While I don't suggest ingesting any type of transmission fluid, it's not particularly deadly, so I think you're safe there. =)

You should be able to use just the gasket, with no sealer, if both surfaces are nice, clean, and flat.

One strong word of caution though: DO NOT overtorque the new pan! If you overtighten, it'll dimple the pan as you've seen - and then the space between your new dimples will not have enough pressure to seal properly. After that, no matter how tight you torque it down, the pan will drip.
Additionally, the o-ring for your dipstick tube will frequently leak and run down the case, making it look like the pan gasket's leaking (when it actually isn't.) The o-ring for the shift select lever is another common drip source, and while you've got the pan off, it'd be a good idea to check it too.

There's a really good thread here to check out about that one; it's a little more complicated to fix properly sometimes.

Best wishes, and many drip-free parking spots to you!

 

New issue. When I removed the filter, a spring and pin dropped out. I was not expecting this.

My filter has a tab that holds the spring in the case. My new filter does not have this tab.

I suspect this is not the original transmission to my 65, or at least not the original valve body. My C4 is a case fill.

There isn't a tag on the transmission, the valve body is RF-D2AP-7A101-AA, so a 72-valve body in a who knows what year transmission. A servo.

Any idea how to ID the transmission?

I am going to buy the correct filter. I'm guessing the small end of the pin fits in the end of the spring and the spring goes in the hole with the pin on top.

How I enjoy buying parts that I already bought because the PO made a change. At least I have the 1-2-D shift pattern.

 

That's the throttle pressure limit valve, the spring holds the valve up in place in the valve body.

The valve was initially used in 1970, and the cases are different than the 69-earlier, so you have at least a 70-up transmission. If the tag is missing, look for the casting number and date on the driver's side behind the shift lever.

 

Thanks Hemi. Good info.

My case needs the gasket with the cutouts.

The only gasket I have with the cutouts is a AZ brand rubber gasket.

I'm not thrilled with using that gasket, but can not find a cork gasket with the cutouts.

If I take a cork gasket and make the cutouts, will it seal?

The gasket I removed was cork with the cutouts and after 10+ year it still was not leaking.

 

If you use the AZ gasket as a template to make the cutouts, you should be good to go, just make sure it still covers all the necessary areas. Not a fan of the rubber trans pan gaskets either, prefer cork or the FarPak black composite. Cork I glue to the pan with gasket shellac and let it dry for a bit.

 

I want to do this once and have no leaks.

Here is the cork gasket I removed. Both sides were coated with a gray sealant of some kind. No leaks after 10 years.

I bought a new pan from Summit, the old pan is in excellent condition, but I wanted the drain plug. I'm using the old bolts, the allen bolts the pan came with have less clamping area.

I am thinking about a thin coat of Permatex Ultra Black on both sides of the gasket.

Permatex says "oil resistant". Is there anything better to use?

 

i like rubber gaskets for that. but you dont need any sealant. trick is to evenly tighten it crisscross pattern until it dont leak
dont crank down on it or youll tear the gasket
8-10 ft lbs is plenty

 

Permatex makes a specific RTV for use with ATF.

Amazon.com: Permatex 81180 Automatic Transmission RTV Sealant, 3 oz. Tube , Gray : Automotive

Buy Permatex 81180 Automatic Transmission RTV Sealant, 3 oz. Tube , Gray: Gasket - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

I have made another plan. More later.

I laid both the new and old pan upside down on my office desk and started trying to work a sheet of paper under the lip.

I finally went out and got my feeler gauges.

Neither pan is flat, not even close.

That is most likely the source of many leaks.

 

That is most likely the source of many leaks.

Hummm, if you had that many leaks, my guess is the fluid you just drained is not 10 years old. Certainly you had to keep adding some over the years.

Mine leaks enough that I have never "changed" the fluid.

 

New plan. Install the aftermarket C4 pan with a cork gasket, no sealer and this pan reinforcement from Bronco Graveyard.

I had to do a bit of surgery to make it fit flat, it didn't have the corner cutout and the other cutouts needed a bit of love to fit the aftermarket pan.

I am hoping that the additional clamping force seals up with no leaks.

 

I just replaced my pan/gasket, selector o-rings, and dipstick o-ring. That was weeks ago. I still haven't put fluid back in. Waiting for nicer weather so I can back it out of the shop.

Edit:. I'm trying a Lube Locker gasket.

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Mine is going on tomorrow AM.

I was conflicted about not using a sealant, but Ford didn't use one either.

 

When I got my filter from AutoZone it did not have the tab to hold the spring in so I binned it and just cleaned the old filter out with gasoline and put her back on. Being as it's just a metal mesh filter it shouldn't be a big deal and the fluid change is what I was really going for anyways.

