Author Topic: Transmission Fluid Out Dipstick  (Read 4549 times)

Offline Mule man

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Transmission Fluid Out Dipstick
« on: February 14, 2010, 06:47:10 PM »
Just bought an '84 Chevrolet 4X4 with a TH350 tranny.  Runs and shifts great but now it's started blowing tranny fluid out the dipstick.  I did a search and it seems everybody thinks it's the vent tube.  I blew the breather out (and blew tranny fluid everywhere) and put a dipstick with a good rubber seal on it but it's still blowing fluid out.  It is about 1 qt low so no overfill problem.  I  just took my air compressor and blew air into the dipstick and out the vent so I am sure it is open. I need any advice that can be given.  Thanks in advance.

Online VileZambonie

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Re: Transmission Fluid Out Dipstick
« Reply #1 on: February 14, 2010, 08:13:14 PM »
What's the history on the trans? There shouldn't be pressure in the case if the vent is clear.You're checking the fluid level on a level surface with the engine running right?
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1974 GMC

Offline Mule man

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Re: Transmission Fluid Out Dipstick
« Reply #2 on: February 14, 2010, 08:32:41 PM »
Yes, level and and a warm tranny.  It's about 1 quart low now.  I also checked the dipstick with another 350 tranny and they are the same length. The PO said that he had recently changed the fluid and filter.  It has been fine for 100 miles or so.  Shifts fine.  He had installed an aftermarket in the past.  Could that somehow pressure the fluid?  It beats me.  Thanks for the reply.

Offline Mule man

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Re: Transmission Fluid Out Dipstick
« Reply #3 on: February 14, 2010, 09:10:04 PM »
That should have said "aftermarket cooler" sorry. I have had one person tell me that it's the modulator valve.  I don't see how that could pressurize the fluid in the pan.  Thanks again

Offline Mule man

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Re: Transmission Fluid Out Dipstick
« Reply #4 on: February 15, 2010, 11:19:42 AM »
I've also been pointed toward "lip seals".  Could them leaking cause this problem.  Thanks again

Online VileZambonie

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Re: Transmission Fluid Out Dipstick
« Reply #5 on: February 15, 2010, 06:18:16 PM »
Barfing out of the dipstick usually means overheating/overfull/plugged vent.
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

1974 GMC

Offline frito-bandito

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Re: Transmission Fluid Out Dipstick
« Reply #6 on: February 17, 2010, 02:13:09 AM »
My 94 with the 4L60E does the same thing, I've been keeping the fluid about half a quart low to slow this problem for about a year now. I was told that it could have something to do with the torque converter.
1981 Chevy dually 350 4spd. (One piece at a time)
1994 GMC C1500 4.3L 4L60E. (340K Daily Driver/Resto-Mod)
1998 GMC C1500 5.0L 4L60E (179K Daily Driver)

 


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