New Problem 84SD trans problem
 

Just finished installing the engine and trans in my '84 SD. It's good to have the oil leaks fixed but now I have this odd problem. The car shifts great but when put in N from R or P from any other gear I get a terrible shutter/clunk. Wasn't there before I removed the engine and trans. I am trying to post a video to show what is happening but am having trouble posting it.

Looking at the drive shaft while the car is running and someone moves it through the gear selections you can see the shaft "rattle" pretty well. New flex disc at the trans end. The one on the chunk end is fairly new too. The drive line seems tight. Trans shifts great as I stated earlier. I dunno. Gonna have to study on this one.

So fluid levels have been properly adjusted since you installed them ?

On the installation of your engine...

did your FSM instructions involve making a ' shop made' measuring item... for placing your engine relative to the engine mounts in the proper place ?
and if so... did you do that ?

fluid levels
 

Yes sir.

fluid levels
 

Yes sir.

Did you see the question about the home made alignment tool?

I did
 

But I got trigger happy on my phone and submitted my reply. My finger stuttered too. That's why I replied twice.

I do not own a FSM. This is the 3rd engine install I have done and have never known about a "measuring device." The other two installs happened without any hitches. Please tell me more about this device you speak of. Thanks!

Were the engine and transmission mounts replaced? How is the diff mount?

Mounts
 

Those were actually the first things I checked even though all the mounts are new. There's no motion/shutter/rattle/vibration/chatter in the engine or differential. The drive shaft is where all the chatter is. I have a hunch that the internal splines on the transmission output shaft yoke may be worn.

Is the center bearing OK? Was the shaft taken apart and reassembled out of balance?

Did you take the shaft apart without putting a mark on each piece so it could be put back together exactly as it was ?

Unless you know for sure that the shaft is balanced, don't assume that it is. When I replaced my center mount and bearing, I was careful to mark both pieces. Only problem was that it wasn't balanced in the first place. Driveline shop and $125 later, I know it's balanced.

drive shaft
 

the drive shaft was never taken apart. It stayed intact the whole time.

He said it was a new problem...

and "Wasn't there before I removed the engine and trans."

so my question was logical.

Think about what's happening. .. shifting out of R causes noise.
So R is winding up somehow.
Does it happen only when parked or does it happen when moving?