Has anybody else run into this?

I had my gears changed from 3.55's to 4.10's. I normally set up my own gears but I called in a favor so as not to have to do it myself.

I've run into a peculiar situation.

I have an annoying howl at 30 - 40 mph at cruise throttle only. Let off or accelerate and it goes away. Noise is gone completely by 50 and all is quiet on up to max speed. I spoke to Precision Gear and they said that gear whine normally starts at about 50 and gets worse as the speed goes up, which has always been my experience. They were cooperative and of course suggested that I double check the pinion depth and backlash, which I did.

These supercabs have an 80" long, 4 1/2" OD aluminum driveshaft that rings like a bell if you tap it. I'm thinking resonance?

I cut a dozen 1" wide rubber bands from a 3 1/2" OD x 3/16" wall, plain rubber tube and stretched them onto the OD of the driveshaft, spacing them about 6" apart. Bingo! Noise is gone. I realize this may be a treatment rather than a cure but Precision says they will warranty them if it comes back with the damping bands in place.

Anybody else ever had noisy gears that wouldn't get quiet no matter how they were set up?

 

in shop now having pinion bearing replaced,the bearing was resonating down the drive shaft,better have it checked.

 

pinion bearing and carrier bearings,shims and seals...600 bucks...take it in,could be something simple or something like mine or it could get worse

 

I have the same exact thing. I put Precision 3:73 gears in my 2001 Scab and now have the noise at about 40mph with netural throttle. I called reider racing and they said that if the backlash wasn't too tight, which I know it isn't, that it was most likely a harmonic caused by the high grade steel used in the gears. I have 3500 miles on the gears and towed a TT 1500 miles up and down mountains so I don't really think that there is anything to worry about. Good idea with the rubber bands, I will have to try that.

 

I just got a quote from a Ford dealership to rebuild my rearend for $1150 with new parts or about $800 using a used rearend. Did you go to a Ford dealer? I've got a '97 F150 SC with 136,000 miles, the rearend is 3.55 limited slip. If I go with the used rearend is there anyway I can make sure it is a LS before they install it?

Also, I'd thought aout going to 3.73 gears, but with a 4x4 would need to change front and rear. Since I'll be doing the rear, is it worth looking at doing the front as well?

(by the way, this all started because of a whine that has been getting louder and louder).

Rick

 

BTW, part of the favor called in included all new bearings. I now know he set the backlash ot .016 instead of .008 - .010.

I'm fixing it tonight, will post more tomorrow.