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
 
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.
 
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