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My 2005 Yukon XL

Breakthrough.

A friend has an 05 Silverado 1500 plow truck that has a snapped rear frame section. Took a preliminary look tonight and it has a GU6 RPO code. Agreed on $150 if the unit is good. The truck is caving in so we are gonna flop it on its side for removal in the next week or so.
there you go! hope it all works out. that would be a good deal. keep as many bolts as you can when removing that donor unit.
 
search up some youtube on what it takes to dismantle one of these units. maybe they are not so bad. worst case is once you get the unit apart you just need to have a bearing or two pressed out and back in.

the only thing you'll need if you decide to pull it and want to continue driving it while it's out is get you a couple of junk CV shafts and pull the hub ends off the shaft and bolt them into your spindles so the hubs don't fall apart on you.
It's definitely an option but I am guessing the oil is going to be super metallic from the failure. Won't know till it's out and apart.

You are correct, there are some great rebuilds on the YouTube. I think I may be doing cv shaft seals too before the replacement goes in.
 
Not the most fun project, but it's out. Of course winter decided to come back just in time for this.
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Of course had to remove the pitman arm, again. Totally roasted the rubber on it. Also had to remove the drivers tie rod.

Wonder what the nomenclature is on the wobbly output.
 
My guess would be if the pumpkin or housing that holds the ring gear is held in place by those bearings, the bearings getting sloppy caused it. Does the race look like it spun in the housing or is it just a loose fit? I have seen loose fit races in aluminum housings before and was just the way they were built. If there are galding marks in the bore where the race goes, that’s a dead giveaway.

If not, and you need to get it back together, take a center punch to the housing and knock a new race in there. Gently file the edges on the ring gear or us a drimmel tool on them only on the edges not the gear face.

Fill with a heavier oil like a synthetic 85-140 or use the regular oil with a quart of slick 50. I had an old ford pickup that had the manual granny 4 speed with warn gears. Dumped a bottle of slick 50 in it and that did wonders! It will last You a while until you source a good unit and have the time to go through that unit with all new bearings and seals.
 
My guess would be if the pumpkin or housing that holds the ring gear is held in place by those bearings, the bearings getting sloppy caused it. Does the race look like it spun in the housing or is it just a loose fit? I have seen loose fit races in aluminum housings before and was just the way they were built. If there are galding marks in the bore where the race goes, that’s a dead giveaway.

If not, and you need to get it back together, take a center punch to the housing and knock a new race in there. Gently file the edges on the ring gear or us a drimmel tool on them only on the edges not the gear face.

Fill with a heavier oil like a synthetic 85-140 or use the regular oil with a quart of slick 50. I had an old ford pickup that had the manual granny 4 speed with warn gears. Dumped a bottle of slick 50 in it and that did wonders! It will last You a while until you source a good unit and have the time to go through that unit with all new bearings and seals.
I don't think the races spun in there but will have to take a closer look.

I'm still waiting to get the plow truck flopped for inspection and removal of the other unit. Really thinking about tear down for inspection, and resealing the replacement unit at a minimum. I will have a hard time using any parts from mine without a complete clean out and rebuild. The amount of glitter on everything inside is the most I have ever seen.
 
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Got the parts truck flopped tonight. It's a rot box for sure. I will be back Friday to inspect the differential better and hopefully remove. It has a skid plate under the diff, mine didn't.

Part of me is thinking about the 4l60e for a shelf core unit. Maybe the airbag sensors is they cross reference and aren't buldged. Not much h worth anything on this truck besides the engine and converters. It does have a nice original y-pipe.

I ordered a TTX pitman arm, CV axle seals, and a pinion seal for the new unit from RA. Should be here Friday.
 
It's base model, so cloth bench type. Back window has been blow out for a year or so. Critter and weather infiltration.

Apparently their plan was to rally it in the backwoods but the rear frame snapped so quick it never happened.
 
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Got the secondary differential out. It was rough, that truck is nothing but junk. Completely rotted frame. Needed a map gas for nearly every bolt. Pounded several sockets on, etc. Some of the aluminum case is even disintegrating.
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Fluid is black, but not metallic. Some sludge on the magnetic.
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It's definitely got some sludge inside. It also may have had water intrusion? Not sure what the orange looking color is.
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Breaings look much better. It did have some stub shaft play in the drivers side. More than I would have thought, but way less than mine. I notice today that my pinion is damn near sharp on the edges, where this one is smooth and the patter looks very nice on drive and coast sides. I really wish this unit was in better shape on the exterior. It really needs new bushings as well as my passenger shaft extension as the aluminum is disintegrated badly.
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I have yet to find a quality replacement wither on FB Marketplace. All wrong gear codes.
 
How are the ring and pinion setup on these units? like on the rear units the pinion housing is shimmed along with the carrier has threaded rings with locking pins to set the lash and mesh. I'm sure you can easily set that all back up after doing a housing swap.
 
Can you use the housing on yours? take the two and make one good unit? if not, now that you have a unit with good ring and pinion, if you find another unit, doesn't matter what the gear ratio is, you can swap the innards.
I could, but we would need to setup the gears. I don't have experience with that, would love to learn. Really thinking about running this units main case, with my pinion yoke, my stub shafts, my passenger axle tube extension, and my press in isolators. I'm getting crazy pressed for time, with the trip and weather not cooperating, but this is still an option.

Basically this unit is in poor condition on the exterior, but decent interior where mine is opposite.
How are the ring and pinion setup on these units? like on the rear units the pinion housing is shimmed along with the carrier has threaded rings with locking pins to set the lash and mesh. I'm sure you can easily set that all back up after doing a housing swap.
So ring and pinion setup is just like a rear axle. You set that to a specific, then work on the ring gear. The side inner bearings are adjustable. You screw them in and out to achieve ring gear mesh to the pinion. Then lock them in after running a mesh compound. It's kinda a pain from what I gather, but normal for gear setup.

Tomorrow I am going to get a few things at the auto store. Sunday we will clean everything up and determine how we are gonna put this back together.
 
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