Vibation

[richamer1]

I have a slight vibration that I am tracking down. Did not think it was tires but did put a different set on. About 50 MPH on up no worse as speed increases. Felt it was in the rear of car. No steering wheel vibration but see it in the rear view mirror. Up on jack stands I feel it with the drive shaft in and do not with it out. It could be the drive shaft but I don't think so. Good U-joints and nothing changed there. I have a 7.5 3.73 Posi. I think that is my source. I have not taken anything apart but it seems like a lot of play at the pinion yoke. Looking for suggestions when I get in there . I do have a dial indicator from my machinist days. I am looking for an 8.5 but have not found the right one yet. Price location etc. So I want to fix what I have for now. Car is a 461 BBC with a Muncie. I do not hammer on the 7.5 much at all . Thanks

 

[t5montecarlo]

Did the pinion nut loosen up?

 

[richamer1]

I will check it.

Did the pinion nut loosen up?

 

[LS6 Tommy]

It could also be the transmission output bushing...

Tommy

 

[bracketchev1221]

If you have vertical or horizontal play in the pinion, that is the vibration.

 

[Tony_SS]

Let us know what you find out..

 

[richamer1]

I have made some progress. Pinion nut is tight. Very limited movement in the pinion yoke side to side and up and down. Same with transmission output shaft . So I did have the driveshaft balanced. Said it was off quite a bit and I see the weights they put on. I would say that the vibration is about 60 % gone. Still there but much better. Seems to be a lot of backlash in the differental when I rotate the pinion yoke back and forth. Probably not related but I am going to open that up and set it.

 

[t5montecarlo]

There should be no movement side-to-side or up-and-down. If you have limited movement, you have too much.

Too much backlash may be problematic, too.

Keep us posted.

 

[richamer1]

Seemed like there was about.030 play in the ring gear. Took it apart and there was 1 shim on each side. .235 on dirvers sdie and .245 on passenger. What do you think about just reversing right and left shims and rechecking. I was expecting several smaller shims on each side.

 

[t5montecarlo]

Try it and see.