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Gear Pattern Checks

pierce88K5

pierce88K5

1/2 ton status
Joined
Jan 11, 2005
Posts
134
Reaction score
2
Location
Alexandria, VA
Need some help reading gear patterns for my 4.56 ring gear on my 14 BFF. I did a complete overhaul and replaced the G80 carrier and installed an open differential with a Grizzly Locker. Currently the shim pack I have installed is .013 on the pinion and the B/L is set to .006. At about 50 mph I have a slight vibration and a grumbling noise when I let off the gas. I believe the pinion my still be too close and I am thinking of installing the .017 shim and see what I get for a pattern check. The posted pics is what I have right now before I change anything to get your guys opinions.
drive.jpg
drive.jpg


drive.jpg

coast.jpg
 
i am no gear man. but what i have seen you are to far to the back of the ring gear and to far to the edge of the teeth on the gear. you need more work if you ask me.

what i have seen is 2/3 contact centered in the tooth area. you are not there.
 
Pattern looks good, is this the only thing that has changed since you messed with gears?

Remember that with deeper gears your driveshaft etc. will be spinning faster, what trans/t-case are you running?
 
Chris,
How do you set the starting shim pack? I have the old pinion markings in the first picture with a GM serial number and the number 11 stamped on it with a .018 shim.

The new pinion from Yukon Gears has the attached numbers etched on it with the number 1 stamped on it. The install instructions from 4x4 Pirate talks about using a chart and compare the old pinion number to the new pinion number and making the changes to the old shim for a starter shim pack. The problem is that there is not an 11 on the chart. Any ideas? - Wes

old pinion.jpg

new pinion.jpg
 
pierce88K5 said:
Chris,
How do you set the starting shim pack? I have the old pinion markings in the first picture with a GM serial number and the number 11 stamped on it with a .018 shim.
Click to expand...


AFAIK the OEM numbers don't help you any with aftermarket gears, I'd bet that number is related to something else.
 
Sweetk30 mentioned that it looked to him that the pinion was only making 2/3 contact on the ring gear. Do you think that I need to move the pinion closer to the ring gear? - Wes
 
Looks like I will move the pinion in closer and see where that gets me. I will post some pics when I am done. - Wes
 
DEMON44 said:
that pattern is too high, needs to be deeper no doubt.
Click to expand...

I fully disagree, the shape of the pattern is money.

I understand why you would think the patten is, on the whole, too high up on the tooth but its the shape that matters. Setting up gears doesn't really work like that, a deeper pinion will change the pattern.
 
heres from the trade school days.

You want 50/50 over the face flank line. 60-70% on the toe and 30-40% on the heel. to allow for wiping action under load.


Gear%20set%20diagram.jpg
 
And by the same right, I've seen people try to fix a pattern like that and end up with noisy gears.

Just my experience, I don't do this professionally but I've done 25-30 sets.
 
I decreased the pinion shim to .010. Here are the results. Looks like it is closer to the center of the gear, but B/L is now .004. Still within specs, but on the low side. - Wes

010 shim.jpg

010 shim2.jpg
 
are you making a lot of resistance on the pinion when you turn the ring gear over?
 
Zim,
Yes. I have the axleshafts installed and set the emergency brake to cause some drag while I turn the pinion. - Wes
 
Luke,
Haven't tried it yet. Waiting on some feedback. I agree it looks better. Would you be concerned about the .004 B/L? - Wes
 
Chris,
Thanks for you help. I really appreciate your input and don't want to start a tech war here. No where else can I go to get good advice on working on a K5 than here! Keep charging and I will let you know how the vibration check goes later. - Wes
 
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