2000 I4 2WD Auto thumping, frequency increases with speed
Hello Ranger-Forum message board,
I'm trying to diagnosis (and fix) my father-in-law's 2000 Ranger 2WD I4 automatic pickup.
I recently drove it (about 2 weeks ago); there's a thumping that started ~10 mph and increased with engine speed to the point that it was just a constant very noisy thrum. I thought it was coming from the front driver-side area of the car.
I (mis)diagnosed it as the worst failing front wheel bearing I'd ever heard... I was able to take a closer look at the vehicle was last night. I tore into the DS front wheel bearing... To my surprise, everything looked great. Apparently he'd had the front bearings done a while back (but forgot?). I replaced the bearings, races, and seal on the DS front anyhow and put everything back together. Drove it around my neighborhood and nothing has changed. Still the incessant thumping that increases with speed, noticeable at about 10 mph and getting really noisy by 30 mph... I didn't drive it any faster. Problem NOT solved.
Crawled back under it with the rear-end on stands, tried to rattle the driveshaft around but both of the U-joints seemed solid (and looked newer). There's fluid (and no leaks) in the rear differential that was replaced ~18 months ago when I replaced the outer bearings in the rear axle.
Put the truck in drive, had my brother-in-law depress the throttle to the point where we can hear the thumping and crawled back under the truck. I wasn't keen on putting my face near the drive shaft, but the sound seems like it's coming more from the front of the transmission rather than the rear. Do torque converters ever become unbalanced?
There's a leak from the rear main or transmission input area of the engine (I should have tried to figure out if the fluid was oil or transmission fluid, but I didn't).
Spent the morning searching google and this message board for similar problems, but have turned up nothing.
I won't get to mess with the truck until the next time he's down to visit, but would like to have a good solution to this problem.
So... Anyone ever experience something similar? Please let me know. Thanks!!!