2015 Front Differential Fluid = Black

Mardimus · March 11, 2020

So I dove into the project this weekend. Dropped the front differential in about 2 hours. Over the last few days I got the case apart and started taking things apart to inspect them. Found some bearings that were pretty damaged but overall everything looks pretty good (pics). Maybe some scoring on the shaft where the bearings were but not sure its an issue yet. Let me know what you think (pic 3 & 4).

My only issue now, is that I cannot remove the inner output shaft (pics 2 and 5). The bearings and race are on there and I cannot part them. I tried a brass punch to start, then moved on to a gear puller to push it out. All with no luck. Any thoughts on how to remove it? Thanks for the help.

Edited March 11, 2020 by Mardimus

davester · March 11, 2020

Given how chewed up the shaft on the carrier, I would be looking for a cheap diff from someone parting out a truck, or somewhere like that, with the right ratio that you can just bolt in... Looks like you need a new carrier, and the metal bits will have trashed all the bearings, and possibly the ring&pinion gears.

You can rebuild it, but it'll probably be in the same price range as a used diff.

Mardimus · March 11, 2020

18 minutes ago, davester said:

Given how chewed up the shaft on the carrier, I would be looking for a cheap diff from someone parting out a truck, or somewhere like that, with the right ratio that you can just bolt in... Looks like you need a new carrier, and the metal bits will have trashed all the bearings, and possibly the ring&pinion gears.

You can rebuild it, but it'll probably be in the same price range as a used diff.

I’m going to take it into Yukon Gear and see what they think about the parts but so far only that shaft and the bearing are the issue. Everything else looks great. The bearing only had a small amount of pieces that came out. Looks more crushed than anything. I have had zero luck since my first post in finding a used one and rebuilt ones were spendy. I think the kit from Yukon gear is like $200-300. Depending on what I need. I’ll plan to rebuild and if all else fails then go with a rebuilt from Yukon Gear. Still can’t figure out how to separate the inner output shaft and differential assembly.

davester · March 11, 2020

I would suggest at least replacing all the bearings in the diff. There will have been fine metal bits carried in the fluid, and passed throughout the diff. You may be able to get the bearings cheaper (but same or better quality) directly from a bearing supplier using the numbers on the various bearings.

Mardimus · March 11, 2020

2 minutes ago, davester said:

I would suggest at least replacing all the bearings in the diff. There will have been fine metal bits carried in the fluid, and passed throughout the diff. You may be able to get the bearings cheaper (but same or better quality) directly from a bearing supplier using the numbers on the various bearings.

Great idea. Thanks for the tip.

Mardimus · March 14, 2020

On 3/10/2020 at 6:12 PM, davester said:

Given how chewed up the shaft on the carrier, I would be looking for a cheap diff from someone parting out a truck, or somewhere like that, with the right ratio that you can just bolt in... Looks like you need a new carrier, and the metal bits will have trashed all the bearings, and possibly the ring&pinion gears.

You can rebuild it, but it'll probably be in the same price range as a used diff.

Edited March 14, 2020 by Mardimus
double post

Mardimus · March 14, 2020

Finally got the inner output axle shaft off.
Used a 20 ton shop press. Slid right out. Looks like the two major areas are the differential case and the axle shaft has some gouging. Any thoughts on a good place to buy these two parts? Will bring them into Yukon Gear on Monday to see what they say about the rebuild.

Mardimus · March 22, 2020

Ended up buying a new differential case from Yukon Gear, a Master Rebuild Kit and a bearing adjuster with lock ring (Pics).

At the moment I have the new ring bearings pressed on the new carrier case and I am in the processes of installing the side bearing adjusters and races.Does anyone have any recommendations or can send me the step by step procedures from a shop manual for my differential? The only issue I am having now is getting the correct way to install them and get them set. Thanks for the help.

Edited March 22, 2020 by Mardimus
typo

davester · March 22, 2020

Perhaps sign up to the full-service manual at a site like alldatadiy.com? The FSM for my truck has it, and it's a fairly involved process with a bunch of specialized tools.

Mardimus · March 22, 2020

1 hour ago, davester said:

Perhaps sign up to the full-service manual at a site like alldatadiy.com? The FSM for my truck has it, and it's a fairly involved process with a bunch of specialized tools.

Thank you so much, I am checking it out right now. I get the theory and taking my time, I just want to make sure I get the preload and back lash perfect. Really want to make sure I do this right. It has been fun learning how to do it. Thanks again.

