/6 904 transmission swap still having problems....

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firefighter1

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Hello everyone,

I recently had an automatic 904 transmission go out.. Or at least I think that's what happened. Please give me your opinion on the symptoms I had. All of a sudden I had no reverse when in gear. Also at freeway speeds the engine was revving very high, but I was not flooring the gas pedal. This seemed to happen all of a sudden, not gradually.

I have replaced the torque converter within the last three months, so that is relatively new. I swapped out the transmission with my buddy a couple days ago in my garage. Everything is working, however when in drive, occasionally I will be at a full stop and when I begin to accelerate the car revs higher than normal and then kicks hard into gear and goes forward. This is an intermittent problem, doesn't always happen. I check fluid levels and shifter linkage. Everything appears to be good. What do you guys think is the problem? Did I swap a bad transmission for another bad transmission? The new transmission is another 904 identical to the one I replaced. The car is a 1971 dodge dart swinger 225/6 with 904 tranny and 7.25 rear. Any information or help is much appreciated. Thank you all! Mopars rules!
 
did you adjust the throttle pressure (kickdown) rod correctly? it sounds like you put in another lazy trans if the fluid is completely full.
 
Sounds just like an old worn out trans with hardened rubber.
Especially if it gets better when it's warm.
 
check to see if you have engine braking in manual low. if you do, the front clutch is bad. and that would cause your high revs in drive and no reverse.
 
Your original trans. had a burned up front clutch pack or bad seals in it. Either way it wasn't working properly.

Even though you replaced the converter with a new one 3 months ago you ran it in a bad trans. that most likely filled it with clutch pack garbage. You should never use a converter from a bad trans. in a good one unless you have it professionaly flushed out. I'd drop the pan and see if the filter is plugged. It's possible all the garbage from the converter plugged the filter. If it's not that it's what TB said which is the new trans. has hardened seals and if it hasn't been rebuilt it wouldn't surprise me. Remember, the last 904 was made well over 20 yrs. ago so it's nearly impossible to find a good used one unless it's been rebuilt.
 
Another possibility is that the shift selector linkage is not correctly adjusted. If it's revving high, that probably means it's not shifting out of second (or if it's revving really high, it's not shifting out of first). Perhaps when the shifter indicates "D", the transmission is actually in "2" or "1". That could also explain the lack of reverse; perhaps when the shifter indicates "R", the transmission is actually in "N".
 
Hey ; firefighter

the symptom you are discribing is like a second or third gear start, witch would be caused by a hanging govenor assembly or sticking valvebody.
the easy way to tell is when it does it pull it to manual low and see if it takes
off right, if it does drive vehicle at 15 to 20 mph and do several manual 1-2 and 2-1 shiftswith shift lever , this should free up gov. or sticking v/body.

good luck; Lon Kopaska (transmission master tech) DSM. IA.
 
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