To let everyone know before I explain the problem, my Toyota has the original '80 rear axle with 5.29 gears and a Detroit Locker, and has always worked flawlessly until today. Anyway, I was driving home today, on the Interstate doing about 60 mph, nothing out of the ordinary....when my rear differential started to sound pretty bad. The noise is coming from the pinion up near the companion flange and rear drive shaft flange. Then, later, the pinion seal went out, because I've got 80W90 covering the entire back end. Don't be confused though, the noise was there long before the gear oil started dumping, so this noise is not a result of having a low fluid level in the diff.
The noise will NOT happen when I have my foot on the gas, so when there's torque on the pinion it sounds perfect, but the minute I let off the gas, put in the clutch, or am basically coasting or slowing down, it sounds like the whole 3rd member is gonna fall apart. I cannot get it to make the noise in reverse, whether on the gas or off of it. When full-on braking, for say, a sudden stoplight, the pinion is even more noisy and almost starts to ratchet or act like it's getting stuck. I can not only hear, but SEE the entire process in action, because I have no bed, and only a tube cage welded to the frame, so I can look out my rear cab window and down at the diff.
Doesn't this seem like a bad pinion oil seal and a worn pinion bearing to you guys??? I believe this to be true, because of the fact that it is noisy ONLY when off the gas or in neutral. I want some feedback and/or 2nd opinions. Also, I know there are two pinion bearings, the front bearing and the rear bearing (inside the carrier). Would I have to replace both??? If it does turn out to be the oil seal and bearings, I don't have any pullers, anybody who might be in Denver, Colorado want to help me out, or get PAID to do this project for me?? My time is SO limited, I don't even know when i'll be able to get to it. PLEASE HELP!