904 flexplate alignment - no 1/8” hole. What should I do?

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azaustin

azaustin

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I’m getting ready to pull the cable-shift 904 in my ‘65 Dart GT 235HP. The old tranny is almost ready to come out. According to the factory manual, there should be 1/8” hole in the flexplate that you align with the arrow mark on the torque converter. My torque converter has the arrow mark, but the flex plate has no hole. I’ve marked it with a black sharpie so I can align it with the new torque converter going in. I’ve looked closely on every part of the flex plate web, and there is no 1/8” hole anywhere. Any advice on this from you 904 gurus our there? Pictures of my flex plate, TC, and FSM attached.

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Two of the ears have red paint on them. You can see it on the right one in this picture. I just wanted to make sure everything was where it should be. I figured if I put the new TC in the same place as the old one it would be ok. The new TC has the arrow mark, so I’ll just put it where the old one was. My old tranny works fine and had no issues other than leaking ATF out about as fast as you could put it in. I’ve swapped C6’s, E4OD’s, TH350 & 400’s, but this is my first Torqueflite, so I want to avoid any self-inflicted foot wounds. Thanks.
 
azaustin said:
That’s kind of what I got from the FSM, but if that is the case, why does it need to be marked?
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So you can figure it out a little quicker. Good lord man, just paint one leg of the flex plate white with a corresponding white mark on the converter. This ain't brain surgery.
 
azaustin said:
That’s kind of what I got from the FSM, but if that is the case, why does it need to be marked?
Click to expand...

Being marked saves you from putting bolts in it and turning the converter only to find out you have to turn the converter again to take them out again.
One of the bolt holes is offset.
 
Sorry for asking a dumb question. Just wanted to make there weren’t any balance issues, etc., since this is the first one of these I’ve worked on.
 
azaustin said:
Sorry for asking a dumb question. Just wanted to make there weren’t any balance issues, etc., since this is the first one of these I’ve worked on.
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It was not a dumb question. MANY guys don't know that, and to complicate, the later EFI Magnums had symmetrical bolt patterns on the flex.

The reason they are indexed, is that if the engine is externally balanced, the weighting on the LA engines is on the torque converter. On the later Magnums, the weighting is on the flex plate
 
I guess I should have mentioned that the transmission had been rebuilt before I got the car and I was afraid the wrong flex plate (or torque converter) might have been installed. As I mentioned earlier, the transmission worked okay, but just leaked a lot. You never know when someone has tweaked something to get by, and I’m not at familiar with torqueflites.
 
azaustin said:
Sorry for asking a dumb question. Just wanted to make there weren’t any balance issues, etc., since this is the first one of these I’ve worked on.
Click to expand...
It wasn't dumb at all. Sometimes those of us who've done things for forty years or more are a little short sighted.
 
No. I’m replacing it with a rebuilt transmission I bought (off this web site) several years ago. The original owner had it rebuilt by a reputable shop in Phoenix, but decided to go with a 727 because he was installing a large displacement blown motor in his car. When I received the tranny it was complete with a rebuilt TQ and sealed in a large plastic bag. I may rebuild the original trans someday as a learning experience. It was leaking out of the front pump seal, output shaft seal and the pan when I got it, as well as the park cable oring and speedo cable. I I fixed the oring and pan leaks, but then it was pretty obvious the front seal was really the big one. When I bought he car the seller though the transmission was bad, but I was pretty sure it was the neutral safety switch, which it was. The car idled too fast, which made it jerk going into gear. Fixing the idle took care of that. The front seal leak wasn’t too bad when I got the car, but it got progressively worse.
 
What year is the replacement trans, is it a 65 cable shift also ?
If it's a later trans torque converter will have a larger diameter pilot going into crank and won't interchange without a special converter made-up. Old converter won't fit in later trans due to different split counts.
Lon
 
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