Technical Mopar 727 Question

Hi folks,
I'm currently installing a 440/727 combo in a custom project (58' Dodge). The drivetrain came out of a 73' Imperial that was running until a few months ago with no issues. When I hooked up the prop shaft I noticed that the tranny want turn in reverse direction ( engine not running) . Its locked the same way in reverse as its in park position, rotates fine in forward. I started the engine this weekend and fwd gir and park is normal ( wheel up from the floor). I had several issuse with the carb and ignition, so didnt run it too long and didnt shift to reverse, but I expect the engine to stall. Expect from park, it shall be possible to rotate the shaft freely both ways when engine not running if I havent missed anything. The combo has been install in the frame a few weeks and if I not remember wrong, I could rotate the tranny shaft both ways earlier and it suddenly change its mind all by itself. Any idea what the problem might be..? I change filter and oil in the weekend, old oil looks good.

 

Did you separate the trans from motor? Or was the combo together and reinstalled in your frame?

 

When this happens...it is usually just the sprag holding it. Should be fine when running.

 

It was never separted, landed in the frame as it came from the Imperial..

 

It may very well be so, Im not familiar with the internal lift of these tranny's . Its like a mechanical lock ( like in park position) so Im just worried that I kill something by putting it in reverse... This combo came out a Imperial that caught fire on the highway so I dont think I bought something with hidden gems inside either..

 

It should be harder to turn in one direction than the other, but it should not be impossible to turn.

 

Curious problem to be sure, it should rotate. After you started the engine did you try again to manually rotate the prop shaft? Did you try to shift into reverse while it was running?

On a side note, I see that you have an aftermarket carb...be damned sure to continue using the linkage that originally ran from the carb to the trans (part throttle kick-down)(throttle pressure governor). Driving the car without this linkage properly adjusted will kill the trans.

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I tried to rotate the shaft after it run for a while, but same issue in all position. Had to disconn the prop shaft to get her back into the garage. I didnt use any force, but its not like a clutch ready to slip, just a solid stop. Thanks for the heads up about the linkage, I do have all the org. parts for it. I didnt tried to shift to reverse when running, the Lokar shifter linkage hits a tranny cooler tube so prevent it to go full back against the rear. Same issue in neutral by the way.

 

How does it act if you disconnect your shifter and just shift it with the lever on the transmission?

 

Thats more or less what I did as the Lokar shifter is only partly hooked up, only the linkage that connects direct to the lever was on at that time. Feels like in park position in reverse direction in all positions.

 

I'm sure it's fine, just put in on he ground and move it . Same deal as when up on a lift and turn one rear wheel by hand the other side turns in the opposite direction in a non-posi rear. You didn't change anything so why would it be different?

 

You didn't mention about the fire. Did some 20-something roll back driver drag it on the truck in park and maybe jam the park pawl/gear?? Or maybe somehow ruin the sprag itself. Who knows at this point.

 

That could have happen.. a shaken driver and a tow truck guy that consider that fried Imperial boat to be a lost case.. I check one more time when I get the engine to run smooth before I rip it up.

 

An update in this issue after I got the engine tuned. Still not been on the road, but when jacked up it spins freely in all fwd gears and reverse without noise, but its seems to take slightly higher rpm to start moving in reverse. But the same problem remain - In reverse its still holding when trying to push the car backwards with or without the engine idling. Its feels the same as in park and we have to disconnect the driveshaft. It rolls smoothly in fwd gears and the park postion works as it should. Any ideas beside ripping it out..?

 

Rip it out. Either the fire, or the tow after the fire damaged the trans. For all you know, it may have been slammed into reverse or park to stop the car so the driver could get out and watch it burn. There may be enough screwed up parts inside it may not be worth rebuilding, might be cheaper to build another trans.

My luck with installing used automatic transmissions usually results in getting them rebuilt before I have something I can use. Gene

 

Used engines seem to treat me the same.
So does this drive down the road and back up?
Or is it just that you can't push the car backwards?

 

Have you checked the band adjustment's?