Help with TH400 Shift Shaft Seal
Safety Car
Joined: Jun 2004
Posts: 4,374
Likes: 224
From: Beecher Illinois
And protect the seal when you slip it on.
I just bought ANOTHER for my white79, was going to piggy back it over the other one. I had replaced that one last fall, still leaked.
Upon close inspection, I could see a sliver of rubber peeking out, I had torn it even with my patience installing it.
Pulled that one out and installed the new one. I coiled up a thin flexible piece of plastic inside the seal and slipped the plastic coil over the shaft and slid the seal on and slipped the coiled plastic off. No leaks after a week
Actually, the plastic coil was made from one of those plastic warning tags affixed to the electrical cord of my wifes hair dryer. Happened to be handy.
I think she knows not to use it in the shower
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Put Vasoline on the shaft (and on the edges of the flats) before you install the seal. That will help keep it from getting cut. Work it slowly over the flats on the shaft so that the edges don't slice the seal lip. If you want, you can use some emery cloth or other fine sandpaper to just knock off the sharp edges on those flats. Do not scuff up the shaft journal behind the flats.
Drifting
Joined: Jun 2005
Posts: 1,523
Likes: 1
From: grand prairie texas
A couple of months ago I replaced the shaft seal on my 77 with the turbo 350 transmission and I have a mom & pop transmission place close by me and they just loaned me the removal and insertion tool. I purchased the new seal from A/zone and it looked real cheap and I showed it to that transmission shop and he showed me the seal they use and it was a much better seal and he actually gave the new seal to me also. The problem I had was I could not get the insertion tool lined up straight and I had to remove unbolt my crossmember and lower down the engine and transmission and exhaust system enough to line up the tool. Hopefully yours will be easier. Getting that seal in straight is critical.
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