Excess fluid in tailshaft

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customsportsman

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New Baltimore MI
Hi Everyone,
We have a 1970 slant six three on the tree Dart that we rescued from a 30 year slumber last year. The problem is with the transmission. It is that base 3 speed New Process A 903. Anyway, put a new output shaft seal, and output shaft sleeve. Still leaks a bit.
My question is why the tailshaft is FULL of trans. Fluid? Is that normal? If not, what is the fix?
 
Just to be clear when you say trans fluid you do mean gear oil, right?
 
customsportsman said:
No. The A 903 3 speed manual transmission takes automatic transmission fluid.
Click to expand...
not an expert, but I think the atf in the manual transmission is just a crutch to get better mileage. I don't think you have to use atf. If you use gear oil, it will probably reduce leakage and gear noise. Maybe you are over filling the fluid level.
 
If you have a new bushing and seal and it still leaks, two things to check. Is the slip yoke worn? The back of the slip yoke by the u-joint has a freeze plug- these can leak ATF. That can be sealed with RTV.
 
3/4” below fill plug is an acceptable level to fill most gearboxes, differentials and transfer cases.
Atf used in transmissions was to aid in shifting,especially in cold climates.
Switching to gear oil shouldnt be a problem at all.
 
It is filled to the filll plug dribbles out.
3/4” below the hole - there is no room to check that. Read the service manual.
But yes- 80w90 is acceptable over atf in manuals but a leak is a leak. it’s the yoke, bushing or seal..... or all together.
it’s a 50 year old car. Chances are it’s worn some. Lo!
Syleng1
 
Thanks for the tips guys. I suspect that the slip yoke is worn. I have a used one on now that was better than the original one. That got rid of my vibration last year. I was also filling to the drain plug level; not 3/4" below. I will try that too. A new slip yoke might be an issue though; unless it is the same as a 904. I am going to stick with ATF for lube though. The trans shifts nicely with it; or as nicely as a 903 can shift. Perhaps I should just change to a 230, and make the necessary linkage/driveshaft changes. Maybe someday.

This car is one of those unrestored ones that is kinda beat up, but not too horrible (by Michigan standards), and if I restored it, I think I'd ruin it. :)
 
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