vibration in the rear end

I have an 08 2.7L regular cab 4x4 tacoma with 38,000 miles on it. I bought the truck with 500 miles on it. I installed a 3 inch tough country lift with the add a leaf in the rear six months ago. Every since i installed the lift I here a grinding vibrating noise somewhere in the rear half of my truck when I let off the gas pedal or push in the clutch when im going over 55 mph. When im pushing on the gas pedal i don't get any noise and the truck sounds fine. I only get the noise when im coasting or off the gas. I thought it might be the driveline angle because of the lift so i installed 3 degree shims, but the shims did not solved the problem. The rear differental is stock and all i've done to it is change the oil 8 thousand miles ago to full synthetic, so i can not imagine that is the problem. Has anyone had a similar problem or does anyone have any ideas what is makeing the grinding vibrating noise? Thanks

 

could be tranny?

 

this is kinda a grinding vibration noise that comes from my tranny at low rpms

http://www.youtube.com/watch?v=zkfKzNr-NwM

 

I know exactly what you are talking about. I had this same problem after I installed my revtek lift and drove with it for a couple thousand miles. I became very annoyed with the noise and began reading the forums for solutions. Someone on the TTORA forum suggested switching (fliping end for end) the rear driveshaft to solve the problem. It worked like a charm and I haven't had a problem since. Before I fliped the driveshaft I took the truck to Gresham Toyota and they said it was the rear differential. They replaced the rear Differential assembly under warranty, this didn't fix the problem. Fliped the shaft end for end and it worked like magic. The single cab Tacomas are the only ones you can flip the driveshaft end for end because they only have single cardon joints on each end of the shaft. Good luck, took me an hour to do it myself.

 

Hey thanks for the info. I'll try fliping the driveshaft.