Rear differential fluid?
#22
Okay I don't have dyno numbers nor did I drain the fluid for the spectrometer so I don't know what kind of analysis youre looking for.
Driving the car here is what I notice from the amsoil 110w compare to the green stuff that came out which I assume is LE.
1) the car is definitely quieter. Whatever gear noises I had (amplified by my hardtop) is now reduced a good 50%. The tranny is silky smooth when cold and totally butter when warm.
2) I don't know if this is a good or bad thing...I don't feel the lsd anymore or maybe I haven't pushed the car hard enough. With the old fluid I felt the lsd was aggressive at locking, when I made turns with my right foot in the gas the car felt like it wanted to snap straight or throw the rear end out. Coming out of turns the car is fighting to go straight. Was a new feeling for me since I've been driving fwd mostly, I have a 911s too but doesn't feel like this. Reminded me a lot of my friends 240sx with a super aggressive clutch lsd without the chatter.
I no longer feel any of this with the new fluid. The lsd feels extremely smooth...maybe too smooth. Feels almost like an open diff now, I haven't pushed the car that hard yet. Maybe the lsd will show itself if I get more aggressive with the car.
Thoughts comments?
Driving the car here is what I notice from the amsoil 110w compare to the green stuff that came out which I assume is LE.
1) the car is definitely quieter. Whatever gear noises I had (amplified by my hardtop) is now reduced a good 50%. The tranny is silky smooth when cold and totally butter when warm.
2) I don't know if this is a good or bad thing...I don't feel the lsd anymore or maybe I haven't pushed the car hard enough. With the old fluid I felt the lsd was aggressive at locking, when I made turns with my right foot in the gas the car felt like it wanted to snap straight or throw the rear end out. Coming out of turns the car is fighting to go straight. Was a new feeling for me since I've been driving fwd mostly, I have a 911s too but doesn't feel like this. Reminded me a lot of my friends 240sx with a super aggressive clutch lsd without the chatter.
I no longer feel any of this with the new fluid. The lsd feels extremely smooth...maybe too smooth. Feels almost like an open diff now, I haven't pushed the car that hard yet. Maybe the lsd will show itself if I get more aggressive with the car.
Thoughts comments?
#23
Registered User
Sounds like the old fluid (LE or Redline) needed to come out of there. I like the description of what you are experiencing now. I predict that you've chosen a good gear oil.
#24
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jh4db536 Posted on Feb 4 2011, 10:10 PM
Signs the diff oil can't deal with the gears inside the Torsen anymore.
I've noticed this (and posted about it) too.
An oil change changed diff behavior, or better said: brings it back to normal.
Torsen also mentioned, in a mail I once send to them with this question:
In a car where one can feel a difference when the tires are not all equal, one can feel "worn" diff oil, IMO.
I wonder how many cars are driving around with oil that makes the car handle differently, not as it should.
Maybe a lot of drivers don't know any better using diff water all the time.
Btw.. it's the final drive gear set that mostly eats up the oil.
That's where all the grinding and munching is going on, every mile you drive.
... aggressive at locking ... turns with my right foot in the gas the car felt like it wanted to snap straight or throw the rear end out. Coming out of turns the car is fighting to go straight.
I've noticed this (and posted about it) too.
An oil change changed diff behavior, or better said: brings it back to normal.
Torsen also mentioned, in a mail I once send to them with this question:
To the average driver the change is not even noticeable but the oil can slightly change handling characteristics of the unit.
I wonder how many cars are driving around with oil that makes the car handle differently, not as it should.
Maybe a lot of drivers don't know any better using diff water all the time.
Btw.. it's the final drive gear set that mostly eats up the oil.
That's where all the grinding and munching is going on, every mile you drive.
#25
I've also noticed more predictable rear end behaviour on long sweeping curves with a thicker diff fluid , going from 75w/90 to 75w/110, and now 75w/140. I like that aspect of it.
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