727 vibrations = rebuild?

[protocolski]

hey everybody  I have a 72 SE, with a 727 in there.  Sincei bought the car theres been bad vibrations.  I isolated 60% of it to a bad drive shaft.  I replaced that.  The tranny is leaking from output seal and somehwere else up near the bell housing ( i havent ever had an automatic tranny aprat, as i am a college student an dthis is my first resto which is sucking my college funds away ) Engine mounts look ok, tranny mounts look fine as well.  i have been searching around on here and did some of your' recommended tests, i get it to the vib stage and throw it into nuetral, it coasts fine.  so that tells me its in the tranny, at least i think.  also it seems like it shifts too fast when in drive, ie im am not gettig enough out of every gear.  it shifts better when i do it manually with the slapstick from 1 to 2, but then into drive it revs for a sec then shifts to 3.  I am pretty sure its not going into 4 at all.  I apologize for my ignorance,l haha, and welcome all of your wisdom!

[Silver R/T]

how old is trans mount

[dodge freak]

I hate to tell you this but the 727 trans does not have a forth gear. A  long time ago before you were born mid 60's the powergilde trans had 2 gears ,first and second thats it. Then they got high tech and we had 3 speed trans for about 20 years. Automatic trans with overdrive came out  in the 80's and were very week. I would check the kickdown linkage, when its wide open the kickdown should not go back anymore if it does adjust it. If your gearing in back is high like 3.91-4.1 you may want to get rid of the kickdown linkage all together by getting a manual vale body. But have a good trans guy put it in so it dos not shift too hard. I say if you have high gears in back cause it wont shift anymore by it self. It be a pain to always shift. I just leave mine in 3rd gear most of the time, I have 3.91 it takes off OK even in third gear. Even in second I can take off faster than most cars on the road today. Kick down linkage is a pain and if it gets loose you can damage the trans. I put up with it for 6 years till my trans guy said get rid off it. Best thing I did for the trans.

[John_Kunkel]

Since the car has a 727 trans it must be a big block. If the big block happens to be a 400 there could be a problem with the external balance components, someone in the past might have changed out the engine/torque converter and mismatched the parts; this could be the source of the vibration.

[Nacho-RT74]

I would say again driveshaft related... maybe cross bearings worn or unbalanced shaft itself. I'm on a similar deal.

[GreenMachine]

   Your trans mount may look good, but can still cause a vibration. They are readily available, cheap and easy to change. That's what I'd do first.

[MassCharger73]

I agree that the shifting problem is probably a maladjusted kickdown linkage. What size engine is in the car?

[protocolski]

engine size =400, thanks everyone for their advice,  i am lookinginto that shift down linkage this weekend, do u guys know of any tutorials that explain how to adjust it?

[Badbob]

If the rear seal is leaking the rear bushing may be worn, allowing too much play where the front yoke of the driveshaft slides into the rear of the trans.

[Badbob]

Disconnect the kickdown linkage at the carb throttle lever, then (with the engine off) open the throttle and hold the lever all the way back. Then adjust the kickdown linkage so that it is pushed all the way back when the throttle is all the way back. Or see your service manual.

Bob

[71440charger]

i dont recommend driveing it if it vibrates to bad look at the post from me that is what it did to mine lol

[Bandit72]

make sure all of your bell-housing bolts are tight...mine decided to work themselves loose last night and it vibrated really bad

later 

[protocolski]

can i replace that output seal/bushing without pulling the tranny apart, as in taking it out of teh car?