Differential Clunking

[SilentUnicorn]

Elvis has a Differential that goes clunk. This is the second one we have tried in his car. We would like to fix one and make it all better. refering to the moss page i am wondering if replacing the thrust washers (#21) would help? I would think that these would wear out? and cause some slop? The only other thing may be worn axle splines? all of this is considering that the backlash is ok between the ring and pinion.
TIA


mark

 

[jlaird]

I would be willing to bet it is rear U joint rather than rear end, the rear ends are kind of tough.

 

[SilentUnicorn]

It is not the u_joint Jack, Believe me i wish it was. This clunking comes from inside the lump. i do recall noting that the backlash did not seem unreasonable to me, which is why i am asking about those thrust washers. I would rather not have to go that deep into it, if i dont need to. Reading up on the procedure it looks doable , if not a little tedious.

Mark

 

[saabmp3]

Well, if there's a noise coming from it there has to be play in the ring and pinon gears. How often does it make noise? Is there debris in there? Have you opened it up yet and looked?

I have to vote ujoint too, but if you've verified that it's not a ujoint, then a serious look at the ring and pinon is in order.

Off the beaten path here, but I know in a Jeep, a clunk can be associated with various lockers, posi's, LSDs, etc. Any chance you have one of those?

Ben

 

[SilentUnicorn]

[ QUOTE ]
....

Off the beaten path here, but I know in a Jeep, a clunk can be associated with various lockers, posi's, LSDs, etc. Any chance you have one of those?

Ben

[/ QUOTE ]


I wish.

it will clunk nice and solidly when turning it back and forth by hand, with one wheel off the ground, and the driveshaft removed. other hand holding the tire that is off the ground. doing this it will clunk every change of direction. While driving it depends on how smooth or not you are with it.

mark

 

[RobSelina]

worn pinion bearing is high on my list. That's the most common cause of a clunking diff the Jeeps.

Are the splines on the axle damaged? that can be indicative of bad carrier bearings or wheel bearings

The thrust washers on the spider gears are pretty thin and usually dont' wear out. Broken center pins can make a racket, but you'd probably know if that was the problem....

A certain amount of noise is appropriate, especially when turning one wheel back and forth.

 

[Billm]

You may want to look at the flange splines that are right next to the u-joint, that big nut might have loosened and allowed the splines to wear and give you a clunk.
Bill

 

[jlaird]

Out of my depth here, never had a lump go bad.

 

[ChrisS]

Mark,

Have you pulled the diff and coated the crown wheel with white lithium grease and turned the pinion gear to see where it is riding on the crown wheel? This is a quick and dirty test to see if the ring and pinion are mating properly. Do you get a whine at speed when you get on and off the gas gently?

 

[lesingepsycho]

We've owned a few Midgets over the years that sounded like they had two wood blocks smacking together in the rearend. My understanding was always that it was a question of sloppy backlash, although I must qualify that statement by saying that we never bothered to try and adjust it. FWIW

JACK

 

[saabmp3]

ChrisS has the best idea. Put some grease on there and make sure that the pattern on the gears is a proper oval. If you want a good write up, I can point you to a Jeep site (I love Jeep analogies, they're big, easy to work on and simple).

Ben

 

[SilentUnicorn]

Ok Folks , i put some grease on it, and it made some nice even swirls. we have now r+R'd the bearings and pinion gears, as well as the copper washes and fiber shims. Measured lash is now about .013. does any know the lash tolerance?


mark

 

[Bugeye58]

Mark, according to all my books, and experience, the proper lash for a given ring and pinion is on the backside of the ring gear. I'd be surprised if it was anywhere near .013". I just looked at 2 4.22's, and a 4.55, and the numbers were .003", .006", and .004".
Jeff

 

[SilentUnicorn]

Thanx Jeff, this one is marked .008. do you have any other numbers marked in the same location? Next to the .008 it is marked 1583.is there any reason there is not a tolerance range? and why would the lash be particular to any given set? if you know what i mean.


mark

 

[Bugeye58]

Mark, the R&P gears are matched sets. They are lapped together, so the optimum lash figures are particular to each set. If you want to destroy a rear gear in a heatbeat, just change one of the pair. It'll self destruct very rapidly. That's another reason that properly setting the pinion depth is important, because the thickness of the pinion gear, and that of the crown wheel (ring gear) vary due to manufacturing tolerances. There's a very narrow dimensional window where they mate properly. Clunk is usually a function of backlash, while whine or howl is related to pinion depth. I realize that the two dimensions are interrelated, but that's a general statement.
I just looked at the 4.55 again, and on both the ring gear and the pinion are "3653". Those are the match / mate numbers for that set. If you have different numbers on each, then you don't have a properly matched set. Additionally, on this particular pinion gear, it's marked "0", indicating a pinion gear of nominal thickness. This number is important when setting the proper pinion depth, to determine the thickness of shims required to have everything set right.
Jeff

 

[SilentUnicorn]

Thanx Jeff, i am starting to get it. i had forgotton about the hieght dimension, i will get this set back to .008 and see how it looks using the grease method.

mark

 

[Bugeye58]

Mark, I prefer using Prussian Blue for a marker. It's available at any good parts store. Permatex makes it, and it has a lot of other good uses. I like to use it on valve seats, to make sure everything is in order there.
You only should have to mark about 8 or ten teeth on the ring gear to get a good pattern established. Make sure you rotate the pinion back and forth through the marker to get an indication of both acceleration and deceleration, as well as float, or coast.
A good pattern would be about equal on both sides, with the contact towards the outside of the ring gear on the drive side, and equally towards the inside of the ring gear on the coast side.
Jeff

 

[saabmp3]

Alright, so this site is really for a Dana Jeep axel, the pictures are worth a thousand words. Heck, the whole write up is probably the best one I have ever seen about differentials. I would give this a througho read before attempting any differential ring and pinion setup.

Good luck,

Ben

 

[DrEntropy]

Prussian Blue is "Your Friend" when setting up ANY gear lash! Valve seats are the same. A wood mallet (or Snap-On's plastic 'dead blow' one) will prove handy with valve checking too.

Jeff is waay far ahead of me in here now. /ubbthreads/images/graemlins/grin.gif

 

[SilentUnicorn]

Prussian Blue? how about Dykem, commonly used in machine shops.

saabmp3, now thats a site it might take a few minutes to read, great link. thanx