My truck has developed quite a hum coming from the back. I took a look this weekend at my fiance's parents house and have determined the bearing where the shaft goes into the diff is bad. I've recently moved to an apartment and have no where to work on my truck so I can't do it myself as much as I would like to. Anyone have an idea of how much this is going to run me? I'm not looking forward to hearing the numbers because I know the axles have to come out and everything... I'm pretty bummed, seems like something is always wrong...

Thanks guys.

 

The outer one by the wheel or the inner one like the carrier?

 

Last year I opened up my diff and cleaned it up it was a black mess but still in good shape.

Here is the thing I was shy 1/2 a quart but didn’t think it was going to be a big deal so I ran with it like that for three months one thing I noticed was it was kind of noisy made more of a low pitched kind of gear noise so finally I had a new quart of gear oil and filled it up.

But I read that on the older 8.25 rear-ends the oil hole was place too low and should of been 1/2 an inch higher read this in some off-road mag or something.

So when putting in the oil I parked kind of tilted to one side and put in almost 3/4 of a quart.

You know what my noise vanished I think they were correct more oil is needed for those 8.25 rear ends.

Most aftermarket heavy duty cover plates for the 8.25 rear-ends even advertise that the fill hole is higher up so more oil can be put in the 8.25

You have the newer 9.25 I think but maybe its the same with them look at some heavy duty cover plates on the market they may have a higher placed fill hole also.

 

I already checked the oil level and it was fine.

ramguy, I'm not talking about either of those bearings. I'm talking about the bearing where the drive shaft connects into the diff, the hardest one to get to... The wheel bearings and inner bears are fine. The tires spin like butter.

 

You’re talking about the diff nose or were the drive shaft connects correct.

Yea that’s a complete R/R of the diff if that bearing is bad.

Does it wiggle is that why you think it’s bad, why do you think that’s the bad bearing?

 

I put it up on jacks and the tires spin perfectly fine but turn the drive shaft and you can hear a rough sounding noise that results in a hum at speed. In gear it hums really bad, put in neutral and it almost goes completely away. My fiance's father said it's almost exactly the way his truck was when that bearing went on his truck. I could be wrong, but I think that's it. For my sake I hope I'm wrong because that's the most expensive thing to fix in the back.

 

Oh yeah I know what you mean I must of read it wrong last night. Yeah everything has to come out shafts,carrier and drive shaft.

 

I had a slight hum after i changed my diff fluid but it went away after I put the additive Dodge calls for in it; seems i overlooked it. Not sure if we are talking about the same hum or not..

Would be nice on your wallet if that's all it was but I dunno.. Just saying.

 

I agree as I said pump more oil in it park on a slight side tilt and pump more in its worth a try!!! Or a different oil have you ever dumped your oil?

Royal purple, Mobile1

Its worth a try.

 

It's called the pinion bearing. You will have to remove the drive shaft and and use an impact wrench to remove the pinion nut. Im not sure if on these rearends if the bearing is pressed on the pinion shaft(engages the ring gear) but you will have to replace the bearing and crush sleave. I think you have to remove the carrier to get to all of it im afraid.