Transmission slipping: Determining fault.

[Kern Dog]

Hey guys...
I have a 904 in my 67 Dart that has been giving me some trouble. The trans was originally in my 70 Charger when I first bought it. It was very clean back then and looked too nice to be original so I assumed that it was rebuilt.
The Dart sits for months at a time. It has not been driven on the street for a few years but I do fire it up and drive around the backyard. Sometimes it acts as if it has no ATF, then slams into gear and jumps to life. To me, this seems like s fluid level issue but the same thing sometimes happens to another 904 that is in my Brother in Law's 72 Duster that is also stored here. Fluid level seems fine and not foamy looking or dirty. It smells okay, not burnt.
When engaged, the trans does not slip at all. When it "slips", it feels as if I am in neutral, not really slipping at all.
It wouldn't be the end of the world if it needed to come out for a rebuild but I'd rather diagnose this as opposed to just jumping to the choice with the biggest expense.
The Duster that has this same issue has a new filter and fluid. The Dart has not had any service in over 10 years, though the miles driven in that time is less than 200 miles.

 

[Kern Dog]

 

[Don Frelier]

Sounds like the converter drains back when sitting. Probably not a big deal. Try driving it every day. I would...

 

[coronet68mx]

X2 with the converter

 

[moparwacko]

Sorry to say Kern, but it is fatal.
Pm me your address and I'll pick it up that horrid car free of charge.
It will take me a week to get there, but hey, I'll do it just for you.



Sweet looking Dart Kern!!

 

[bm02tj]

Add some of that nasty leak stopper and it will soften the seals and maybe help it

 

[Mopars & Missiles]

If its "converter drain back" then putting it into neutral for 30 seconds should make it work fine again. If that's not it, then a plugged or partially plugged filter will reduce the amount of fluid that gets to the pump causing low hydraulic pressure. This will cause "slipping" and/or no engagement of gear selection. If the filter isn't the problem, then you most likely need to make a "band" adjustment to stop the slipping. There are two bands to adjust, the low/reverse and the 2/3 bands. If its slipping only in low and/or reverse and NOT slipping in higher gears that points to the band adjustment. Regardless, adjust them both and while you're in there put a new filter in it also. If all that fails, it gets more complicated (and expensive) real fast.

 

[Kern Dog]

I appreciate the response to the car but I must admit that the paint has faded horribly since those pictures were taken.
The original color:

 

[Kern Dog]

 

[BIGSHCLUNK]

Hell I can't drive anything without "filling " the converter first. As stated put it in neutral for a minute. It will not fill in "park"

 

[Demonic]

The seals get stiff from sitting. Around the yard is not enough, it needs to go out and get up to normal temp for a few hours. Regularly.

Torqueflites are not hard to work on. A few 1/8" pipe to high pressure hose adapters and a good 0-300 and 0-150 psi gauge with a 3" face or better. Pressure test procedures and in the FSM. Tom Hand and Carl Munroe both have published excellent books on 727 and 904 trans.

 

[66Satellite47]

My only experience is with 727's, but they are about the same as a 904. Converter drain back sure could be part of the problem, but if the trans engages and then later starts to slip, sounds like a fluid delivery problem. Plugged filter, bad front pump, poor throttle linkage adjustment. The shift linkage adjustment can do really weird things. Bad valve body (not likely).

 

[Dipstick]

Sometimes it acts as if it has no ATF, then slams into gear and jumps to life.

When converter drain back is the problem it usually doesn't slam into gear it kinda mushes into gear as the converter fills. Sounds more like hardened seals that need a little warmup to seal, try some additive like Lucas that softens the seals.

 

[moper]

Put in neutral for 15-20 seconds before you go into any other gear. Convertor does not fill in park, and they drain back slowly. Not a big deal. Cars that sit will do that fairly commonly.

 

[miller]

How many miles on the thing? Clutches and bands only last so long.

 

[Kern Dog]

Put in neutral for 15-20 seconds before you go into any other gear. Convertor does not fill in park, and they drain back slowly. Not a big deal. Cars that sit will do that fairly commonly.

I do that with this car and my Charger yet this one freewheels then engages like a "Neutral Drop". I should just replace the filter anyway.