from], is insufficient, & this
causes the failure. With my son's rather enthusiastic driving style,
we had 4 fail, all the same way. [He does come home from 3 months at
sea, with his hoon instincts built up to a high level]
When just one rear wheel is spinning, ie; comming out of a corner
with too much power on, [or bad drag strip starts] those gears have
to rotate at a reasonably high speed, on their shaft. With no
provision made to get oil in there, other than seepage, the bearing,
& the shaft, rapidly dry of oil, & start to get hot.
In a very short time they are hot enough to weld together. When this
occurs, you have a "welded" diff, of old dirt track fame. There is
no longer any differential movement between the wheels. Neither that
little shaft, or the gear can take the strain, & the gear, or the
shaft, or more often both, break. We have had the off side gear in 5
pieces, with a bit of broken shaft still welded to one bit, when
stripped. [Have you ever noticed that people who drive on the left
of the road, drive harder/sillier out of right hand corners]
Of course, the simple, if expensive answer, for high power 8s is to
fit a limited slip centre to the thing, & then this can't happen.
Failing this, I would make provission to get more oil into that
gear. We did machine a groove on one shaft, & it lasted a little
longer, [not much], but I was probably too conservative with my
groove.
I think an other trip to that den of iniquity, with much money in
your hand, is in order, somewhere in the future.
Hasbeen
PS. People who do "burn outs" with an open diff, have the same
problem. If I find that son has EVER done a burn out, with that car,
guts for garters, would have nothing no his fate.
