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post #1 of (permalink) Old 10-17-2000, 08:09 AM Thread Starter
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No input seal on a Jeep T18a?

I have gear oil leaking out of the input of my T-18a. It had contaminated the clutch enough that it was slipping. So I finally had to remove the tranny to replace the clutch and fix the leak. I pulled the front bearing cover off only to find that there is no seal in there at all.
I looked at my '79 FSM (tranny is the original '79 T18a) and according to the break down picture, there is in fact no seal on the input shaft.
So my questions is....what prevents the gear oil from leaking out of that area?
Looking at the teardown picture it doesn't look like there are any seals in front at all.

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post #2 of (permalink) Old 10-17-2000, 08:49 AM
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Re: No input seal on a Jeep T18a?

If it has a seal it is inside the front bearing retainer,(the part the throw out bearing rides on) I bet it is in there. Very early transmissions did not use a front seal, the input shaft had a helical groove similar to a thread machined on it, this groove acted as an archemedies (SP?) screw pump, constantly forcing the leakage back into the bearing area. Later transmissions used a double lip seal inside the bearing retainer. The latest retrofit repair is to use a sealed bearing in the front and rear main shaft, this pretty much eliminates any leakage problems. I think advanced adapters has the sealed bearings. If you go to a bearing house to get these make sure you remove the seal on the oil side of the bearing, you do not want a double sealed bearing, only sealed on one side, but you probably will not find a bearing with the single seal and the snap ring groove.

good luck, jjc

post #3 of (permalink) Old 10-17-2000, 09:48 AM
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Re: No input seal on a Jeep T18a?

my t-18 had the seal in the bearing retainer

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