I did a search of topics on this site going back over 20 years, and looked at the FAQ, and I cannot see where this question has ever been satisfactorily answered.

What size O ring goes on the end of the park cable on an early 904 transmission? I ask because, for years, mine has leaked. I have replaced it numerous times. One time I discovered that I had a tiny, hairline crack in the Park Lock Housing and thought "ah ha! So THIS is where it was leaking from!" Indeed it was leaknig there. I have replaced that cover, I have replaced the cable, I have put numerous brand new O rings on it, and still have to place a pan under it to catch the expen$ive leaking fluid. The O ring I am using is called "R-04" in the box set. It has an ID of 5/16", an OD of 7/16", and a cross section of 1/16".

Since this standard size has utterly failed to seal my, and many other people's park cables, I think it is time to consider the possibility that Chrysler used some oddball size for this application.

Does anyone have the specs for a 904 that might shed some light on this. I have 5 of these cars and would be happy to buy a sack full of them to finally solve this ongoing, years long nightmare of a leaking Park Cable.

Thank you in advance for your learned help with this.

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1961, 1962, 2X 1963's and 1965 Valiant 200. one of the '63's has been shortened by roughly 3 feet. The `65 is a `vert.

I always did a schmear of Ultra Blue or Ultra Black silicone and did not have leaks.

Lou

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Home of Slant6-powered fun machines since 1988

If you absolutely can't get a proper seal you could try this idea. Go metric. 5/16 is 7.9375mm........7/16 is 11.1125mm.........and 1/16 is 1.5875mm

You "might" be able to fit an O-ring with the specs of 7mm ID/11mm OD/2mm thick. The added thickness of the O-ring will likely make it quite snug on the cable. Just a thought. Make sure you get EPDM or nitrile.

The size I posted will be a little too small for the cable (as per your spec) and a little too small for the bore of the trans BUT with the extra thickness of the rubber it likely will expand enough to be tight on the trans.

I am sure someone can chime in on a proper source for the exact correct item.

Thank you for your replies. Isn't it nuts that we are still guessing after all these years?

There has to be some reference for 904 specs that would tell us the exact size for this critical part.

I tried a metric size once, but it still leaked. At least I don't have to drop the pan every time. I long since replaced my stock pan with a larger one with a drain plug. It's still a hassle though. In order to put sealant on it, as Dart270 suggests, you have to drain the transmission and thoroughly clean the bore of the park lock cover and the cable. This takes time. The one time I tried it, I had to let it sit over the weekend. Maybe it sealed the cable, but we will never know because that is when I discovered the hairline crack. I guess I will be doing it again. So tired of wasting time on this one problem.

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1961, 1962, 2X 1963's and 1965 Valiant 200. one of the '63's has been shortened by roughly 3 feet. The `65 is a `vert.

Has anyone tried wrapping the end of the cable in a couple of layers of Gasoilio, then installing the ring? Or should it be the ring first, then wrap the ring and cable? Either way, the goal would be to add a couple of mics to the diameter of the ring and, hopefully, force a seal. Would it work?

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1961, 1962, 2X 1963's and 1965 Valiant 200. one of the '63's has been shortened by roughly 3 feet. The `65 is a `vert.

You can jack the car up in front and let the trans fluid drain toward the back, then pull the cable housing partly out, then clean it, then apply ultrablue/black. I do not remember the fluid thing being an issue, so I assume this is what I did w/o draining the trans. To me, this kind of repair is exactly where good gasket sealer shines and can save you tons of hassle.

Lou

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Home of Slant6-powered fun machines since 1988

So I ended up taking it all apart again and adding that magic "schmear" of glop, in this case the stuff designed specifically to seal transmissions. I am pleased to report that after a full weekend of driving, the park pawl housing and park cable is no longer leaking.

I am disappointed that we still have not solved the mystery of exactly which size O ring Chrysler used to seal that assembly to begin with. At least I can quit placing a pan under it.

Thank you for your help with this.

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1961, 1962, 2X 1963's and 1965 Valiant 200. one of the '63's has been shortened by roughly 3 feet. The `65 is a `vert.

Glad that worked! Enjoy the leak-free cruisin...

Lou

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Home of Slant6-powered fun machines since 1988