FMX transmission shifter seal replacement how to

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mach1000

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OK finally got a little time to document how to replace the leaky FMX transmission shifter seal and kick down O-Ring. Sorry I didn't document bolt head sixes but you'll really only need a wrench for the nut on the shifter assembly and kick down, a socket set to remove the pan bolts and valve body and a screwdriver and few other tools I'll describe below.

Since the drain pan on most FMX's don't have a drain plug I preferred to pump the oil out from the dip stick tube using a cheap hand pump and some tubing you can get at the local hardware store. That way I don't get oil gushing and dumping all over the place splashing and making a mess. Plus I pump it into a container that easy to pour back into the trans when I'm all done.

IMG_6831.JPG

I like to have a nice clean area on the work bench ready to go with to work on with a couple layers of old newspapers to catch the oil mess.

Unhook the kick down rod, the steering column lock rod and the shifter linkage from the trans.

Drop the oil pan. I still keep plenty of newspaper and a catch pan under the trans to catch any oil drips and when the times comes to remove the valve body you'll get more oil dripping.

Once the pan is off the sediment if any and gasket surfaces can be cleaned up on the pan and trans housing. I have the super strong little magnates I like to drop in the back of the pan to help keep the fluid "clean".

Remove the oil filer and bracket that holds it in place. Many times these are just screen type filters and can just be cleaned and reused.

There are two metal tubes the are hooked into and under the valve body that need to be removed. I just pry them out with a flat blade screwdriver. They are a real pain. Take note of placement.

IMG_6837.JPG

Next remove the valve body bolts. There are two metal tubes that are just friction fit between the valve body and the rest of the trans.

The valve body will then come out. Keep an eye on the bolt lengths. I believe they were all the same.

IMG_6836.JPG

More oil will be dripping so keep plenty of paper towels on hand.

I set the valve body, bolts and tubes aside.

Now you can get to the kick down nut and shifter nut.

IMG_6840.JPG

Use a box end wrench to remove the both nuts on the inside of the trans. You can just hold the outside of the kick down and shifter with your other hand.

Once the nuts are off you can slide the kick down and shift lever out the side. Watch out because there is a plunger and spring that will fall out of the trans housing shaft once you remove the shifter.

IMG_6847.JPG

Also take note of how the kick down and shifter fit into each of their respective parts inside trans. Take a picture if you need to. They will need to go back in the exact same way. It’s not difficult but hard to describe.

I took both of them to the bench and cleaned them up with carb cleaner and steel wool.

You'll need to replace the kick down O ring with a new one. I use a little petroleum jelly to help it slide on.

The shifter seal is pressed into the side of the trans. I used a small flat blade screw driver and a pick to pry it out.

IMG_6846.JPG

After making sure the hole was clean I put just a skim coat of The Right Stuff sealant around the new trans seal and set it into place.

Best way to drive the seal back in while the trans is still in the car I found was to use a putty knife laying flat against the seal. Then I tapped it in evenly with a small hammer. This gives you enough room to drive it in with the hammer.

IMG_6842.JPG

Now the fun part. Getting the spring and plunger to stay up in the shaft while getting the shifter back in. After lots of swearing I figured out to use a dab of petroleum jelly on it and stuck it back in the shaft. That held it long enough to get the shifter in and in place.

Also I found it helpful to put the shifter inside the car in part if it wasn’t already, loosen the nut on the linkage and manually move the shifter on the trans in park so everything would be lined up correctly. Then tightened everything up. You’ll see the Park pin inside the trans and how it locks into the teeth to give you Part.

Then slide the kick down shaft in, replace the nut.

Again make sure the kick down and shifter fit into each of their respective parts inside trans. Take a picture if you need to. They will need to go back in the exact same way. It’s not difficult but hard to describe. You can move each by hand to make they are a functioning correctly.

Just reverse the rest of the procedure noted above.

Note to check the trans pan mounting surface. Many times it may be warped from overtightening. I lay it gasket surface down on a nice flat surface and use a body hammer to flatten it out if it is warped. You can use a straight edge to check as you go along.

I used a new cork gasket and used a thin layer of the right stuff on the pan surface before I set the gasket on it.

Don't overtighten your pan bolts. They just need to be snug. You can tighten them more if you find a leak once you run your car a bit.

