Gramozeka

Hi,

I am about to open up a differential and check things out, I don't have any whine/vibration but I have a clunk when applying gas from coast, it gets more noticeable as car worms up. All mount replaced and and everything else is checked out, i.e there is no noticeable play in pinion shaft. I have been told it's just slack in the drive line.

Additional symptom, there is a low growl heard from rear when doing a left lane change hard at 40 mph. Could be carrier bearings. nothing for right lane change.

Getting in there I want to check the gear pattern, visual inspection of differential and backlash.
What is a proper backlash for a stock 01 auto v8?(all faqs list backlash for aftermarket gear sets)
Is there way to check carrier bearings without taking out the differential?

Thanks

theskitztikwon

iTrader: (18)

backlash is the distance between your ring and pinion it sounds like your carrier is going bad but i could be wrong

Gramozeka

theskitztikwon: Thx for reply, what I mean is what is the measurement suppose to be for backlash... I have seen numbers from .006-.012.

I measured backlash today, it was .012-.013. I was unable to obtain gear marking compound, so no pattern available. Putting dial gauge on ring gear horizontally and prying differential I was able to deflect the gauge +/-.001". Are these measurements normal?

I can try to attempt gear pattern with grease, should I do it or should I buy rebuild master kit?

..another great idea just visited my head, I can attempt to re shim the carrier.

Any advise would be helpful, thanks.

theskitztikwon

iTrader: (18)

check the gear pattern first also i think the factory grears are AAM look them up

chevelledave

iTrader: (5)

Backlash is fine @ .012 ...was setup around .008 or so new ... .001 deflection is not a problem ...check your U-joint if you clunk on decel,, also check your wheel bearing if your hearing a growl when switching lanes ...There really isnt to much load on the carrier bearing as the are supported in the carrier ...axle bearing carry to load of the car ...carrier bearing carry the load on acceleration...I do non destructive axle testing (we tear up a lot of **** for ND testing ..lol)..we rarely see carrier bearing failures ...and as far as "resetting up the gears " its almost an exercise in futility the gears are already worn with the existing pattern...

chevelledave

iTrader: (5)

here ya go ...new specs

RG Diameter 7.50"
10 3/8" X 18 RH Threaded Bolts
PINION Diameter 1.438", 27 Spline
CASE: 3.08 & Down, 3.23 Numerically Higher

8620 Material Heat-Treated

Assembly Specifications:

Cover Bolt Ft. Lbs. 20
Pinion Bearing Preload In. Lbs 24-32
Pinion Bearing Preload In. Lbs 8-12 Used
Ring Gear Backlash .005-.009
Ring Gear Bolt to case Ft. Lbs. 90
Side Bearing Caps Ft. Lbs. 60

Jays_SSZ28

iTrader: (2)

From my experience if you run the max backlash it will make clunking noises, and it can be adjusted tighter without issue.

As far as carrier bearing wear, I pulled my 2002 apart for a gear change at 31,000 miles and found the left side bearing race ate up approx 1/3 of the way around. And it made no noise at all.

On my other car around 89,000 I had a front hub bearing get noisey. It had no play, no noise spinning it while jacked up, couldn't really tell where the noise was coming from but replacing the hub got rid of it.

Gramozeka

Here are pictures of pattern

http://picasaweb.google.com/10365565...at=directlink#

According to online articles this pattern seems to indicates incorrect backlash. Please correct me if I am wrong.

The shims If I remember correctly are .2425 on the left and .240 on the right.

the ring gear looks good, with some white discoloration on the edge of some teeth, it's like a speck but I can't feel it if I ran my finger over it.

no significant metal shavings,

bearings & races looked ok.
oil was crystal clear.
car has 85k miles of probably hard driving... not done by me
I could not detect any play in the pinion or u joints.

I am thinking about replacing wheel and differential bearings and re shimming the differential to about .008 backlash. And but everything back together

Do you think this is worth while doing? I am not doing this for racing, I need a reliable transportation that is faster than average car.
If yes does anyone have appropriate shims?

Jays_SSZ28

iTrader: (2)

That grease isn't working at all.

I found one brand of oil paint at walmart in a tube, they only had it in white but it's the exact consistency of real gear set up compound. Get a brush while you're there.

Gramozeka

Thanks Jay for quick reply, The differential is out of the case and I want to put everything back together labor day weekend (if I new it was such a hassle to get gear marking compound I would have bought it from GM two weeks ago when I got differential additive). So I got to make all the decisions now and buy shims off of some one here.

I have uploaded some more pictures (all taken at the same time with my cellphone), maybe looking from a different angle you will get a better perspective. Since this is the first time I am doing gear marking for the coast side I did not apply any resistance so the imprint is sloppy, but still visible.

http://picasaweb.google.com/10365565...at=directlink#

In my inexperienced eyes I have a picture perfect Top heel contact & Top toe contact from, which means I need to decrease backlash.

www2.dana.com/pdf/5717.pdf

Than again I was there and I have a bias agenda of getting it finished.

