My st400 auto trans is pushing fluid out the dip stick tube. Not a grat deal, but enough to leave a bit on the floor when parked. This is a new phenenomon as I have been driving this for 4 years since rebuilt. It has a B&M kit in it. I have checked the fluid level and also made sure the breather tube is not plugged. Any help would be greatly appreciated
Check the breather tube real close Mud Daubers like to build nest on them, and run a piece of wire thru it to be sure it’s not clogged. You may have to change the grommet on the filler tube.
As @squirrel stated, blowing out the top or leaking at the bottom? If out the top, vent is plugged. If out the bottom, does it have the single O-ring seal, or the newer cup style seal? How are you cooling it?
Thanks for the reply. I blew on the vent tube and because of fluid level, the fluid game out the top of the filler tube. I forgot about the torque converter letting fluid bleed back into the trans. I also wrapped a strip of towel at the top of the filler tube, went for a drive, the towel had fluid on it. ever where else is sealed good and do other traces of fluid.
If it is coming out of the top of the filler tube, I would suspect either it is over full or it is overheating.
Where'd ya get the dipstick? On a similar note, is the fill tube shortened? Nobody likes a lyin' dipstick...
OK, since you have been driving it for 4 years and this is new, what changed? Add any fluid? As I asked earlier, how is it being cooled? Through the radiator? Typically, when the fluid cooler fails internally in the radiator, you see transmission fluid in the coolant. Does the fluid look burnt? Shifting still firm? If a clutch pack is slipping, heat will build up and expand the fluid, but usually out the vent.
To get fluid to come out of the top of the filler tube the vent would have to be plugged, as it's lower than the top of the fill tube. It should come out of the vent first. Also to push fluid out the top of the fill tube, the vent would have to be plugged or the case would not build up pressure.
Thanks for the reply. 10 years ago when I built the car I shortened the fill tube and the dip stick by the same amount. It has been OK for all this time.
Thanks for the reply. Nothing has changed, I have an external cooler ( Deral) mounted under the frame rails. My temperature gauge on the ****** runs at 150 deF. The shift is solid. The vent is clear. O built the car some 10 years ago and everything has been OK up intill now.
What type of filter does the trans have? Is it an early 400 with the side winder filter or the later style flat type that lays in the bottom of the pan? Reason I ask is the later type with a Dacron element has a tendency to become restricted over time. If that happens, there is a possibility that the fluid returning to the pan can't be picked up fast enough and the fluid level will rise to the rotating parts and fluid will be pushed up the fuller tube, just like if it were overfilled. Bill
Thans for the reply. The ****** is a 66 switch pitch. It has deep pan (Extrafluid) and a flat filter ( br*** screen type) mounted at the bottom of the aluminum pan.
Is the torque converter shifting from low to high stall as it should? IIRC there is a plug in one of the pump ports (looks like the end of a fuse) with an orifice drilled into it of about .100". If that orifice plugs, the converter may not be filling properly resulting in a high fluid level.
The tube the filter is attached to, did you double up the o rings where it fits into the case? I always put two o rings there to prevent aeration.
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