Quick, probably dumb questions from a transmission novice

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67fish383S

67fish383S

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So I think I already know the answer, but since this is the first time I've gone inside an automatic trans beyond a fluid and filter change, I want to be sure I do it correctly. I have a 904 that is leaking fluid around the shift lever rod. I have the new seal and it would appear at first glance that the valve body needs to come out in order to remove the old seal from the case. The service manual is not super specific about any of this. It just says "remove the seal from the case with a punch". But then it says you can remove the seal with a small screwdriver from the outside. I don't want to damage the case or the shaft by doing it the "easy way".

So my questions are: 1) Should I remove the valve body or just try to get the seal out with a screwdriver? and 2) If I do remove the valve body, do I then need to replace gasket(s)? I would assume the answer to 2 is yes, but then do I need a full valve body seal kit, or is there a single gasket for just removing and reinstalling the valve body?

Thanks in advance for helping out the dumb guy.
 
Wait for someone to confirm but I believe if you do it from outside you have to hold the shaft up while changing. If you don't you will have to drop the valve body. I did it on a 727 a while back but can't remember ****.
 
You can do it from the outside, but usually headers and exhaust are in the way, and the floor. If you drop the valve body, usually the converter will drain, so you will need more fluid to refill. Usually getting the old one out is not the problem, putting the new one in with the limited space is. But I have done it with out removing the valve body
 
you can get the seal out from the top with a small screwdriver or pick, but it's kind of a fiddly process and there's not a bunch of room for activities in there. but it's doable.

i find it easier to drop the pan, drop the valve body and pop the seal from underneath. throw a fresh filter and gasket on the pan while you're in there.

remember, there is *two* seals in there: one for the gear selector (gear lever) and the other for the throttle shaft (kickdown).

sometimes a groove gets worn into the shaft and you'll need the wider/taller seal which is #22072A
 
If I remember correctly, I used a deep socket and a C clamp to install new seal with out removing anything.
 
I drop the valve body. To install I use a nut and bolt with a large washer above the seal to press them in and it stops right at the case.
 
Thanks to everyone for the helpful comments. Fortunately, room to work shouldn't be an issue for me because I am in the middle of a complete mechanical overhaul of the car ('73 Valiant slant 6). The short block and trans are still in the car, but everything that would normally be in the way is currently not, and I can rotate the engine and trans to make room to try to remove and replace the seals from the top. After reading all of the replies, that will be my first move and I'll only drop the valve body if I have to. Thanks again. I always appreciate the willingness of this group to share the wisdom.
 
67fish383S said:
So I think I already know the answer, but since this is the first time I've gone inside an automatic trans beyond a fluid and filter change, I want to be sure I do it correctly. I have a 904 that is leaking fluid around the shift lever rod. I have the new seal and it would appear at first glance that the valve body needs to come out in order to remove the old seal from the case. The service manual is not super specific about any of this. It just says "remove the seal from the case with a punch". But then it says you can remove the seal with a small screwdriver from the outside. I don't want to damage the case or the shaft by doing it the "easy way".

So my questions are: 1) Should I remove the valve body or just try to get the seal out with a screwdriver? and 2) If I do remove the valve body, do I then need to replace gasket(s)? I would assume the answer to 2 is yes, but then do I need a full valve body seal kit, or is there a single gasket for just removing and reinstalling the valve body?

Thanks in advance for helping out the dumb guy.
Click to expand...
Remove the valve body.
It is not very difficult in a Mopar 904 or 727 and no check balls fall out. It is fairly difficult to get the old seal out while the transmission is in the car and valve body is still in place. Not much room to work above it. You already have to remove the throttle/kickdown lever and the shift lever and once those are off it only takes a few minutes to remove the valve body. Plus, if the valve body is out you can clean off the area where the seal rides.
Here is a video Cope did a while back for another member here. This is how easy it is once the valve body is out.
 
Thanks again to everyone for the helpful info. Even though I probably could have removed and replaced the seals from above, I decided to go ahead and drop the valve body. Seemed to be the better way to do it.

One last stupid question...there is a metal flange surrounding the mating surfaces of the valve body and accumulator piston that continues with a "dogleg" along the front of the housing. It looks like there would be further disassembly required to replace the flange and I'm not sure I've even found the correct replacement part yet. Does it need to be replaced or will it seal again if I reuse it? It seems to be less of a traditional gasket and possibly something that can be reused, but I don't want to put it all back together and have issues because I didn't replace it. Thanks!
 
There was a "special tool" for that seal where you pull the levers and screw it on over the shaft that sticks out of the case, a cork screw type deal that bites into the lip of the seals and draws it out without having to pull the VB.
But yeah other than the park lock rod being a pain (especially when reinstalling) it isn't hard to pull the VB while in the car.
I have a /6 truck with a 727 that I have to change that seal on if I don't decide to convert to a 4 speed instead. That decision is what's holding me back on fixing the seal (I even have seals for that, here) but there's plenty of room on mine to change it in the truck.
 
