Has anybody ever had diff fluid come out of the vent on the diff? We were practicing for an upcoming event and my buddy was driving the car in a pretty hot session and when he came in, we found that some of the diff fluid had come out of the vent tube. Summit Point's main circuit is 2 miles long and on the front straight he was getting a bit over 150 MPH. Needless to say, everything was pretty hot. Also, I am running a Kaaz LSD with Kaaz fluid - not sure if the Kaaz fluid has any different properties.

What is the likely cause of this? Is it getting too hot? Is it from some of the really hard turns (he lifts the inside rear wheel in 3 of the 10 turns). The fluid level was right on before he went out, so it wasn't because it was overfull.

Any input would be greatly appreciated.

-YS

PS Krazik - thanks for the advice on the 275/45 Hoosiers - we picked up almost 2.5 seconds over the old tires.

 

There's a vent on the diff?!

 

Yup, it's #13 in this diagram:



-YS

 

Hmm.. never ever had it leak fluid. Maybe yours is bad?

 

[QUOTE]Originally posted by krazik
[B]Hmm.. never ever had it leak fluid.

 

could be. I don't have any experience w/ the Kaaz. I know the Reverend mentioned it gets really hot. Silver Surfer has one in his car, but he drives his car rather leisurely

 

That hasn't happened to mine before... You sure it wasn't overfilled? It's only supposed to be filled to the bottom of where the fill plug goes...

The Kaaz units do get VERY hot though, so maybe you worked up some froth or something in there - I dunno.

I wish I could afford to put a diff cooler on my car - it would save me money on diff fluid in the long run.

 

[QUOTE]Originally posted by The Reverend
[B]That hasn't happened to mine before...

 

if you didn't overfill it, then you boiled over the fluid which is not an easy task. Is your diff unit still noisy or is it fully broken in? If still noisy, add some friction modifier.

I'm going to be running a temp probe in the diff unit at my next track event to monitor my diff temps, if it gets hot, a cooler will be needed. My underpaneling restricts all airflow to the diff.

 

Here's another thought - I've read reports of leaking differential mounts, but I've never heard of a leaking diff before. If the mount is above the tube, fluid from it could have dribbled down causing some confusion as to its origin. Carefully inspect the fluid-filled diff mounts before going to all ofthe trouble of servicing the differential unit itself.