Note that you’ll likely need more trans fluid than what you pumped out since you’ll lose some from the valve body and it just dripping out as you work on it. Also rubber gloves with a textured surface for grip are a must. Don't forget to check your fluid again in park while hot and engine running to make sure you're topped off.

I would say it’s a medium to advanced job. If you can’t change brake pads don’t attempt this.

This isn’t comprehensive but meant to give you an idea of what you’re in store for in changing these seals out. I would also refer to the Ford shop manual.

IMG_6844.JPG

IMG_6848.JPG

 

Bentworker

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Excellent!

I'll be looking at this later, I need to replace the kick down lever on my FMX.

 

mach1000

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I'm not sure why the picture got rotated when I added them to the post. They look a little funny. Any questions feel free to ask. I've done this a couple times.

 

Mac

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I'm not sure why the picture got rotated when I added them to the post. They look a little funny. Any questions feel free to ask. I've done this a couple times.
Thank you very much for taking the time to document and post this info. Any and all help is greatly appreciated, especially since I will be changing my seal in the near future.

Mac

 

Ron Tanzi

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gauge package.rim blow steering wheel,15" magnum 500s,351 C 2bbl running a 4bbl Holley 600,MSD 6a with stock distributor and Pertronix,Comp cam mild grind, The Engine(rebuilt by me in 2002 for the second time the first rebuild I did was stock in 1995) made 305hp and 358 lb ft on the dyno. 9" 2.75 rear end,Global west sub frame connectors,620 front coils.Rear defroster. My parents bought my car brand new the year before I was born. I cherish it like my child.
Great tutorial. Everyone with an FMX thanks you.

Ron

 

c9zx

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Thank you. Chuck

 

m-rvin

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Thank you for the write. I have FMX trans I replaced same shifter seal. When I unclipped the 2 long springs (little and big) a small barrel fell out. Not sure where that goes?

 

mach1000

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Thank you for the write. I have FMX trans I replaced same shifter seal. When I unclipped the 2 long springs (little and big) a small barrel fell out. Not sure where that goes?
This part was mentioned in my write up "Now the fun part. Getting the spring and plunger to stay up in the shaft while getting the shifter back in. After lots of swearing I figured out to use a dab of petroleum jelly on it and stuck it back in the shaft. That held it long enough to get the shifter in and in place" It's pictured with the spring in one of the pics. Hope that helps

 
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Dave

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New to the forum, but the proud owner of a leaking FMX. Really appreciate someone letting me know where to start for a fix. Unfortunately it is not in a Mustang but settled in with a 351c in a 1960 Jaguar MK IX.

 

mach1000

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New to the forum, but the proud owner of a leaking FMX. Really appreciate someone letting me know where to start for a fix. Unfortunately it is not in a Mustang but settled in with a 351c in a 1960 Jaguar MK IX.
Most likely as outlined above the shifter seal and o ring. Pan gaskets also leak because the pan flange isn't flat and people just crank the bolts down tighter making it worse. But if you drop the pan you might as well replace the shifter seal and o ring.

 

MaineToDC

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Great write-up and pictures, Mach1000. I'm in the process of doing this very job and am about to put everything back together (just got the shift selector seal out tonight). I wanted to asked if you remember which way the plugger (pic 5) goes back in. The spring goes first and then the rounded or flat side against the spring? It looks like the rounded side is slightly worn so I assume it faces out and the flat end goes against the spring? Thanks for any insight you might have.

 

mach1000

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Glad it helped! Flat side against the spring

 

waterlife

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I know this thread is older, but with the valve body down, why didnt anyone take the valve body apart and clean the journals with Q-tips?

 

summerboy

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thx for the description, helped me a lot. I am now at the point to get the shifter seal out. Think I have to remove the exhaust pipe as well, otherwise I am not able to pry it out. No room for using a screwdriver. Cheers from Europe, the Netherlands.

 

Rbouwma

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OK finally got a little time to document how to replace the leaky FMX transmission shifter seal and kick down O-Ring.  Sorry I didn't document bolt head sixes but you'll really only need a wrench for the nut on the shifter assembly and kick down, a socket set to remove the pan bolts and valve body and a screwdriver and few other tools I'll describe below.

Since the drain pan on most FMX's don't have a drain plug I preferred to pump the oil out from the dip stick tube using a cheap hand pump and some tubing you can get at the local hardware store. That way I don't get oil gushing and dumping all over the place splashing and making a mess. Plus I pump it into a container that easy to pour back into the trans when I'm all done.

