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Rear driveline / axle noise

Carl

Bronco Guru
Joined
Aug 8, 2006
Messages
1,035
Loc.
Aurora, IL
My 1975 Bronco makes a humming or light grinding noise only when decelerating or coasting. It doesn't happen when I have my foot on the gas and the engine is under load. It sounds like it's coming from the rear axle area.

I know the easiest thing to do is check the u-joints. I kind of looked at them when I was under there and they looked ok, but didn't really inspect them. I'll be sure to check them again.

When I bought the Bronco, the owner said that there were some bearings in the rear axle that needed to be replaced and he gave me a box with new bearings and seals in it. I searched and read this thread:

http://classicbroncos.com/forums/showthread.php?t=79679

Someone mentioned that if there is a noise from the rear axle on deceleration, it is most likely the pinion bearings that are bad. Is this correct? How hard is it to change these bearings? Or at least take the diff. apart to determine if they are bad? Should I take it to a qualified mechanic? I have never messed with a differential, but that's never stopped me before.;D
 

spatacuulous

Full Member
Joined
Mar 21, 2005
Messages
169
Loc.
philadelphia
I don't know what to tell you, but I figured I'd help by keeping you at the top of the pile. I did have a noise only when I would let off the gas pedal in my 66 and it turned out to be the Drive shaft itself. Good luck:cool:
 

SteveL

Huge chevy guy
Joined
Jun 24, 2001
Messages
11,602
Loc.
Hawthorne ca
I would check those u-joints again. With no load on the driveshaft grab it and see if there's any play. If so change em. Also if you change em get the stock spicer replacements. The ones the local ap stores don't hold up as well.
 
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