Ring, Pinion and AirlockersInstall - Questions

Joined
Mar 26, 2012
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427
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Chicago
Hello Forum,

First, I have read the threads, seen ZUKs site, watched 2 youtube video's numerous times (part 1 and 2 ARB Fj40 Install, Tacoma ring and pinion install professional guy provides tips), bought a diff rebuild book.

I am attempting, 1st time, both front and back 4.88 Sierra Gears with Airlockers. I have a few questions for those that have related experience.

It's my understanding correct about backlash? Backlash is set by moving the ring toward or away from the pinion via the diff adjust nuts. Move the ring towards the pinion the space between the pinion teeth and ring teeth is less therefore the blacklash is less. Move the ring away from the pinion and the backless is more.

Once the backlash is set (further assume the pinion depth is also set and so is the pinion pre-load) would I have to tighten both diff adjust nuts in uniform to further load the carrier bearings or can i just assume no further adjustments to the diff adjust nuts? From what I read, on this forum, the pre-load should go up by 10 ft lbs when the locker/diff is installed and setup correctly.

Pinion depth is set by putting shims under the pinion race. I would rather put shims between the pinion and pinion bearing as I think it is more of a f-ing pain to beat the racer in and out to add and remove shims than to use a puller on the bearing to add shims under the bearing. My experience with this process is once I have to replace the shims they are ruined. There is not enough space on the back of the race to not beat on part of the shims with a drift to pop the racer out. Therefore once I pop the racer out to adjust the shims the shims have dents in them from the drift. Is it OK to reuse the shims or are they garbage now?

I cannot understand my contact pattern. I am not getting a good readable patter/well they don't look as readable as what is see on the youtube videos. What are peoples thoughts on the pattern? I loaded up almost all my shims on this go: 2 - 8mm, 3 - 5mm, 2 - 3 mm. I think the pattern shows the pinion is too shallow however considering all the shims I figured it would be to deep. Shallow, as I interpret it, means the pinion is not close enough to the ring gear and needs more shims. Deep, as I interpret it, means the pinion is over shimmed.

Last 2 piece of information. This is a Fj80 3rd member but I assume this really makes no difference as rear 3rd members on all LC are interchangeable. right? The front pinion bearing I am not installing while I try to set up the blacklash and pinion depth. The reason for this is, its a pain to press on and off the front bearing while I try to get this all setup. I just keep the 3rd member in a fixture, ass end down, and put the flange on with the flange nut. However maybe this is a bad idea and part of the reason why I don't get a great contact pattern because the pinion would be more stable with both bearings seated. Thoughts?

Attached is was most recent pattern. "First" means it was the first turn, back and forward. "Second" I added more gear paint back and did a second turn, back and forward.

Backlash Check: - looks right to me at .006

cost - first turn.jpg


cost - second turn.jpg


drive - first turn.jpg


drive - second turn.jpg
 

Steamer

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Jul 20, 2009
Messages
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Miami, FL
I've never done a gear install but hope to some day hence my watching this thread, other threads & videos, and waiting for replies.

The front pinion bearing I am not installing while I try to set up the blacklash and pinion depth. The reason for this is, its a pain to press on and off the front bearing while I try to get this all setup. I just keep the 3rd member in a fixture, ass end down, and put the flange on with the flange nut.
But while waiting, I don't understand what you mean by pressing "on and off the front pinion bearing". I've changed my front bearing a few times and I just slid off the old and slid on the new. I didn't know it was a press fit. Maybe my pinion is worn?

Also I don't see how you can rotate the pinion properly for a pattern check without the bearing being in there.

Sure hope someone chimes in.
 

RustyNailJustin

 
 
 
Joined
Dec 26, 2002
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Western CO and Southern Oregon
Use something to thin your marking compound. I normally thin with a little bit of kroil.

What do you currently have under the front race? An educated guess for good starting point on a Sierra gear set and 4.88s is .030.

You need to replace the shims Everytime you pound them out. Like you said they get messed up when you remove the race.

Use a large brass drift or deadblow to remove the pinion from the housing. No need to press it in and out.

Be sure you are completely setup before taking a pattern. Put it together like you are done minus a solid pinion spacer or crush sleeve, or locktiting anything.
 
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Joined
Mar 26, 2012
Messages
427
Location
Chicago
I've never done a gear install but hope to some day hence my watching this thread, other threads & videos, and waiting for replies.



But while waiting, I don't understand what you mean by pressing "on and off the front pinion bearing". I've changed my front bearing a few times and I just slid off the old and slid on the new. I didn't know it was a press fit. Maybe my pinion is worn?

Also I don't see how you can rotate the pinion properly for a pattern check without the bearing being in there.

