83" pickup. Finally got the rear end put back together. Replaced the old factory unit with a 58.5" wide unit - Brand new Yukon chromoly shafts, brand new Yukon auto locker, brand new Motive gear 4-88 ring and pinion. Basically did a full overhaul of the third-member including new hardware, crush sleeve etc etc. Recorded backlash at around .007 in multiple positions with what I would describe as a "decent" but not perfect meshing pattern (also not horrible by any measure). Pinion preload landed somewhere around 12 in/lbs if my memory serves me. Following that I staked the pinion nut and called it a day.

Finally get the Chevy 63's burned in and installed, slap the fresh axle under the truck and pull it out of the driveway and by the time I hit the asphalt I hear a noticeable slam. Concerning but not loud or sustained enough for me to shut the truck down. I drive it up and down the street a few times....no noticeable humming or whining coming from the rear end. Accelerates well, no vibration, drives fine. Except when I go from drive to coast and the "SLAM" occurs again.
Get it back to the house and immediately put hands on the driveline.....sloppy. Mark it on end of the extreme and twist/mark it where it stops....measures around 5/8" of driveline play. Obviously an issue

All that suffice to say im at a total loss where I would've went wrong. Did the pinion get pushed away from the ring? Or vice versa? Of course, I won't know exactly where the issue is until I crack it open but I'm wondering if there's somewhere on the 3rd I need to look first? It's not a solid pinion sleeve. I know my lash was tight when I dropped it into the housing. All I can think is that the carrier bearing "nuts" (large rings with many holes) or whatever they're called got pushed outwards? I know their keeper tabs were installed, ring bolts and caps are torqued and loc-tited etc etc. Maybe the crush sleeve....crushed? But why so soon/immedaite?

The truck needs to sit for a bit while I tend to other projects but its going to fester in my mind in the meantime..

Anyone got any ideas?

 

Gotta have a light touch and may have to remove the driveshaft from the diff flange to really feel and determine how much of your slop is actually ring/pinion backlash.
Many locking carriers exhibit substantial slop between drive and coast. Doesn't necessarily mean there is anything wrong.
5/8" driveline total slop doesn't sound outrageous.
You may well discover that actual ring and pinion backlash is just a small bit in the middle of that total slop.
Sounds like you did everything right.

 

Hey mill, thanks for the reply. My first assumption was that the pinion shifted. So I did pull the driveline to see if there was any axial movement when pushing/pulling on the pinion flange. Nada. Its as tight as it was when I staked the nut. But the 5/8" slop is definitely still there driveline attached or not...

 

I never suggested that the slop would change with the driveline off.
With the driveline off, you can gently turn the diff flange ever so slightly back and forth in order to feel the actual ring and pinion backlash in the middle of whatever larger slop there is.
It takes a little finesse to feel just that.
I'm still thinking that your setup is likely OK.

 

Well I got home from work today to take it around the block a few more times. Added maybe 2-3 miles on the ODO overall. 2WD, 4WD high and low....what began as 5/8" of slop is now 1.5". So, its growing....and i've yet to hear any ratcheting via sharp turn or otherwise. Only on coast>accel/accel>coast.

When I apply a light twist to the pinion flange I do believe I can feel the actual differential backlash and it feels minimal. So im 'mostly' convinced that the chunk of it lives in the grizzly. But as for why its growing...i have no clue.

Anybody else who wants to talk me off the ledge, please do. Regardless, I think I need to call up the folks at Yukon and verify this is perfectly acceptable

 

The first time I felt what I thought was a ton of backlash ended up being worn side gear washers. The R&P backlash was spot on. So I have to wonder if there's an issue with the side gear equivalent in your locker. Or the axle splines don't match the splines in the locker. Like millball said, it sounds like you set it up correctly.
Good luck with it and please follow up when you figure it out.

 

Called Marlin Crawler this afternoon. They seemed perfectly happy to hear out my situation. It was the opinion of both the rep who picked up the phone and also another individual at MC that my described symptoms were basically "grizzly locker doing grizzly locker things". AKA par for the course.

On the other hand, I tried to get ahold of anyone at Yukon tech support and sat on the phone collectively for 1.5hrs before finally giving up (2 45 min long hold sessions). Tried to leave a call-back voicemail but the inbox is full.

I may try Yukon tech support again later this week but I'm not holding my breath.

 

Any follow up on this???
Have you tested the locker under actual wheeling conditions??

 

No update other than I'm sure I correctly rebuilt the third-member and the Grizzly is just sloppy. Not bothering with Yukon tech support. Wasted enough of my life on hold with them.

I have wheeled it a bit. No issues on that end. Hooks up well when it needs to. But still clunks on transition from accel to decel and vise versa. I suppose I just got a loose(r) kit than usual?

Nonetheless, not impressed. Will go selectable asap.