I like to have a nice clean area on the work bench ready to go with to work on with a couple layers of old newspapers to catch the oil mess.

Unhook the kick down rod, the steering column lock rod and the shifter linkage from the trans.

Drop the oil pan. I still keep plenty of newspaper and a catch pan under the trans to catch any oil drips and when the times comes to remove the valve body you'll get more oil dripping.

Once the pan is off the sediment if any and gasket surfaces can be cleaned up on the pan and trans housing. I have the super strong little magnates I like to drop in the back of the pan to help keep the fluid "clean".

Remove the oil filer and bracket that holds it in place. Many times these are just screen type filters and can just be cleaned and reused.  

There are two metal tubes the are hooked into and under the valve body that need to be removed. I just pry them out with a flat blade screwdriver. They are a real pain. Take note of placement.

Next remove the valve body bolts. There are two metal tubes that are just friction fit between the valve body and the rest of the trans.

The valve body will then come out. Keep an eye on the bolt lengths. I believe they were all the same.

More oil will be dripping so keep plenty of paper towels on hand.

I set the valve body, bolts and tubes aside.

Now you can get to the kick down nut and shifter nut.

Use a box end wrench to remove the both nuts on the inside of the trans. You can just hold the outside of the kick down and shifter with your other hand.  

Once the nuts are off you can slide the kick down and shift lever out the side. Watch out because there is a plunger and spring that will fall out of the trans housing shaft once you remove the shifter.

Also take note of how the kick down and shifter fit into each of their respective parts inside trans. Take a picture if you need to. They will need to go back in the exact same way. It’s not difficult but hard to describe.    

I took both of them to the bench and cleaned them up with carb cleaner and steel wool.

You'll need to replace the kick down O ring with a new one. I use a little petroleum jelly to help it slide on.

The shifter seal is pressed into the side of the trans. I used a small flat blade screw driver and a pick to pry it out.

After making sure the hole was clean I put just a skim coat of The Right Stuff sealant around the new trans seal and set it into place.

Best way to drive the seal back in while the trans is still in the car I found was to use a putty knife laying flat against the seal. Then I tapped it in evenly with a small hammer. This gives you enough room to drive it in with the hammer.

Now the fun part. Getting the spring and plunger to stay up in the shaft while getting the shifter back in. After lots of swearing I figured out to use a dab of petroleum jelly on it and stuck it back in the shaft. That held it long enough to get the shifter in and in place.

Also I found it helpful to put the shifter inside the car in part if it wasn’t already, loosen the nut on the linkage and manually move the shifter on the trans in park so everything would be lined up correctly. Then tightened everything up. You’ll see the Park pin inside the trans and how it locks into the teeth to give you Part.

Then slide the kick down shaft in, replace the nut.

Again make sure the kick down and shifter fit into each of their respective parts inside trans. Take a picture if you need to. They will need to go back in the exact same way. It’s not difficult but hard to describe. You can move each by hand to make they are a functioning correctly.

Just reverse the rest of the procedure noted above.

Note to check the trans pan mounting surface. Many times it may be warped from overtightening. I lay it gasket surface down on a nice flat surface and use a body hammer to flatten it out if it is warped. You can use a straight edge to check as you go along.  

I used a new cork gasket and used a thin layer of the right stuff on the pan surface before I set the gasket on it.

Don't overtighten your pan bolts. They just need to be snug. You can tighten them more if you find a leak once you run your car a bit.

Note that you’ll likely need more trans fluid than what you pumped out since you’ll lose some from the valve body and it just dripping out as you work on it. Also rubber gloves with a textured surface for grip are a must. Don't forget to check your fluid again in park while hot and engine running to make sure you're topped off.  

I would say it’s a medium to advanced job. If you can’t change brake pads don’t attempt this.

This isn’t comprehensive but meant to give you an idea of what you’re in store for in changing these seals out. I would also refer to the Ford shop manual.
 

Rbouwma

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Thanks for the info, I will be doing this to my 1970 Mach1 fmx very soon

 

69 Rustang

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I fought my way through this job today.  Rounded up the parts locally and installed them.  The shift detent pin was a bugger.  Then the U-shaped tube would not go back in for anything—fought that for a good 40 minutes.  I filled it up, took it around the block to make sure it still shifted and then cleaned up my garage.  I just finished rinsing Type F out of my hair—it is so soft and manageable now, my wife is jealous.  

 
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