Do I need to pull my transmission?

I have a 67 with a C4 transmission. Since putting my new motor in I've noticed some odd issues with the tranny. Basically, it is spewing ATF when I park it after a drive. The first time it happened I came outside to see a very large puddle of ATF on the driveway. I remembered the car was running hot on the drive, well above the halfway mark on the temperature gauge. I figured it was temperature related but was still perplexed.

The next chance I got I went ahead and changed the transmission fluid and filter since I hadn't in awhile. However I believe I overfilled it by about a quart so I bled out what was about a quart.

The next day I took it for a somewhat lengthy drive. I had no issues during the drive but when I got home and parked it I noticed a very aggressive internal fluid flow sound. A second later I had ATF pouring out everywhere. I tried to stick my head underneath to see where it was coming from but I couldn't make anything out. I popped the hood and noticed that the transmission dipstick had "popped out" of the dipstick tube. For a second I thought maybe this was the cause but there definitely seemed to be a source on the drivers side.

Next day I again changed the fluid and made sure I had the right amount of ATF. On the next lengthy drive I didn't have any problems but when I got home the same symptoms showed up, only less severe. I didn't hear any fluid flowing and the transmission wasn't spewing everywhere. There was also less fluid on the ground. The only place it was leaking seemed to be on the drivers side near the header collector. I popped the hood again and noticed the dip stick popped up again.

What does this sound like? A blown or weak seal? Seems like it was a seal I would have problems with it while I'm driving.

Oh one other thing I noticed. On the last drive as I was heading home I noticed a fairly strong smell of sulfur. Not really sure what this was, smoking ATF? If it was ATF then it appears it is leaking while driving.

Thanks

My C4 is from a 70+ Mustang so this would have the loose fitting cap like vent then? In order to access it, do I deep the drop the tranny?

Thanks.

brianj5600 said:

What kind of cooler are you using? Do you have access to a infrared thermometer? Is one cooler line hotter than the other? It seems like an overheating problem to me. The pump controls flow to the cooler. There is a checkball to regulate it.

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Well I have the auto transmission radiator so just the stock radiator then. I don't own an infrared thermometer but I may be able to get one.

brianj5600 said:

The vent is on top of the tail extension close to the main case. It would be tough to check it for flow, but you could verify the cap is not stuck down. Do you know where the fluid is coming out?

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I wish I knew where it was coming from. The last time it happened it was definitely leaking on the drivers side towards the tail of the transmission. However, I didn't want to shove my head under and have hot transmission fluid pour on my face.

Also, when I was putting the engine back in the car I filled up the torque converter with ATF. However, I'm not 100% that I used type F. Could this have something to do with it?

Felt around up top and felt the vent cap and it wasn't stuck. I also drained the pan and took off the filter again today. I noticed that the fluid was a deep red and that there was a sort of "mud" on the bottom of the pan. This mud has been present the last few times I've dropped the pan. From what I understand this is indicating that the components of the trans are wearing quickly. So, from conversing with you guys and a few others I've come to the conclusion that the fluid is overheating because I have a higher torque engine than stock and the fluid is expanding and draining out of the vent cap. I'm going to go and replace the filter and gasket again and fill it up with 4 quarts of DEXTRON II (It was rebuilt 6-7 years ago.) I'm also going to pick up an external trans cooler and mount it in front of the radiator and see if it helps.

Now, I'm planning in the next 3-4 months to convert the car to a 5 speed. Right now I just want the transmission to last that duration. How much life do you think it has left in it considering the wear I'm seeing? Since putting the new engine in, I have MAYBE 50 miles max on the car/tranny.

So, what do you think of the plan? Sound sane?