Yet ANOTHER gear pattern thread

[Recon 78]

Posted a thread a few days ago about my detroit/grizzly unlocking under coast going straight

Ruling out thrust angle, within 1/4 degree
Last 2 things in detroit troubleshooting guide are improper gear setup and bent axle.

Did some gear compound testing today, pics attached. Looks ok but any feedback welcome. Pinion depth? Just looking for any ideas on what to look for

.006/.007 backlash

 

[76zimmer]

Check the Dana gear pattern chart, but it looks pretty good to me.

 

[Jimmy85]

Your pattern looks good. But in the second pic the contact looks too deep. I would reduce the pinion shim say .003. Not saying that is the culprit though.

 

[Recon 78]

Thanks, was wondering about the depth.
Looks good but wonder if the detroit likes a certain value to play nice

 

[Blue85]

Really? Changing the pinion depth .003" has a noticeable effect on how the locker unlocks? Are there some references for that?

 

[Recon 78]

Since the locker seems to be unhappy under coast I'm gonna try to get the coast pattern off the toe
Pulling pinion tonite to see if I can read it's paterrn

 

[Blue85]

Heel-Toe Contact Pattern: The contact pattern on the drive side (convex) of the tooth is mostly towards the heel. The contact pattern on the coast side (concave) of the tooth is mostly towards the toe

Correction: Move the pinion gear away from the ring gear.

I'm just not understanding the physics of how it affects the lock/unlock ratcheting of the NoSpin.

 

[Recon 78]

I'm not sure of it does but am trying to figure out what is affecting the no spin ,so adjusting this will help me rule it out.
Improper gear setup is on the no spin instructions troubleshooting guide as something that will effect its operation

 

[nvrenuf]

I’d got back to the tires before changing the gear set up.

 

[Recon 78]

I've checked air pressure and circumference
Both same
Rotated to diff tires, same
Was thinking of pulling axleshafts to check straightness
Any more ideas welcome, I'm running out of things 2 check

 

[Recon 78]

After thinking about, an easier way to adjust would be to add some backlash.

I can almost double it and still be in spec.
Just trying to affect a change. If none, gears ruled out.

If there's a change maybe it will shed some light

 

[blazinzuk]

That pattern for all intents and purposes is perfectly fine. When they say improper gear setup they are talking seriously improper. Your backlash adjustment will not help at all.
Now there can be other problems in a gear setup. Run the pattern in 4 spaces on the ring gear see if there is any change.
For that matter pull the pinion gear see what the paint looks like on the pinion gear
Is it still a crush sleeve? What’s your pinion bearing preload? Do you have any carrier bearing preload.
If it is a gear issue. It’s substantially more likely that it’s a carrier bearing or pinion bearing issue

 

[Recon 78]

Thanks for the ideas

Crush sleeve eliminator, 25 in lb pinion bearing preload, carrier bearing preload set per 14 bolt Bible.

This was all done on initial build.
I will check more places on ring gear, and runout also.

 

[nvrenuf]

Just to cover all the bases....

Is there any chance that what you are hearing is a driveshaft vibration? I've had vibrations in the past that presented a loud growling that sounded similar to a Detroit ratcheting and it only happened when coasting.

 

[Recon 78]

I guess there is, but I feel no vibration.
The videos have the sound I'm hearing.
I checked my angles on t case and diff
Less than a degree of difference

But my operating angle is 15 deg.
1410 yokes on both

 

[88Silverado]

I couldn't hear anything in the video... To unlock a typical detroit-type locker takes quite a bit of differential torque between the two axles to force separation, like making a turn. Coasting in a straight line should not unlock it. When it engages you will normally hear a slight bang. Now, since you are running such big tires there could be more offset in the tire rotation/diameter compared to smaller tires but you measured the diameters and verified same pressures. I would be surprised if you could hear the locker engage over the tire noise myself.

BTW, the pattern looks fine.
Good luck!

 

[Recon 78]

Thank you, I'm open to any help.
On 1 vid, the sound happens as I pass the your speed sign.
In the other it's rite near the beginning
Hard to capture solo filming

 

[nvrenuf]

I guess there is, but I feel no vibration.
The videos have the sound I'm hearing.
I checked my angles on t case and diff
Less than a degree of difference

But my operating angle is 15 deg.
1410 yokes on both

Your driveshaft sounds kind of similar to mine, mine sounded more harsh and metallic (no top or interior to insulate sound either). It's been a while but I think my shaft is at about a 15 degree operating angle with 1410's and 35" long. With single joints at each end it had a strong a vibration that I wasn't able to shim away, I had to go to a CV to fix it.

 

[Recon 78]

If I don't find anything that's directly affecting the detroit, I may have to put in a mini spool to rule it out.
It would give me the chance to see what's going on without the unlocking, which is definitely happening

 

[Recon 78]

Or maybe drive on the front axle, my 205 is twin sticker would be easy