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700r4 building pressure.

14K views 11 replies 7 participants last post by  stuarta 
#1 ·
I have a 700r4 that is recently rebuilt. It is leaking from the detent cable and transmission dipstick under the hood. When the engine is running with dipstick removed it shoots from the trans dipstick. It is also a slow but constant drip coming from the detent under the hood. Trans fluid is leaking onto my manifold on the drivers side and onto the header on the passenger side. The transmission is not over filled and I am absolutely stumped as to what could cause this problem. Transmission shifts fine, just this stupid leak I cant figure out.
 

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#5 ·
Recently rebuilt so assume the vent was cleaned or new. I had this same problem when I rebuilt my th350(my first rebuild). Leakeked out same places. What I found out was even though I was reading "FULL" on the dipstick, there was too much fluid in the teranny' I now run it with less fluid but still reading on the DS. I got a tranny cover with a drain plug and can let some out if I overfill. I keep a cplose eye on it and carry a quart of tranny fluid with me .:welcome::welcome:
 
#7 ·
The sealing rings on the input shaft could be leaking pressure causing leaks and fluid to come out of the vent. If no fluid is coming out of the vent and the vent is clear then lower your fluid level down to the "add" mark and run it like that and see if the leaks go away. Like someone else said your dipstick maybe not be accurate and you may have too much fluid in it.
 
#8 ·
The pressure feed and the vent are adjacent to each other inside the front pump. A common problem as these transmissions age especially if they've been overheated is the pump housing warps opening a bleed from the pressure passage into the vent passage. If this happens it blows pressure oil out the vent tube.


Bogie
 
#11 ·
hey guys thank you for all the responses. I found the vent connected a fuel line and tried to blow through it. At first no air passed but after a few sucks I was able to pass a coffee straw sized amount of air through the hose. I will refill my fluids and see if it happens again.
 
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