How to replace 727 shifter shaft linkage seal ?

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Pac J
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How to replace 727 shifter shaft linkage seal ?

Post by Pac J » Mon Mar 13, 2017 12:48 pm

I'm on the way to finish the restoration of my '72 Roadrunner.
After we replaced different seals and connections, unfortunately the transmission is always leaking. This time it is definitely the shifter shaft linkage seal. And it is leaking a lot.
All I found until now is that the transmission has to be taken out to replace the seal ?
Does anyone replaced this seal without taking the 727 transmission out of the car ? Is it possible to do ?
Replacing the seal I could do myself even if it takes time … Taking the transmission out I can’t do myself …
Do I need special tools ?

Thanks a lot for all helpful information, :beer:
Pac

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sdweatherman
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Re: How to replace 727 shifter shaft linkage seal ?

Post by sdweatherman » Mon Mar 13, 2017 2:02 pm

Sorry, my transmission manual is in storage right now. If you do not get an answer here in a few days, post this same question over on www.moparts.org

Unfortunately this forum does not get quite as much member traffic as Moparts. Someone should be able to answer your question over there pretty quickly.

Good luck. Scott.
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Pac J
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Re: How to replace 727 shifter shaft linkage seal ?

Post by Pac J » Mon Mar 13, 2017 2:51 pm

Thanks Scott !

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Re: How to replace 727 shifter shaft linkage seal ?

Post by 71_bronze_gtx » Tue Mar 14, 2017 6:23 am


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rr6pak
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Re: How to replace 727 shifter shaft linkage seal ?

Post by rr6pak » Tue Mar 14, 2017 11:16 am

More advice here. Put your question over on For B Bodies Only, FBBO. They too, can help.

Also, call a tranny shop.

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Re: How to replace 727 shifter shaft linkage seal ?

Post by Moparlar » Tue Mar 14, 2017 11:57 am

^If you pull the pan and the valve body you should be able to knock the old one out and use a c clamp or something like it to pull the new one into the case.. Or even a large bolt and washer to do the pulling of the seal through the hole in the case
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Re: How to replace 727 shifter shaft linkage seal ?

Post by gary » Sun Mar 26, 2017 2:59 am

I Finally bit the bullet after years of small leaks I paid 300.00 at a trans.shop recently. Got new filter and pan gasket too.There are two seals for the shift shaft. You need to find a shop that Knows these trannys. The valve body needs to be dropped.Not a Big Deal if you know what your doing. So far no leaks when parked! :beer:

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Re: How to replace 727 shifter shaft linkage seal ?

Post by plumcrazy71 » Thu Jun 28, 2018 1:00 am

I've replaced the seal 2 ways, 1) dropping the valve body and 2) by just prying out the old seal. Both ways I left the transmission in the vehicle.

Recommend you get a factory service manual if you're going to work on your car!

The shift shaft seal in the transmission case looks like an axle seal with the metal housing. You can buy the seal individually at NAPA or go to a transmission shop. One time I had a guy at a transmission shop give me a seal because he didn't want to waste the time to write up an invoice for it.

If you want to replace the seal between the 2 shafts, there is a small E-clip and washer on top of the manual lever that has to be removed to access the seal. Usually this seal is not the one leaking, causing the puddle on the floor when you park the car!!!

1) By removing valve body: Raise vehicle and place vehicle on jack stands. I like to get the vehicle as high as I can.
Place a large drain pan below the transmission.
Drain the fluid and drop the pan (leave a couple pan bolts loosely installed and tap the pan to break the seal). The fluid will then drain out. Remove the pan and pour the remaining fluid out. NOTE: look for any metal in the bottom of the pan.
Remove the shift/kickdown linkage levers from the valve body.
Remove the valve body, noting where all the bolts go (I put them into a piece of cardboard), and catch the accumulator spring.
Using a hammer/punch (or a screwdriver), drive the seal out the top, being careful to not scratch the transmission case.
Place a floor jack below the transmission crossmember and remove the 4 transmission crossmember bolts/nuts. Leave the drive shaft installed or place a drain pan below the transmission output shaft...or you'll be cleaning up a big mess!!!
Lower the transmission tail shaft far enough to gain enough clearance to install new seal.
Tap a new seal into place from the top, using a hammer and a socket. I think it is a 15/16", but just test fit it on the seal to be sure. A C-clamp (as someone else mentioned could also be used).
Apply a little transmission fluid to the seal lip.
When reinstalling valve body, be sure to reinstall accumulator spring and depress neutral safety switch far enough to clear lever on manual shift shaft. If you don't, you may break the plastic piece on the lever and then you will have to replace it. Tighten valve body bolts to specification EVENLY. Reinstall filter, and pan/gasket.
Reinstall the shift/kickdown levers.
Refill transmission and go for a test drive.

2) Not removing valve body: Raise vehicle and place vehicle on jack stands. I like to get the vehicle as high as I can.
Remove the shift/kickdown linkage levers from the valve body.
Place a drain pan below the transmission.
CAREFULLY pry the seal up out of the transmission case using a small screwdriver. Be CAREFUL to not scratch the transmission case or shift lever.
Place a floor jack below the transmission crossmember and remove the 4 transmission crossmember bolts/nuts. Leave the drive shaft installed or place a drain pan below the transmission output shaft...or you'll be cleaning up a big mess!!!
Lower the transmission tail shaft far enough to gain enough clearance to install new seal.
Apply a little transmission fluid to the seal lip.
Tap a new seal into place from the top, using a hammer and a deep socket, tall enough to clear the shift/kickdown levers. I think it is a 15/16", but just test fit it on the seal and shift lever shaft to be sure.
Reinstall the shift/kickdown levers.
Refill transmission and go for a test drive.

Hopefully this helps...I'm sure there are a couple details I may have missed, but this should get you through the process.

Chrysler had a special seal remover tool, but I don't know if they are still available anywhere. They were part of the transmission tool sets that the dealerships had.

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