High Speed Vibration Question

[e50095]

I have a 93 LX automatic that is completely stock. Under load at 65 mph, there is a driveline vibration that drives me nuts and forces me to slow down. If I put the car in neutral though, it disappears instantly and coasts sweet as can be. Drop it back into drive and it makes me have to poop in about 10 seconds. My question is, since the vibration only occurs when in gear, can I assume the driveshaft and rear axle cant be the issue, given the axles and driveshaft are still spinning when I put it in neutral and coast? It is trukly serene coasting at 65 in neutral. The tranny mount seems to be good, Is it possible the inout shaft gear on the tranny is bad, but the seal hasn't gotten around to leaking yet?

Any advice you can offer would be truly appreciated...

Ken in Pa.

 

[Noobz347]

Swap out both drive shaft U-Joints. Use sealed units (non-greaseable).

 

[foxera93]

have u found watt was wrong ,eye have the same problem except mine is a 5 speed,eye can only go to 76 then then the shifter starts to vibrate the faster the louder

 

[jrichker]

1.) Check to make sure that the yellow paint marks on the driveshaft line up with the yellow paint mark on the rear axle flange. If the don't, unbolt the rear U joint and align the paint marks.

2.) Do the U joints replacement as advised, and when you put it back together, make sure the yellow paint marks on the driveshaft line up with the yellow paint mark on the rear axle flange