Anyone have a diagram that shows the correct location of the inner shaft seal on an 904 transmission speedometer gear? I'm struggling with how deep to push the seal and the metal C clip. Looks like there are two shoulders inside the housing, thus two possible depths for the seal. I have a factory service manual for 1965, but I believe this is a later model transmission so the speedometer gear is different. Pics below show where the seal would contact the speedometer gear itself at the two 'depths' referenced above. When riding on the larger diameter step, the seal is quite snug and harder to turn.
Speedometer Gear Seal
- Thread starter Earlie A
- Start date
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FSM has the procedure. The seals go into the carrier
Duster346
Chris Andrews
The seal bottoms out into the speedometer housing with the lip facing down, and the c-clip goes on top of it. Use an appropriate sized 1/4" socket to push them in.
Refer to the fsm of the year of the trans speedometer gear carrier
Here are some photos I took when I changed out my seal
13 new items by Dana Nance
The fsm says "when the tool bottoms" not when the seal bottoms.
So the depth should probably be determined to be where the seal surface is in the middle area of the mating seal surface on the Speedo gear shaft.
13 new items by Dana Nance
The fsm says "when the tool bottoms" not when the seal bottoms.
So the depth should probably be determined to be where the seal surface is in the middle area of the mating seal surface on the Speedo gear shaft.
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Lots is trans fluid to lube
Duster346
Chris Andrews
It shouldn't fit tight. Can you post a pic of the speedometer housing.
I guess the tool C-4004 might be the key to getting it right. I have it installed now, so we'll see what happens. With the seal all the way down against the shoulder in the housing, the seal rides on the large diameter of the gear shaft, not the small step down.
mopowers
Well-Known Member
From what I recall, it's pretty intuitive. Like Chris said, you simply lube it up a little and push it in until it stops, which puts it right under the c-clip.
Push the seal down till it stops then install the wire clip the same way till it stops then install the gear, it should turn stiff with new seals....
Lon
Lon
That's the way I did it. Seal was pushed all the way in until it bottomed out on the deep shoulder. Then c clip pushed in until it stopped on the higher shoulder (chamfered shoulder). Shaft was stiff to turn.
Last weekend I installed the seal until the seal bottomed in the housing, then pushed the c clip in until it bottomed out on a second shoulder. The speedometer gear was snug in the housing and a little stiff to turn. Today I have a large red puddle under the car. The leak is definitely the inner seal. Looks like I get to try this again. Does anyone know what tool C-4004 looks like (reference the FSM above), or at least how long the tool is? Trying to nail down the seal insertion depth so I don't have to do this a third time.
Inner seal usually just leaks into the cable casing. You sure it's not the outer o ring or the rear band pivot shaft leaking?
It's the inner seal. Trans fluid is coming out between the thumb screw collar and the cable.
In reference to Miller Tool C-4004:
Start seal and retainer ring in adapter, then push them into adapter with a solid 1/2 inch shaft to a depth of exactly 7/16 of a inch. This duplicates what the factory tool does.
Start seal and retainer ring in adapter, then push them into adapter with a solid 1/2 inch shaft to a depth of exactly 7/16 of a inch. This duplicates what the factory tool does.
You are 100% spot on. Don’t know why this didn’t occur to me before now. I have a 727 transmission from a 66 Coronet that has never been modified. I measured the depth of the c clip. It is 0.453 as shown in the pic - so your 7/16” dimension is correct. Thanks for the verification. This also matches Dana’s pics from an earlier post.
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