If more people will agree that means I go ahead.

My original shims are .2425(left) and .2400(right) together they add up to .4825

To reduce backlash from .012 to .008 we use a multiplication factor of 1.42 (I read this somewhere)
As a result I need new shims of 0.2485(left) and 0.2340(right)

Don't hesitate to correct me.
If anyone has these shims available I will buy them asap.


Thanks

Nebulus

iTrader: (14)

I agree that the contact pattern looks pretty good. However, Like Jays SSZ28 said, that grease makes it beyond difficult to see the exact pattern. I agree that you should tighten up the backlash and see how that affects the ride.

I've heard of a goal range as wide at 0.005"-0.015" for backlash, but mostly i see ranges more like 0.007"-0.012"/0.007"-0.015", so i'd suggest (as you're already planning for) around 0.008" For each 0.001", you need to transfer 0.002" in bearing shims from one side to another. To decrease backlash, the carrier needs to move towards the passenger side of the car, therefore, decreasing shim size on the right and increasing on the left. 0.012" down to 0.008" would need 0.008" transferred from right to left. If your originals were 0.2425"/0.2400", your new ones would need to be 0.2505"/0.2320"

Also, take note that backlash should be checked around the entire ring gear, not just one spot, and the backlash should not vary more than 0.002" If it does, check torque on the ring gear bolts.

Gramozeka

I do realize the grease pattern sucks, unfortunately I can not go back at this time and reprint the pattern. The only way to do this is over this weekend this means the flowing weekend is when I will be finishing the car, but I have other commitments. And the whole thing is disassembled in the middle of metropolitan street. I can spend 2 weekend under the car but 3 is a bit too much.

So I am asking all of you to do your best with the pictures I have they are 5mp, from different angles.

Nebulus:

The gears were marked in 3 spots and all patterns looked the same.
I think you shift number are a little too aggressive. Here are the links to websites where I got 1.4-1.5 multiplication factor from

http://www.drivetrain.com/parts_cata...tructions.html
http://www.s10forum.com/zexel_torsen_how_to_install

It seems that your numbers might put me a tad under .006. However I would go for the shims in the range between you and me to have a backlash of .006-.008

All I need now are the shims(and couple more good opinions). Any one has shims leftover?? I need them for this weekend! You don't need them, they are just taking up the space in your garage let me have them :-)

target value for now is 0.2485(left) and 0.2340(right) total .4825

Nebulus

iTrader: (14)

I was going by the GM 4th gen F-body service manual. I was going to say that the difference between our calculations is that your links use different rear end sizes, but the second link references the GM 7.5"/7.625" rears.

Gramozeka

Nebulus:

You have mentioned three different ranges for backlash, what does the factory manual says. It could be that during assembly of new ones the range should be between .006-.010 but what is acceptable wear?

I still am looking for the shims. Does any one have them?

Nebulus

iTrader: (14)

Sorry about the confusion; 0.005"-0.009"

relzbade

did you look at the pinion bearings too? a lot off accel/decel noise comes from those bearings. if you are noticing a noise only on turns it is most likely a front hub, which is most noticeable between 35-50 mph. check the front hubs by raising the front ends and trying to push and pull on the top of the tire while feeling for play, or while driving about 40 mph gently turn the wheel to the left and right, and the noise will increase. if it increases while turning to the left then the noise is coming from the right front hub bearing, and vise versa. if a rear axle bearing is bad it will normally cause the seal to leak and make a squeak or moan once for every two revolutions of the tire.
I have a few shims laying around if you are in the Oklahoma city area.

relzbade

clunk in the driveline is normally u-joints, or slip yoke. carefully pull the caps off the u-joint to see if there is any grease left in them. and pile some bearing grease inside the slip yoke to see if it helps the clunk

relzbade

if you get the preload set and backlash where you want it, and the pattern doesnt look right, then decrease the backlash to min spec. and make sure you roll the bearings over enough to seat them. about 20 times or so then recheck final preload

killagt

iTrader: (3)

Cap ? what cap ? I need to know more about this please, I have a very little clunk when I rotate the DS by hand, can you tell me more about this grease thing pls, im new to this.

relzbade

the drive shaft has u-joints at either end that connect it to the pinion and the slip yoke. you can unbolt the driveshaft from the pinion with a 11mm box end wrench and pull the shaft forward to remove it, but it will probably require a pry bar to remove. then carefully pull the driveshaft out of the trans. if you can pull the caps off the u joint then do so to check for grease. if they are dry then replace them. then move the joint back and forth on both ends to see if they are stiff or squeak. the slip yoke can be greased with wheel bearing grease to help with slack. just a couple finger fulls of grease and work it into the groves. Then work the slip yoke on and off the trans output shaft a couple times and add more grease.