I'm now a member of the G80 "Gov bomb" club! (Lucky me)

TurboMinivan

Still plays with cars
Location
Lehi, UT
Friday was not a happy day for me. Driving home from work in the Corvette, I began to smell hot coolant. Once home in my driveway, I opened the hood and discovered the radiator had ruptured. I guess I shouldn't be too mad since its date code indicates it is the OEM original as installed by Chevrolet back in 1988, but... still. Oh, well.

I had an appointment in Salt Lake, so I switched keys and jumped into Ol' Reliable--the GMT800 2500 8.1L Suburban--and off I went. I got to my engagement just fine, and all seemed well. When it was over and I was back in the 'Burb, I slowly backed out of my parking space (I had to be cautious as I was right alongside a curb). Once I cleared the curb, I cranked the wheel to the right and kept reversing when I suddenly heard multiple metallic clanging noises from the back of the vehicle. "Am I running over a kid's bicycle?" I put it in Drive, cranked the steering to the left, and barely applied the throttle just in case I had actually run over something. Immediately upon moving forward, I heard the left rear tire: chirp-chirp-chirp-chirp. I stopped. "I know that sound. Why is my rear axle locked up?" I actually checked the transfer case buttons, just to verify I hadn't accidentally engaged 4WD. Nope--still in 2WD. So I straightened the wheel, went back to Reverse, and slowly crept backwards until I was sitting (diagonally) in a few parking spots.

Hmm. I decided to see if I could verify my locked diff hypothesis. I dug out the rig's wheel chocks and placed them at one front tire, then used the factory bottle jack and lifted the rear axle from the pumpkin until both rear tires were an inch or so off the ground. Fired the engine, put it in drive, and lifted off the brake just a bit until the tires could slowly turn... and had a passerby verify that both tires were indeed spinning in the same direction. And as a second test, with the engine off I turned one wheel by hand and observed the opposite wheel again turn in the same direction. Hmm. Is my G80 exploding?

Not knowing what else to do, I decided to call @UPNO4 and bounce my symptoms off him. He confirmed my suspicion, and told me "the pin has been pulled from your grenade." Well, great. Now I'm down two cars within a three hour span. <sigh>

I called my bff Mike and had him hop in his own GMT800 2500 Suburban and come rescue me with his trailer. He very kindly dragged me back home, where my rig was unloaded and sits while I devise a repair plan (and come up with the money to implement it).

And that's why I am now daily driving my TJ.


So, what to do about it?

The Suburban is a street-only tow rig for me. It has seen gravel surfaces only a handful of times in my eleven years of ownership, and I cannot recall a single instance where I needed or tried to actually use the rear locker. For those reasons, I'm thinking I'll just replace it with a plain old open diff and get it back on the road.

Is there anything else I ought to be considering?
 

Stephen

Who Dares Wins
Moderator
Friday was not a happy day for me. Driving home from work in the Corvette, I began to smell hot coolant. Once home in my driveway, I opened the hood and discovered the radiator had ruptured. I guess I shouldn't be too mad since its date code indicates it is the OEM original as installed by Chevrolet back in 1988, but... still. Oh, well.

I had an appointment in Salt Lake, so I switched keys and jumped into Ol' Reliable--the GMT800 2500 8.1L Suburban--and off I went. I got to my engagement just fine, and all seemed well. When it was over and I was back in the 'Burb, I slowly backed out of my parking space (I had to be cautious as I was right alongside a curb). Once I cleared the curb, I cranked the wheel to the right and kept reversing when I suddenly heard multiple metallic clanging noises from the back of the vehicle. "Am I running over a kid's bicycle?" I put it in Drive, cranked the steering to the left, and barely applied the throttle just in case I had actually run over something. Immediately upon moving forward, I heard the left rear tire: chirp-chirp-chirp-chirp. I stopped. "I know that sound. Why is my rear axle locked up?" I actually checked the transfer case buttons, just to verify I hadn't accidentally engaged 4WD. Nope--still in 2WD. So I straightened the wheel, went back to Reverse, and slowly crept backwards until I was sitting (diagonally) in a few parking spots.

Hmm. I decided to see if I could verify my locked diff hypothesis. I dug out the rig's wheel chocks and placed them at one front tire, then used the factory bottle jack and lifted the rear axle from the pumpkin until both rear tires were an inch or so off the ground. Fired the engine, put it in drive, and lifted off the brake just a bit until the tires could slowly turn... and had a passerby verify that both tires were indeed spinning in the same direction. And as a second test, with the engine off I turned one wheel by hand and observed the opposite wheel again turn in the same direction. Hmm. Is my G80 exploding?

Not knowing what else to do, I decided to call @UPNO4 and bounce my symptoms off him. He confirmed my suspicion, and told me "the pin has been pulled from your grenade." Well, great. Now I'm down two cars within a three hour span. <sigh>

I called my bff Mike and had him hop in his own GMT800 2500 Suburban and come rescue me with his trailer. He very kindly dragged me back home, where my rig was unloaded and sits while I devise a repair plan (and come up with the money to implement it).

And that's why I am now daily driving my TJ.


So, what to do about it?

The Suburban is a street-only tow rig for me. It has seen gravel surfaces only a handful of times in my eleven years of ownership, and I cannot recall a single instance where I needed or tried to actually use the rear locker. For those reasons, I'm thinking I'll just replace it with a plain old open diff and get it back on the road.

Is there anything else I ought to be considering?
If everything else is good, I'd just swap the diff.
When I saw G80, I immediately thought about Isuzus. The G80 code means factory LSD, which was highly sought after. 😬
 

bryson

RME Resident Ninja
Supporting Member
Location
West Jordan
Other than what @johngottfredson mentioned I don't see an issue with finding an open diff to replace your blowed up gov-lock and just getting it back on the road.
Are you interested in a gear ratio change?
 

spaggyroe

Man Flu Survivor
Location
Lehi
I'm biased and in my world, the ONLY limited slip that exists is the Detroit TrueTrac. If that isn't in the plan, I'd just toss an open diff in it and run it. Just my $.02
 
Seen a lot of blown up 10bolt G80s but had good luck with mine in the 14b (4 years, not a long time). Bummer. I always thought I'd put a locker in the X if the lsd let go, never did. I've had a locker in the F350 and never really used it (granted, it doesn't get used in the dirt/snow/mud/crud like the X did). So I'd either find another G80 GT5 14b and swap it in (dime a dozen?) or just go open.
 
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