TH350 leaking gear selector shaft seal/replacement

Gear selector seal replacement....

Not sure if this will be considered ok to post, or a casualty, but here it goes.....here is my step-by-step pictorial on how I changed out my leaky shift shaft seal. I searched high and low on the web and couldn't find any complete how-to's, so here is mine in case anyone needs it.

First, you should grab this tool to make the job easy:

 

Then, here are the next steps: remove the shift arm from the shaft, install the tool onto the old seal....tap it on with a hammer, then....

 

Snug it up with a wrench....not TOO tight though, just enough til you feel the tool bottom out.

 

Then install the bolt and snug it up against the shaft. The tool will start to pull out the old seal.....

 

The tool will extract the old seal...

 

Make sure there isn't another old seal in the bore. an old trick on some of these trannies is to install 2 seals to stop a leak. With the seal out, it's time to clean the bore to make sure there is no foreign matter in there. I like to use a Q-tip soaked in laquer thinner, and get it good and clean.

 

Time to grab a new seal. I like to dab some axle grease on it before installing it. Be careful not to nick the seal on the shaft detents or you'll be doing this again soon. I also run some emory paper on the shaft to make sure there are no burrs to catch the new seal....

 

sweet !where did you buy that tool?ive never seen one

 

Here's the installation tool in the kit. A 1/2" deep socket would work too. Just "set" the seal with a few light taps with a hammer til it sets. Don't Harry Hamfist it in, or you'll distort the seal....

 

With the seal installed, the shift arm is re-attached and the trans is re-filled with ATF. Voila. Start to finish, this job took 15 minutes, and that's with taking the time to take these pictures. Of course, i did this job up on my 4-post lift, which makes it super simple.

New seal is $4, the tool is $9. The result is a priceless clean garage floor again.

 

Got the tool (I lent out my old one and you know how that goes, lol) from my local NAPA store.

 

Good tech. I have done at least a cupple hundred of them over the years.
Thay make that tool for the mopar trannys also but not as much fun doing them.

 

..so, you drain the trans fluid first?

 

I did, yeah. Before I did this work, I replaced the steel pan with one of those finned aluminum ones, they come with a drain plug, which makes emptying the trans a breeze.