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C6 leak
The C6 gearbox is leaking, I found a kit with a seal and an o'ring.
Don't know which one is leaking.
What is the best an easiest way to do the job?

Also, I found this lock "something" pin disconnected, and don't know if it has been disconnected on purpose. If not, should I put it back in place?
Thank you.
The lock "something" pin is your steering column lock. It won't allow you to remove your key until the shift lever is in park, nor can you move the lever out of park without the key in the ignition and engine started.

I'd strongly suggest spraying the transmission with a degreaser and then power washing it. Then pull the trans pan, valve body and replace the shift shaft seals. reassemble with a new filter and gasket.

That should take care of any pan leaks
If its the shift lever where you have the leak you will have to remove the tranny pan and the valve body. The shift lever can only be removed from inside of the case and you will be able to replace the seal for both the downshift lever and the shift lever at the same time. You can't take off the nut that holds the lever in place with that valve body on. I tried to but could not get in the wrench to remove the nut. It a messy job but the good thing is that it can be done with the tranny in place and is easy to do. You will also need to do the NSS adjustment when you do this replacement.

That disconnected rod looks like part of the mechanism that locks the steering column when the car is in park and key removed. Also locks the shift lever. My guess is currently you can turn the wheel and shift the transmission with the key out of the ignition.

Edit: RacerX posted his reply while I was writing up my response. but is saying the same thing that I said

Edit 2: I found a video on how to do this on a C4 tranny and it is very similar. The only difference is the bolts that you need to remove the valve body from the transmission for the C6. You only want to remove the bolts to get the valve body out and not the ones that bold the body together. Mustang medic had a video for the C6 but I can't find it now. For this video it start at around the 4:30 area but again its for the C4.


351C 4V cc heads, 10.5 : 1 CR, 290 Herbert cam, Flat top forged pistons, forged connecting rods, Atomic efi,
C6 with Gear Vendor overdrive, 3.89 Tru Trac, Hooker Super Comp with 2 1/2" Pypes Exhaust.        

Some Mod pictures can be seen at:

Mine is leaking through that same place and was given similar recommendations. NPD has all those seals.

1971 M-code Mach 1

        [Image: 20160929_171923_edit2_small.jpg]

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump
Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes
hate to say it,, trans has to come out to fix that properly. you can fudge the repair to replace the seal and it will just leak again.

the o-ring you can swap but that rarely leaks. usually its the seal has dried out, worn out, started to leak around the lever.

leak stop will do more damage.

truth is it isn't that bad to drop the transmission without taking the engine out.

usually all the other seals in the transmission have had it as well.so its a chance to rebuild the transmission totally then install it back in the car.
there are 25+ other seals inside that dry out and go bad also.
Hmmmmm, ok, I leave the engine on and drop the C6 down. I'm waiting for the shop manual for the C6, with this I have to do this job, hope to replace evry part where it should go, I know it's not an easy job, actually I never worked on an automatic transmission, will be funny time

Jbojo, I saw this movie, should be similar to the C6. But now after reading 72HCODE post, I better tear down the transmission, this car had poor maintenance, if even minimum maintenance have been done.
Hi John i just Love this video They are so funny guys 😀 Regards Lars DK73

Sendt fra min D2005 med Tapatalk

So I'm a proud owner of one Mach 1 73! Regards Lars DK73whistling
step 1 : I highly recommend buying this video.
buy a package with a ford 9" rear end also.

step 2 get some c6 rebuild manuals to follow along with the video.

step 3 you will need some special tools if you find the bushings need to be replaced.
you will need some special tools to replace the end seals correctly on the C6
these tools are going to run you a couple hundred bucks.

you will need a C6 spring compressor to put the reverse piston together.

there are 2 different tools for the end seals.
and 2 different tools for the end seal bushings.
you can use a seal driver set, except you will need some special sizes for the bushings and those will cost lots of money like 300$
you will need snap ring pliers and a set of picks to get the seals out.

i rebuilt my c6 this summer by myself, i spent 800-1000$ between tools and parts.

i never did a transmission before, it was not hard but you need to work carefully you will always find a problem and you may need replacement parts. i had to source a bunch of used parts, i needed 4 transmissions to make one good one,,, no joke.
[Image: 0fdd06160053b98cc11cb6a0b437a342_zpsdo5whcgw.jpg]

i forgot the OTC tool numbers i used but there was 4 or 5 different tools i bought specific to the C6 and i needed extra tools because i used post 1977 parts in my 1973 transmission. you need a seal protector for post 1976 transmissions.

get that video first from bad shoe.
After 45+ years of turning wrenchs, I put away my big blue Snap-on (mustang) tool box. I rebuilt more transmissions then I care to think or dream about and I still have transmission tools in my tool boxes that I bought years ago and never used. If you are going to rebuild your C-6 yourself? rebuild it to the specs for police/taxi, in other words, HEAVY DUTY, you do not need to build a neck snapper unless you like whip lash or broken "U-joints" or are planning on racing it. I rebuilt the C-6 in my 1977 Ranchero in 1988 just after I got it as it had a soft 1-2 upshift and have only had to replace the front seal since then because it sat for several years with out driving it. Use VASOLINE (petroleum jelly) to lubericate the seals and NOT THE GREASE FROM YOUR GREASE GUN during rebuild and air test all clutch packs BEFORE you install them. handle the valve body separator plate like a new born baby, 1 little scratch in the wrong place... the pressure build up in the wrong circuit (300+ PSI) bleeding over will not make you a happy camper. A machine shop can make most seal drivers needed or a socket can work in a pinch. AND TAKE YOUR TIME during assembly and air test,air test and air test all of your circuits
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