04 Silverado G80. Clanks into action, stumbles/vib

[TexasTea]

Hi all,

I have a 2004 Silverado with around 170,000 miles on it, OEM all components original even the G80 Locker.

The fluid in the diff was changed about 15,000 miles ago with 75w90 semi-syn supertech GL5. Just that fluid and no additive was added since the manual stated specifically not the add any LSD additives.

The issue is that ever since I've had the thing, since 60,000 miles, the rare occasions when the g80 locks, i can feel it clank/bang into locked mode but then the wheels seem to start to stutter/drag/vibrate... mind you the vehicle is not even stuck were now driving down the road and it does not feel normal. i have to come to a complete stop then the vehicle starts driving normally again

Because i live in the city and it never sees locking use (maybe 5 times max, unprovoked) i dont know why this is happening. I have been thus far afraid to provoke it into a lock because i dont want to blow anything up should this thing be on its way out.

I am basically posting to see if this sounds normal or not,

When I get the chance I plan on jacking the truck up and having a buddy help me opposite each rear wheel and rotate the wheels opposite each other to test the lock/unlock of the locker which i feel might be as gentle of a real test as possible to not over strain things should this locker be bad, testing it with wheels on the ground and in motion might be too much and cause it to splode.

Just looking for thoughts and opinions.

 

[nascarnation]

Here's how the Eaton G80 works, it needs differential speed between the two sides to engage.

https://www.youtube.com/watch?v=KbMZ9vcYVSg

When you have it jacked up, the wheels will rotate independently, it's not like a clutch type locker.

As for advice on why you are getting that odd feeling, I can't really help out. You might remove the diff cover and inspect the parts.

 

[Lyman]

Sounds pretty normal for a locker to me. They make noise and will cause your tires to scrub once in awhile.

 

[DoubleWasp]

Sounds like at least half of my G80's. They're not exactly civilized. Just more civilized than most lockers out there.

 

[hansj3]

I wish my g80 would clang. Mine has been warn out for at least 100k

 

[caravanmike]

I thought minimum speed to unlock was 35mph. Mine scrubs after locking until I get up to speed.

 

[George7941]

I can feel my G80 lock up but it does not clang and the wheels don't vibrate or drag in locked mode.

With the icy roads we have now, my G80 has been engaging more than usual.

 

[TexasTea]

Originally Posted By: caravanmike
I thought minimum speed to unlock was 35mph. Mine scrubs after locking until I get up to speed.


it very well could be doing this, i dont make a habit to speed up after it locks because im afraid of making it worse. now that you mention it though, its probably working as designed.

 

[meborder]

There are those on this forum who will not agree, but some Limited Slip friction modifier may actually help.

The dirty little secret about the G80 is that, while it is a locking type differential, it also has clutch packs. The shuttering you feel may be the clutch plates in a stick-slip condition while the governor has the unit locked. A FM might help.

Wont do much for the clunk when it engages, but it might lessen the shock to the axle a bit when that wheel tries to grab and smooth out as it tries to accommodate any difference in rotational speed of the two drive wheels.

Regardless, the worst it can do is nothing.

 

[LeakySeals]

I have a towing button on my shifter that changes the way the truck shifts. the truck also has a strange clunk when accelerating, like somethings kicking in about 30mph. Wonder if I have that locker.