My t-case has been buzzing ever since I got this thing running/driving. It doesn't do it on acceleration/deceleration, only when I am barely pressing the throttle to maintain speed. I took a short video of it and posted it below. The sound speeds/slows as I am going up and down hills, and I can feel the buzz when I put my hand on the shifter. When I press the gas a little more, it completely goes away. I've read some other threads that said the shifter bushings could cause rattling, but mine are fine. Everything is nice and tight, nothing seems out of place. It makes the sound in 4wd as well. Any ideas?

 

Rusty - not sure if you have a chain driven case or gear driven so I don't know if there are any specific issues to check for with a chain driven case, but start with checking the fluid. What's the condition of your u-joints? Check them for play and lube the grease nipples.

 

Sorry I forgot to list specs. 91 4Runner with (I believe) an A340H trans. U joints had no play from what I could tell, but I will get under there again and give them a good tug and greasing. I thought this transfer case shared fluid with the trans?

 

Two different fluids. The trans is actually in the front and connected to t-case via the small drive shaft. I had this same issue and when I got underneath and shook the driveshaft that goes to the rear diff, it was a little loose. Turns out my output shaft bearing in my t-case was bad causing the driveshaft to wobble. You can also check to make sure your driveshaft is balanced.

 

I have a 90 Toyota PU 4x4 with an A340H trans. I just replaced the output shaft seals. The t-case on mine uses transmission fluid and is chain drive. There are some that use gear oil. Look inside the drivers door frame for manufactures tag , It will tell you what trans you have. You might just need to add fluid.