 

FWIW, I use High Tack on my valve cover gaskets with good success. Might be a good candidate for this (cork) gasket too.

@Bdubbs - that’s a good looking pan!

Permatex® High Tack® Gasket Sealant, 4 OZ - Permatex®

www.permatex.com

 

I would have a pan like that if I wasn't so cheap.

 

I made a dash to Summit today. Not really a dash, between Florida traffic and Atlanta creeping south, it's more like a brisk walk now.

Summit had a lubelocker pan gasket in stock.

Summits website isn't very user friendly. It takes some work to find parts they have in stock. In this case I had to search for "lubelocker gasket". Searching for C4 transmission pan gasket" did not return the Felpro or lubelocker results.

New filter, gasket, pan and pan reinforcement is on, torqued to 18 ft lbs, check valve is on, C4 kickdown is on.

No fluid until I put the new radiator in and hook the cooling lines back up.

Based on my visual inspection, it looks to me like my fluid leak is coming out the vent tube. I have a dipstick o-ring on the way and the shifter shaft is clean, so hopefully no more fluid on the garage floor.

 

I made a dash to Summit today. Not really a dash, between Florida traffic and Atlanta creeping south, it's more like a brisk walk now.

Summit had a lubelocker pan gasket in stock.

Summits website isn't very user friendly. It takes some work to find parts they have in stock. In this case I had to search for "lubelocker gasket". Searching for C4 transmission pan gasket" did not return the Felpro or lubelocker results.

New filter, gasket, pan and pan reinforcement is on, torqued to 18 ft lbs, check valve is on, C4 kickdown is on.

No fluid until I put the new radiator in and hook the cooling lines back up.

Based on my visual inspection, it looks to me like my fluid leak is coming out the vent tube. I have a dipstick o-ring on the way and the shifter shaft is clean, so hopefully no more fluid on the garage floor.

View attachment 839384

Awesome work!

My dipstick o-ring area looked dry, but replaced it anyway. I put a little right stuff rtv on the o ring.

Hopefully in a week or two I'll be pouring fluid and crossing my fingers.

Mine has been in winter hibernation, so it hasn't run since November.

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Thanks for the pic, I found the gasket because of it.

Hopefully I am adding fluid tomorrow, running through a heat cycle, retorque and good for 5 years of trouble free miles.

 

Did you end up getting yours running? Initially I thought I had mine leak free...

No leaks during initial start up and filling up the transmission. Re torque the bolts after first heat cycle. Started it up days later and pan was leaking. Some bolts were loose so I tightened again.

3rd time started it up, ran it for awhile, bolts still snug, but now I still have a pan leak towards the back bolts after it sits for a couple days....

Frustrating to say the least.

Edit:

Mine actually looks like it's quite possibly the front pump seal. And it's running along the top of the transmission pan.

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Haven't fired her up yet.

Decided to install the Borgeson PS kit that has been in the trunk two years and the Ididit tilt column I bought.

Getting closer.

 

I know it’s been a few years since this thread was talked in but I did have a question about replacing the gasket and filter. I have a 74 C4 in a 65 Mustang and i noticed the PO did not torque down the pan bolts and so fluid was leaking out of the pan for quite some time before I got around to it (it sat till I was able to get to it). I went ahead and replaced the gasket since I was already there and noticed about 1.5 qts came out when I removed the pan. I figured “okay well it leaked a decent amount overtime and so it probably didn’t have much left”. I went to go fill after I completed the install and it only took 1 qt before the dipstick tube overflowed with fluid. Am I missing something? Am I supposed to cycle through the gears to allow the fluid to move around? It just seems that with what was lost over time while it sat and with what I lost removing the pan it should be taking more fluid. Prior to the gasket install I also had it running to mess with some timing and when I checked the dipstick at temp it wasn’t even registering on the dipstick. I then shut it down and did the gasket install after it cooled off. I’m just super confused with how little it took. I don’t know if that’s normal or if it needs to be cycled or if there is a potential blockage of some sort

 

C4 pans are pretty shallow and don't hold much. Most of the fluid stays in the torque converter. I'm not clear on your fill procedure. You WERE filling it with the engine running and in Park, right? You can only add so much fluid to an automatic without the engine running before it overflows.

 

That is correct. If you have a plugged vent it will indeed spit back out of the dipstick tube before you get much in there. One solution is to pour it in painfully slowly. Short of clearing the vent. Ford Taurus transmissions were notorious for that, for example.

 

I'd spray it with brake clean (carb cleaner, or whatever was handy) and blow it with some air too.