August 2, 2010 11:23 AM Subscribe
AutomotiveFilter: Please help me diagnose this squeak in my 99 Ford F150.
posted by werkzeuger to travel & transportation (5 answers total)
This is a 1999 Ford F150 XLT 4WD with automatic transmission and the 4.2L V6 gas engine and short cab. It has only 53k miles on it. Also, I believe this vehicle was in a flood before I bought it. There's a lot of corrosion up to a certain level on the underside, and then none above that line.
About a year ago it began developing a squeak that seemed to come from right behind the cab, like it was coming up in the crack between the cab and the bed. The squeak is fairly high pitched, about 1kHz, and is definitely connected with the drivetrain:
Engine on, in park, revving engine = no squeak.
Engine off, in neutral, manually moving rear wheels = slow squeak.
Engine on, in drive, moving at a slow speed = squeak that varies with travel speed, but is too fast to be 1:1 with wheel rotation.
Okay, so I'm thinking U-joints, especially with the flood history. I try to listen to each u-joint individually with a cardboard tube as a helper rotates the rear wheels and driveshaft, but I can't pinpoint a problem joint. So I bite the bullet and remove the rear driveshaft between the transfer case and differential, and the u-joints feel fine. Silky even. Reinstalled driveshaft. Checked ATF, transfer case and differential fluid levels. All fine. So I pulled the rear axleshafts out of the differential. They're fine, riding in an oil bath from the differential like they should. Parking brakes aren't rubbing either.
Flash forward to now. The squeak is far more persistent and clearly is tied to the movement of the driveshaft. Also, it's making that clunk when you go from drive to reverse that, to me at least, screams U-Joint.
So...should I just replace the U-joints? I'll take it to a shop if I have to, but you probably can tell by now that I really like to DIY, and a set of U-Joint bearings are cheap, so I thought I'd query the hive mind.
P.S. No the current U-joints don't have a grease zerk.