I just recently had a 3" lift put on my 02 Taco and I have noticed that when my truck is decelerating to about 25 mph I get a vibrating feeling coming from the front of my truck. It almost feels like gears meshing hard. There was a diff drop kit put in when my truck was lifted. My questions are these: What would be a likely cause for this vibrating feeling when I am decelerating, and what is the proper spacer heights for the diff drops? I have had an alignment done right after the lift install.

 

try this, grease your driveshaft. i had a similar problem when i slow down i would get a vibration. i greased the rear driveshaft and it went away.

 

I don't think it would be the diff drop. Typically they are 2" OD x 1" tall.

I'd try the following:

1. If it is decelerating, check the brakes, rotors, pads, etc.
2. Tire balancing.
3. Perhaps the lift has settled and you need another alignment.
4. Maybe the lift was not installed properly, if it has vibrated since you did it.
5. Take it to a mechanic you trust or the dealership.

I just put on a OME suspension lift and I had no problems with my ride smoothness afterwards. That was almost a month ago and I'm just now getting around to an alignment, allowing the lift to settle in good. I'd start with the simple stuff and go from there.

Good luck...again!

 

Mine's stock (no lift) and it does it at the when accelerating around the same speed you mentioned (been doing it since I got it -- eight years ago). I'm gonna guess Toyota specs soft diff mount bushings to keep things quiet but, in reality, they wear fast and the front diff torques for and aft so much that the 'shaft binds at a certain frequency (in our cases 25 mph or 40-60 kph). I'm thinking new bushings but not sure how well or if it'll last?