Can yhere be vibration from rear end?

[Street Fighter]

I have a 77 camaro that I have done every thing I can think of to get rid of a vibration I have at 80mph and on.there's no leak on the rear end so I felt that it could not be the cause.How never when I get on and off the gas I feel the slack in the rearend.I tried to move the yoke up and down or in and out but I can't find any slack.can this be the problem even doe there is no movement of the yoke or there is no leak on the rearend.Again I will state that I have done all that there is to do to find this problem.driveshaft balanced,new ujoints,trans mount,motor mounts,checked rear axles,wheel bearing,balanced tires. need help please.

[Sarge]

Auto or M6?

[nolimits]

check the backlash on the gears, they're probably just worn out.

[Street Fighter]

The trans is a automatic. There is no noise coming from the rearend.Do you still feel that it could be the rear still?I really would like to get this problem behind me so that I can move on to other things I wanted to do to the car. thanks for the info.

[Street Fighter]

After thinking about the statment you gave, there my be some truth to what you have said. I have noticed that there is alot of movement of the yoke when I took my hand and turned it from left to right.You my be on to something. Once again thank you all.