C-6 Transmission Leak

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73Mach1Mustang

Well-known member
Joined
Jul 8, 2012
Messages
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Location
Northeast Pennsylvania
My Car
1973 Mach 1
Gentlemen,

I have a leak on my 1973 Mach 1 with a C-6 Automatic Transmission and a 351 Cleveland. I know I need a new gasket and filter, but I think I may have a somewhat unusual transmission pan in that it is fluted (please see the attached picture). I did a few searches and have not found anything similar in regards to a C-6, does anyone know anything about this transmission pan. I guess my primary question is should I order a standard gasket and filter or do I need a special one (I am positive that it is a C-6 based on the shape of the transmission pan)? Also since I am going to have the fluid changed and the filter replaced should I consider a deep transmission pan? As always your recommendations are appreciated?

Sincerely,

Dave

Transmission Pan.jpg

 
I am guessing he is referring to the holes drilled in the front of the pan. I have seen finned pans but never a pan with holes in it don't see the advantage.

 
You have to go back quite a few years to find those. The holes were supposed to allow air to flow through the tubes, cooling the fluid. Did they work? Probably not, or they would still be around.

It will use a standard pan gasket.

 
Yes, it is a "standard" pan. I had a similar one when I was running the 351C and C6 in "Fire" (my 1973 Mach 1).

It may or may not have worked but I never had any issue relative to cooling:).

BT

 
Hi Marks, MWeeps,

By Fluted I mean that those holes seem to be pipes that go from the from to the rear of the transmission pan. I guess the idea is like the finned approach of creating a greater surface area for cooling/air flow. Of course I don't know that it makes any difference with the exhausts being right next to the transmission pan. I am currently looking at JEGs gasket and filter kit http://www.jegs.com/i/JEGS+Performance+Products/555/60905/10002/-1 and TCI racings http://www.jegs.com/i/TCI/890/428500/10002/-1 any thoughts, anyone?

 
The tubes in those pans usually plugged up with mud and other road debris, and the network of tubes on the inside made the pans all but impossible to clean properly. I remember these pans from many, many years ago; they were a bad idea then, and still a bad idea, today. Unless you are doing some off roading, stick with a stock pan and make sure your transmission cooler lines and heat exchanger are clean and flowing well. If you switch to an aftermarket high stall, then add an auxilliary cooler to your system. Cooling devices are most effective when handling the fluid at its hottest and that is when it is exiting from the convertor. That is why factory cooling systems pipe the fluid from the convertor to the cooler. From the cooler the fluid goes to lube the transmission, eventually falling into the pan. It is coolest just before going back into the trans, and only slightly warmer after it drops into the sump. Automatic transmissions operate at around 160 to 175 degrees F. Raise the temp to 200 degrees, and the fluid life is cut in half. Raise it to 225 and it only last 1/4 the time.

 
The tubes in those pans usually plugged up with mud and other road debris, and the network of tubes on the inside made the pans all but impossible to clean properly. I remember these pans from many, many years ago; they were a bad idea then, and still a bad idea, today. Unless you are doing some off roading, stick with a stock pan and make sure your transmission cooler lines and heat exchanger are clean and flowing well. If you switch to an aftermarket high stall, then add an auxilliary cooler to your system. Cooling devices are most effective when handling the fluid at its hottest and that is when it is exiting from the convertor. That is why factory cooling systems pipe the fluid from the convertor to the cooler. From the cooler the fluid goes to lube the transmission, eventually falling into the pan. It is coolest just before going back into the trans, and only slightly warmer after it drops into the sump. Automatic transmissions operate at around 160 to 175 degrees F. Raise the temp to 200 degrees, and the fluid life is cut in half. Raise it to 225 and it only last 1/4 the time.
Thanks Precision Transmission and Don,

Based on this thought process I think I am going to order a deep transmission pan. It seems like B&M and TCI racing have nice pans, so I will look into those. Now I kno why the fluted design did not catch on.

Dave

 
The tubes in those pans usually plugged up with mud and other road debris, and the network of tubes on the inside made the pans all but impossible to clean properly. I remember these pans from many, many years ago; they were a bad idea then, and still a bad idea, today. Unless you are doing some off roading, stick with a stock pan and make sure your transmission cooler lines and heat exchanger are clean and flowing well. If you switch to an aftermarket high stall, then add an auxilliary cooler to your system. Cooling devices are most effective when handling the fluid at its hottest and that is when it is exiting from the convertor. That is why factory cooling systems pipe the fluid from the convertor to the cooler. From the cooler the fluid goes to lube the transmission, eventually falling into the pan. It is coolest just before going back into the trans, and only slightly warmer after it drops into the sump. Automatic transmissions operate at around 160 to 175 degrees F. Raise the temp to 200 degrees, and the fluid life is cut in half. Raise it to 225 and it only last 1/4 the time.
Welcome Precision Transmission!

Precision Transmission has provided great input on the VMF for several years and IMO is a great addition to our group.

TommyK

 
i had trouble getting a c6 pan that was not a piece of junk made in china leaky chrome one.

I ended up getting a pan from a offroad truck site that fit the C6 and was made of VERY thick steel designed to take a hit from a rock when crawling.

it is made of at least 12 pieces tig welded. its the only pan that did not leak because it was super straight and the flanges so thick that you could torque the bolts and the pan would not deflect at all.

unfortunately the place that i got my pan from went away. but if you want something like it, start looking on ford offroad truck sites for C6 parts.

Also i bought mine with extra capacity so dimensionally it is the same as the junk china pans but that is were the similarity ends. also it has no drain plug. which may seem like a bad idea but i had so many leaking plugs over the years this was like a god sent.

 
Need advice... I have developed a slow leak in the seal around my C6 oil pan. It is dripping down from the corner on to the exhaust pipe. Is there a way to stop the leak without removing the pan and replacing the gasket? If I replace the gasket, should I also use a sealant... what type is best?

Also, my pan is a little beat up, so this may be a good time to replace it. Anybody know where to get a good quality stock looking new or used C6 pan?

Thanks,

Rich



 
Last edited by a moderator:
I would make sure it is the pan gasket and not from higher up, like the shifter shaft, and then following the pan to the corner.

Sealer really isn't needed on a good quality pan gasket. You can use something like Gaskacinch to keep the gasket in place while installing it.

 
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