Well, today my car did the damndest thing. Was rolling about 80mph and i started to feel a little shimmie in the front. Spent a couple miles doing the accel/deccel thing to try and pinpoint it. I couldn't really determine what it may have been then it got bad. It shook enough to make me worry and pull off the road.
Got out and checked all the lug nuts, and they were fine. Pulled back out onto the highway at a decent clip with no problems. Then just as i stop accelerating it comes back in a small way. Spent the next couple miles in slower moveing traffic trying to do the whole pinpoint thing again to no avail. It was doing it on or off the gas. Pulled off the interstate and gingerly continued to my destination. Now going 30-40mph and still doing it. I had to play with the gas peddle to keep just the right amount of load on the drivetrain so it wouldn't shake or shimmie. To little or to much load and it would come back. Its fine at idle or no load conditions.
I make it to my destination which the car sat for about 30 minutes. When i get back to the car i check the fluid to make sure it was good and under the it for anything unusual. It all checked out ok so i started back home. This time i kept it under 40 the whole way back. Funny thing is that the vibrations didn't come back until 30 minutes into a 40 minute drive. Then when it did come back it was just a small vibration.
I did figure out that it will not vibrate at any speed as long as i'm in neutral. I didn't check first and second gears for this problem but i do know that 3rd and OD definately do it. This is the first time i have ever had this happen. It has HD axles in it that where serviced less than 2 yrs ago. It seems to be fine for the first few minutes/miles after it sits, then it comes on gradually.
At first i was thinking that one of the axles was slipping, or a clip had fallen out and was allowing an axle to bounce around. That was before i put the car on the jack. Checked both sides and the back/forward rotation slack is .25-.5 inches(didn't measure it) with no side to side play of the wheel hub or axle. Even tried to manhandle the axles around to no avail. There just isn't any play. All shock mounts are fine. All tie rods are secure. No play in anything. And yes, the motor mounts are fine.

The only thing i could find that made me wonder was there seemed to be a bolt missing from the tranny. I don't know if it is actually missing or there is not ment to be a bolt there in the first place. This is in the row of copper anodized looking bolts that mount the tranny to the block. The head of these bolts faces the driver side. Don't really think that wuld be it, but you never know??? The tranny is still mounted up securely to the engine block at rest. Don't know if there may be an issue though cause i can't put a load on it and be in the engine bay at the same time.


So to summerize i have good motor mounts, HD axles that were serviced less than 2 yrs ago, no slop in the drivetrain; yet i get vibrations(sometimes drastic) when there is a load on the DT. Feels like a tire out of balance then progresses to what i would suppose it would feel like if both front tires were out of balance. Tires are brand new with a balance and alignment recently done. And no i haven't done anything to upset that.


Anybody have some trouble shooting tips?

 

To much useless info in that post.....

Does it feel like engine misfire vibrations or is it comming through your steering wheel indicating wheel/tire or suspension issues?

A little more technical info would help.