Posted by David on August 19, 2000 at 01:56:40:
I needed to get my 251 rebuilt due to some excessive rod knock. I put the engine back in a week or so ago and got it running. (It really purrs now.) However, when I try to accelerate in 3rd gear the thing shutters like its about to fall apart. (2nd and 4th shutter a very small amount also, but nothing like 3rd.) It didn't do this before the rebuild. The shuttering is not related to letting the clutch out - i.e. it shutters when my foot isn't on the clutch pedal and is most pronounced when trying to accelerate - i.e. loading the drivetrain.
My thoughts are centering on a pressure plate, friction disk, bent transmission input shaft, or a U-Joint. I did have a lot of problems getting the input shaft aligned with the pilot bearing and you could say the trans was hanging by the input shaft a few times. Could this really screw it up that much? Because its much more pronounced in 3rd, and doesn't seem to affect shifting - I am not as inclined to think clutch.
Any help would be much appreciated.I