Are you checking the transmission fluid level with the engine up to operating temperature, idling, and on level ground? When the transmission warms up, the expansion of the air inside the transmission can force the the trapped fluid out of the vent, leading to the leak. Leaks Out of the Dipstick Some 2009 Escape and Mariner vehicles equipped with 6F35 automatic transmissions and built on or before 10/29/2008 may exhibit a loss of transmission fluid from the dipstick tube area. Wow. According to the temp gauge, they're not overheating when this happens and the engine isn't getting hot either. That is not high enough to leak out the vent, but plenty high for the fill tube and servo to … This is not a leak around the trans filler tube, as the fluid actually comes out from the top. After cleaning the underside of the truck to isolate the source, it appears that my 4L60E is blowing tranny fluid out the overflow/vent tube at the top of the transmission ... which is then all sorts of fun to find because it hits the spinning shaft and is, thus, spun/slung radially along the underside of the … After cleaning the underside of the truck to isolate the source, it appears that my 4L60E is blowing tranny fluid out the overflow/vent tube at the top of the transmission ... which is then all sorts of fun to find because it hits the spinning shaft and is, thus, spun/slung radially along the underside of the … LEE. This is not a leak around the trans filler tube, as the fluid actually comes out from the top. I drained the pan prior to pulling the engine/trans as a unit. However it could also simply be a crappy design. RV runs great. The most likely cause is the vent hose might be clogged. Under load blowing atf from breather vent HT740 in MCI MC7 bus - Answered by a verified Technician We use cookies to give you the best possible experience on our website. Trying to fix this thing. Low enough that the intake port or pick-up tube in a reservoir is able to draw in air. It has to be able to breathe. Check the fluid level after the car has been sitting and before starting the engine to see how high the level is after sitting. Transmission fluid can leak out these vents if it is too high. In this case, you would need to clean out the vent carefully. However, in the warmer months the transmission is quite happy running in the 200-230 range. I’m sorry this has nothing to do with this but I’m running out of ideas I have an s10 with a 355 and 350 turbo when I put fluid in the trans it fills the tube up pretty fast but it’s low like low enough to have a hard reverse shift and feel it slipping in drive I can jack the truck up on the dipstick side and it goes in easier but in both cases it will leak out from between the tube and trans and sometimes when driving you can stop and it will leak in the tube and trans do not understand it any help is much appreciated, Powered by Discourse, best viewed with JavaScript enabled. What would cause transmission fluid to pour out from the filler tube. I bet you see the level will be approx an inch or 2 above the full mark. Replace filters and fill with the OE spec'ed fluid. However, you could still lose this fluid if a leak were to occur somewhere in the transmission system. Contact a shop to remove the transmission and replace the cooler. This is another reason I run the lubes I do I can tell the oil from transmission lube and primary ... OK, put it up on a lift yesterday. I would top it off n level it n ride it again and it would do it again. Ever since I switched to AMSOIL fluid, I haven't had an issue at all. A new transmission dipstick and filler tube kit is now available You can normally wait until you drive 100,000 miles before you need to change your automatic transmission fluid. Fluid seepage out of the vent tube can sometimes be normal, but can also be caused by overfilling. Perhaps someone in an old car club might know the answer. Fluid + Filter Calculator. Transmission is leaking oil out the vent on top of tranmission. All rights reserved. This can cause aeration of the oil and as that bubbly or foamy oil rushes back to the tank, it can be more than the tank volume and can come out of the vent cap. I don't know your transmission but most domestics have a vent tube/hose. Any advice or encouragement? This can cause aeration of the oil and as that bubbly or foamy oil rushes back to the tank, it can be more than the tank volume and can come out of the vent cap. I set the fluid level at 170°F and in the middle of the crosshatch's. If not, that’s how it should be done. This publication is revised periodically to include improvements, new models, special tools, and procedures. This may be due to transmission being overfilled. If there is that much behind the drive pulley it is probably the trans seal. It has most likely also leaked into the radiator. This redness is the color of the transmission fluid. I checked the fluid with the engine at operating temp in park multiple times. The Allison, from what I know (which usually isn't much ), will run really cold, or really hot. A few weeks ago I swapped out all of my fluids. A 1970 Chevy automatic runs fine, except for trans fluis leaking. Answer (1 of 3): There are a few possible causes of transmission fluid coming out of a dipstick hole. The seals higher in the transmission may also leak, but these seals are not pressurized. Any amount of fluid needs to be vented. 2. Transmission fluid is leaking out of my transmission vent tube. This should give you some good ideas. That's interesting and helpful. If you don't have a vent, then that's exactly what will happen, fluid coming up through the dipstick, since it's the easiest thing to give under the pressure. Discover the Allison Advantage. The most likely cause is the vent hose might be clogged. If the vent isn’t routed through the pump, there are only two possibilities for fluid leaking out the vent: 1. Really? mr josh nailed it. Learn how you can ensure the performance and durability of your Allison transmission. Hmmm. If the vehicle is driven through water (as in a flood) and the water level is at or above the vent, the water will cool the unit lowering the internal temperature and water is drawn inside of the transmission. We hoped for a bad or loose, tranny filter or seal. Can the transmission cooler in the new radiator be bad? The transmission did not make any usual noises. Learn how you can ensure the performance and durability of your Allison transmission. I've never heard that one before. High transmission fluid levels and a failed vacuum modulator may throw fluid out in an Allison transmission. Allison Transmission is the world’s largest manufacturer of fully automatic commercial-duty transmissions, and is a leader in hybrid-propulsion systems. GM has updated dipstick Part #15115171 which has vent slot added in it to vent more pressure out of unit. Answer (1 of 3): There are a few possible causes of transmission fluid coming out of a dipstick hole. No overflowing in park and at standing idle. when i came back out after a few minutes there was a large puddle of transmission fluid under the jeep and it was pouring out of the vent tube and fill tube.