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Another odd c4 issue

phred

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Aug 25, 2006
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This is the same c4 I was having nss issues with.
Tranny is completely rebuilt. Stage in b&m shift kit. It shifts solid and pulls hard. The problem is it spews fluid at highway speeds. Cruising around town under 50 mph and it’s fine. Above 60 and it sprays it out. It’s not coming out of the vents, servo covers or any other obvious place. Best I can tell is the drivers side rear corner of the pan. There’s no high pressure ports down there. Why doesn’t it leak just sitting or at low speed. I’m gonna pull the pan and check the valve body but beyoud that I can think of what else to look for.


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Rustytruck

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Feb 24, 2002
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10,872
At speeds when cold it will spew fluid out the vent. When cold and running the fluid will be low on the tip of the dipstick. Hot will bring it up to the full mark. If cold and full it will spew the excess.
 

pcf_mark

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Jun 11, 2010
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3,696
What Rusty Truck said. Just a speck on the dipstick cold is enough. Also if it is over full then you can foam the fluid which is not good for anything.

Check that the vent on the top of the trans is connected to a long hose that goes up to the like the top of the dip stick or something high.
 

Skiddy

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Oct 8, 2003
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11,587
mine was doing something similar, finally found a pin hole in one of the lines
 
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phred

phred

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Not from the vent or lines. The case is completely dry. The only place I can see fluid is the drivers side corner of the pan. Fluid now is at the add line on the drip stick when it’s hot.


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B RON CO

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Hi, make sure the pan is flat, and none of the bolt holes are puckered up. I always liked the rubber gaskets. Best to glue the gasket to the pan and bolt it up after the glue has time to dry. Just snug the bolts up. Small 1/4 drive ratchet, evenly around the pan, with a gentle twist on the last time around. Good luck
 
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phred

phred

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T-case is dry too. Pan is a cast alum b&m pan. It was on the tranny before the rebuild. It never leaked before. What’s so weird is it only leaks when you are at hiway speeds. No drips just sitting or cursing around. Hopefully I’ll get home from work early enough tonight to pull the pan.


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pcf_mark

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Jun 11, 2010
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Wow that sounds maddening! Good luck and let us know what you find. Any chance it is leaking from the front seal and following the pan edge then dripping?
 

KBUCK1

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Joined
Feb 8, 2011
Messages
979
Mine done the same thing. It was puking out of the vent at high rpms. The vent is on the adapter housing i believe. I could never find fluid on the case either. Just rear corner of the pan. Pull your tcase shifter boot off and inspect from the top side. I put a catch can with vent on my b&m pan. Solved the problem
 
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phred

phred

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Mine done the same thing. It was puking out of the vent at high rpms. The vent is on the adapter housing i believe. I could never find fluid on the case either. Just rear corner of the pan. Pull your tcase shifter boot off and inspect from the top side. I put a catch can with vent on my b&m pan. Solved the problem



How did you plumb the catch can? Got any pictures??


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EBGeek

Sr. Member
Joined
Nov 25, 2008
Messages
411
Any chance its coming from the modulator mounted on the rear passenger side of the trans? That would possibly explain it only being on the pan seal level, as its right above the top edge of the pan.

I recently had a maddening leak and dropped my pan, did a meticulous reseal only to find it still leaking. It ended up being a 99 cent O-ring on the modulator...just a thought.
 
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KBUCK1

Sr. Member
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Feb 8, 2011
Messages
979
How did you plumb the catch can? Got any pictures??


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I took the vent out and tapped the hole to accept the braided line that came with the catch can. Believe i got mine from jegs
 
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