I bought the special tool and struggled for 45 minutes to get it to bite enough to pull the old seal. I ended up dropping the pan and removing the valve body and I was glad I did. Super easy to get the old one out, and I think made it easier to pull the new one in with a clamp, socket, washers, etc.

Unfortunately for me, once that leak was fixed, it moved to the front seal or TQ, so I decided to have the transmission rebuilt.
 
DigitalRelay said:
I bought the special tool and struggled for 45 minutes to get it to bite enough to pull the old seal. I ended up dropping the pan and removing the valve body and I was glad I did. Super easy to get the old one out, and I think made it easier to pull the new one in with a clamp, socket, washers, etc.

Unfortunately for me, once that leak was fixed, it moved to the front seal or TQ, so I decided to have the transmission rebuilt.
Click to expand...
Oops!
 
A few comments about using special tool.
If you search eBay for this tool, then you will find over 50 listings.
Search terms: Chrysler shifter seal removal tool.
Problem with using the tool on Abodies is lack of room.
Not going to list everything that needs to be removed to have enough room to do the complete job but the most time consuming task are dropping the exhaust and transmission crossmember especially on the v-8's.
Here is a good thread on doing the job. Read post #1 thru #5.
This link is for cbodies where there is much more room to work.

TF 727 "How To" shift lever seal replacement

With help and encouragement from several members, I was able to replace the seal without dropping the pan. I had a trans fluid leak that created a puddle under the car. After cleaning and inspecting, I determined it was the shift lever seal.. I ordered the seal and tool kit but was dreading...
www.forcbodiesonly.com
 
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How deep is the cavity that the seal get's driven into.? I have tapped in a new seal driving the old seal in further with no issues. It was on a GM transmission but it did fix the leak and the old seal stayed in the cavity.
 
67fish383S said:
Thanks again to everyone for the helpful info. Even though I probably could have removed and replaced the seals from above, I decided to go ahead and drop the valve body. Seemed to be the better way to do it.

One last stupid question...there is a metal flange surrounding the mating surfaces of the valve body and accumulator piston that continues with a "dogleg" along the front of the housing. It looks like there would be further disassembly required to replace the flange and I'm not sure I've even found the correct replacement part yet. Does it need to be replaced or will it seal again if I reuse it? It seems to be less of a traditional gasket and possibly something that can be reused, but I don't want to put it all back together and have issues because I didn't replace it. Thanks!
Click to expand...
There is no "gasket" between the valve body and the transmission case on a 904 or 727. There is just a steel separator plate that is part of the valve body. I think that is what you are referring to. No special process or precautions other than make sure it is clean and no big deep scratches or gouges where it sits on the case. Cleaning should NOT include any scraper, sanding, or other abrasive, just solvent and if necessary a rag or plastic bristle brush. If using a rag make sure no lint is left behind. Best to finish with a solvent and blow dry with compressed air.
 
volaredon said:
But yeah other than the park lock rod being a pain (especially when reinstalling) it isn't hard to pull the VB while in the car.
Click to expand...
The park lock is easy if the vehicle is up on stands (wheels off the ground) and you have someone rotate the driveshaft while you are pushing the park lock rod into the transmission case. It is putting pressure on the park pawl and will pop into place easiest when the park pawl can fully engage into the lugs of the output shaft, like when it goes into park.
 
Removing the valve body allows cleaning up the surface that shift seal rides on. Just remove the e-clip, washer, and rooster comb assembly but make sure you don’t lose the shift detent ball and spring.
IMG_1437.jpeg
IMG_1440.jpeg
 
Bobzilla said:
There is no "gasket" between the valve body and the transmission case on a 904 or 727. There is just a steel separator plate that is part of the valve body. I think that is what you are referring to. No special process or precautions other than make sure it is clean and no big deep scratches or gouges where it sits on the case. Cleaning should NOT include any scraper, sanding, or other abrasive, just solvent and if necessary a rag or plastic bristle brush. If using a rag make sure no lint is left behind. Best to finish with a solvent and blow dry with compressed air.
Click to expand...
Thanks a ton. Exactly what I needed to know.
 
toolmanmike said:
www.moparmall.com

Shift shaft seal removal tool for 1960-78 A904 & 1962-84 A727 transmissions

Shift shaft seal removal tool for 1960-78 A904 & 1962-84 A727 transmissions
www.moparmall.com
Click to expand...
I have those tools, and have never been able to use them. Just not enough room above the trans to the floor of the car. I find it easier to drop the pan, valve body, drive the old seal out from the inside, and press the new seal in with a bolt, nut, and a couple of washers. Hardest part is getting the seal to start going in straight. Then clean the pan, replace valve body/filter, pan and refill. Even jerking around, usually done in less than 1 hour.
 
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