Sure hope someone chimes in.
All the videos I have seen have the front bearing fall right off. I hav a new pinions and bearing and the bearing has to be pressed on. Maybe I’ll cruiser outfitters about this issue as I got the Serra grears and rebuild kit from them
 
Joined
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The big bearing closest to the pinion head is absolutely a pressed onto pinion fit.
The smaller bearing is not, it's a machine fit, you can't slide it on by hand, takes a tap with drift or deadblow
Yes I know the lager bearing has to be pressed on. I’ll try to pound the smaller bearing on with drift and dead blow
 
Joined
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Messages
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I think the pattern shows up better now with both pinion bearings in place. I was able to beat the smaller pinion bearing into place with a dead blow hammer.

The gear compound that comes with Serra Gear install kit is so thick RustyNailJustin made a good suggestion to thin it out. However I was in a rush and had no thinner so I assumed i can just look at the pattern where the pinion gear marks the ring gear with compound (all the videos I saw had you look where the compound is removed), is that OK to use for pattern definition?

I used a .003, .005 and .008 all solo in 3 try's and I think that I am still way to shallow. Here are my pics of drive and cost. Does it look to shallow?

The pattern seems to be acceptable IF I get both drive & cost more centered between FACE and FLANK. As according to my Serra Gear pattern identification I interpret my pattern in the images to look like the pattern circled in red just to shallow.

Thoughts? Does anyone agree or disagree with what I have stated and interpreted my pattern to be?

Also where is a good place to buy more pinion shims? Any recommendations?

.08 coast.jpg


.08 drive.jpg


acceptable pattern.png
 
Joined
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Messages
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Way to shallow, post a pick if the teeth you painted.

Try .030 under the race.

Call west coast differentials for a shim stack pack.
Crap, I just realize I looked at your suggestion earlier for .03 and read it as .003.

Will post pics of the paint in about 2 hours
 
Joined
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Messages
427
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Way to shallow, post a pick if the teeth you painted.

Try .030 under the race.

Call west coast differentials for a shim stack pack.
here are the pics of the painted teeth. You cannot tell where the teeth meshed or at least I cannot

painted teeth 1.jpg


painted teeth 2.jpg
 

Steamer

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I can't advise but wanted to ask, are you holding back tension on the ring gear while you turn the pinion?
 
Joined
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Messages
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I can't advise but wanted to ask, are you holding back tension on the ring gear while you turn the pinion?
Yea, just pressing my palm into the side of the ring while I turn the pinion. I saw that reccomendation in a video.
 
Joined
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Messages
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I tried .033 under the race and I assume it is still too low. See pics. Drive looks like it is centered but too high on the teeth. Cost looks too high and at the heal.

The original setup from OEM came with 4.11 gears. The shim between the bearing and pinion gear is 1.3 mm. Much thicker then all the shims that came with my kit. Maybe that makes no difference as the ratio is different
.033 coast.jpg
.033 drive.jpg
 
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Joined
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Messages
427
Location
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Hello yall

Back at it. So I just did .048 and then .062. I think that I am still too dam shallow....See pics. First set .048 and second .062. The drive still does not show up as well as the coast.

This AC Delco marking compound is much better than what comes with the gear kit. It is not as thick.

For the cost pattern on .062 is still looks like half the pattern is off the ring. So if half is off should I not double the shims?

Coast .048.jpg

cost .048

Drive .048.jpg

Drive .048


Cost .062.jpg

Coast .062

Drive .062.jpg

Drive .062
 
Joined
Oct 18, 2007
Messages
247
Location
Chandler AZ
Hi csd-
I see conflicting things going on there......you have a front 9.5"....you said it was an 89 FJ62 3rd......Sierra Gears which are good gears.....you should see a good pattern with .055~.060".

First, get about 10~20 INCH/POUNDS on the pinion preload alone.....then install the main center carrier and crank some Carrier Bearing PreLoad CBPL in there and adjust your backlash to the same .006" you originally used.

You don't really have to measure the total preload but you need need some "tightness" on the carrier bearings for the paint test. After your wheel adjusters are set to your satisfaction then tap on the sides of the bearing caps to "equalize" the tensions on both carrier bearings and then verify your backlash again to make sure it has not changed drastically.

Here's the simple way to get a good readable pattern......paint 3 teeth....then hold pinion flange with a rag to offer some resistance....then turn the ring gear with a 19mm wrench. Wipe it back and forth 3 or 4 times holding plenty of tension on the rag. You will get the best possible wipe and pattern presentation that way.

I think Sierra gears like 007 backlash minimum....it's scribed on the ring gear.


Ken
 
Joined
Oct 18, 2007
Messages
247
Location
Chandler AZ
I see scrape marks on your ring gear.....don't wedge screwdrivers or wrenches up against the ring in an attempt to "offer resistance" for a pattern check. If your carrier bearings don't have strong preloads then the ring gear will deflect and screw up your painted pattern look. I think that is why your patterns are all over the board.

Use the "Rag on flange" method.
 
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