Snowcamo · March 23, 2020

On 3/22/2020 at 2:41 PM, davester said:

Perhaps sign up to the full-service manual at a site like alldatadiy.com? The FSM for my truck has it, and it's a fairly involved process with a bunch of specialized tools.

X2 29.99 for a year and if you redo the subscription its less per yr.

Mardimus · March 26, 2020

On 3/23/2020 at 2:12 PM, Snowcamo said:

X2 29.99 for a year and if you redo the subscription its less per yr.

On 3/22/2020 at 12:41 PM, davester said:

Perhaps sign up to the full-service manual at a site like alldatadiy.com? The FSM for my truck has it, and it's a fairly involved process with a bunch of specialized tools.

I ended up with the AllDATAdiy and it was pretty limited for my 2015 in terms of front diff. Gave pricing and parts with some exploded views but nothing too detailed. For my 2009 Yukon XL it was extensive so that is good.

Mardimus · March 26, 2020

So today I started divining into the bearing adjuster install and found some helpful info on another forum.

"Take your carrier bearing adjusters and install the roller bearings in both. Install new lock tabs, using a dab of grease to hold them in place, then drive the adjusters into place in both case halves. Set your distance on the adjusters back to about what they where when you removed them, this will just give you a starting point for setup".

My issue here is sort of two part.

one of the adjusters was pretty bad and had to be tossed, the second adjuster I had to unscrew to clean, not realizing I needed to gauge the gap. So no luck there. But I think I can full screw then together and then unscrew a bit and install. Then adjust once I get the carrier case in. So I am not too worried about this portion as I will have to make adjustments anyway.
This part is strange. So when I disassembled the diff, I had no locking tabs on either side. The right side, long axle shaft side, i figured the lock tab was destroyed due to that side bearing failing. However, the opposite side did not have one either. So I decided I would head to the dealer to see what their thoughts were. They pulled up the drawing and showed that I do not have those in my 2015 GMC sierra Denali 1500 8.25/3.42 front diff. So they stated I did not need them. Yet when I look in the case I can see where both of the lock tabs would go. So now I am confused.

Does anyone have any thoughts on my confusion with the lock tabs? I know I may be overthinking all of this but I really want to get this right and I have a lot of time on my hand and the truck is not critical at the moment. Nice and slow to get it right.

Pics below:

Edited March 26, 2020 by Mardimus
Pics

davester · March 26, 2020

Sorry that it's not in the FSM for your truck. Don't know why it's like that (available for some but not others), maybe it's based on who makes it?

I don't know how all those bits go together (I've just replaced the bearings/bushings at each end of the front diff of my truck and changed the fluid.

Does it appear the parts are at all similar to the diff diagrams in the '09 Yukon FSM?

Or maybe contact alldatadiy to see if they have that info available (perhaps sold separately?) or where you might find it.

Or maybe see if you can figure out how who made your front diff and the model of it and contact the manufacturer for where to find that info?

It has to be available somewhere, as it's readily available to mechanics (otherwise, it's just replace the whole thing and parts wouldn't be sold for it).

Mardimus · March 27, 2020

21 hours ago, davester said:

Sorry that it's not in the FSM for your truck. Don't know why it's like that (available for some but not others), maybe it's based on who makes it?

I don't know how all those bits go together (I've just replaced the bearings/bushings at each end of the front diff of my truck and changed the fluid.

Does it appear the parts are at all similar to the diff diagrams in the '09 Yukon FSM?

Or maybe contact alldatadiy to see if they have that info available (perhaps sold separately?) or where you might find it.

Or maybe see if you can figure out how who made your front diff and the model of it and contact the manufacturer for where to find that info?

It has to be available somewhere, as it's readily available to mechanics (otherwise, it's just replace the whole thing and parts wouldn't be sold for it).

I agree with young appreciate all the help. I know its out there and it doesn't help this is my first diff rebuild. Like I stated earlier, it has been fun learning and researching and I have extra time on my hands so I am in no rush. Ill do some more digging. Might make a few calls too.

I have been referencing these two web pages/forums for info as they are similar in my endeavors.

Truck mod Central -Rebuilding GM 8.25 IFS

TahoeYukonForum - 8.25 Front Diff Rebuild

Both have been great sites, the Yukon link is an 05 Yukon and the Truck Mod link is for pre 2011 given that he posted it in 2011.

Edited March 27, 2020 by Mardimus