Rear diff growl

[Radish150]

My rear diff makes a bit of a growling noise upon deceleration, also there seems to be excessive play in where the driveline inters, I can move it around quite a bit, though the play in the rotation of the yoke does not seem excessive. My question is if there is any chance that this noise is just due to bearing´s or "adjustment" , or if I´m likely looking at a whole new differential?

thanks.

 

[Degnol]

I would check the pinion bearing. The stake nuts have been known to come loose. Is it leaking gear oil at the pinion?

 

[Poser]

My rear diff makes a bit of a growling noise upon deceleration, also there seems to be excessive play in where the driveline inters, I can move it around quite a bit, though the play in the rotation of the yoke does not seem excessive. My question is if there is any chance that this noise is just due to bearing´s or "adjustment" , or if I´m likely looking at a whole new differential?

thanks.

I would remove the drive shaft and see what is going on.


If the ring and pinion are damaged, then yes, you could be looking at spending a lot of money on this.

 

[Radish150]

whats the diff

Degnol no, no leaks... thanks (on the other hand, maybe it´s just empty ).

Durka, you must mean remove the drive line and dissasemble the differential right? I cant imagine what good just taking the drive line out would do, if Im mistaken please enlighten me.

Well, at least its sure that a worn ring-pinion would not result in excessive drive shaft play, that would result in noise yes but more of a rotational sort. Ok yeah I know, it will have to come out, hoping on bearings and adjustment.

cheerio

 

[Cruiserdrew]

This sounds like a worn out pinion bearing. Very common in my (limited) experience.

You may be able to buy a bit of time if the pinion nut is loose. What happens is the pinion bearing wears, the preload goes down and eventually the nut is loose. If you tighten the nut you have not solved the problem, just taken out the play. The pinion bearing is still worn out and the looseness will return.

Replacing the bearings will mean a full tear down. The set up of the diff is something to have a pro take care of, since it does take a bit of time and skill. You will be surprised at how much this costs. The diff bearing kit is $125-$150 and the set up is $200+. If you need a new ring and pinion, that's another $200 or so.

 

[Herb]

You could keep it simple and relatively cheap by finding a donor front differential (usually seen less action than rear) and swap it in. That is what I did....they are interchangeable.

I had the same problem, except my "growl" turned into a "clunk" and the pinion bearing shredded. It turned out that my stake nut had become un-staked and allowed the pinion to be pulled into the diff. It all started with a growl though.....

 

[Radish150]

You could keep it simple and relatively cheap by finding a donor front differential (usually seen less action than rear) and swap it in. That is what I did....they are interchangeable.

I had the same problem, except my "growl" turned into a "clunk" and the pinion bearing shredded. It turned out that my stake nut had become un-staked and allowed the pinion to be pulled into the diff. It all started with a growl though.....

Okies, all excellent and practical advice. I like the front switcheroo idea... right up my alley! Wonder what that old guffer will sell one of his dead diffs for?

Oh, well while were here I should ask what of these front diffs wont fit (guess I sorta asked that bass ackwards) ? Is this something that didnt change over the years? OH, and what if they were left outside and got rained on, will the rust kill them? I know the bearings should not rust... dissasemble, clean and reassemble? Sorry I know that last question will give some of you an uncomfortable feeling .

Cheers mateys.

 

[Radish150]

Just forget I said that part about the bearings not rusting ok?

 

[subzali]

Poser suggested to remove the driveshaft so that you can get your hands directly on the pinion flange and check for play. You also have direct access to the pinion nut at that point, so you can check to see if it worked its way loose and can tighten it like CruiserDrew said. Those two things are really easy to do and help you to figure out whether you need to tear into the thing, because tearing it all down isn't really a picnic. Yes a worn ring and pinion COULD result in excessive driveline play, if somehow the backlash got messed up. You don't say what year your truck is, but a differential from a early-'78 40 series will swap in just fine. You don't state where you're located, but in the US 79+ 40 series had 3.73 differentials, as did 60 series trucks. So ultimately if/once you get your diff out and it is determined that it needs to be swapped, count the teeth on the ring and pinion (37/9 for 4.11 gearing) and make sure that matches with what you're swapping in.

Oh yes and the bearings WILL rust if left out in the weather - they're ferrous metal after all...

 

[Radish150]

Cool, thanks.