Possible front diff failure?

[Discodisco]

Picked up a 2007 base Escalade for peanuts and I’ve been fixing little things here and there. I’ve had an intermittent clunk when it shifts under light load which I’ve managed to replicated by shifting back and forth while
Stationary from drive to reverse, with my kid shifting it back and forth I crawled underneath and I see that the front driveshaft turns a considerable amount vs the rear, almost 180 degrees before stopping and causing the clank. It’s like there’s tons of backlash in the front diff, anyone else experience this? Trying to figure out if it’s a diff issue or transfer case issue but it’s looking like the diff. With the amount of play it has I’d swear it’s missing a tooth or something.

 

[B-train]

I've noticed that on these vehicles, but not to that extent. I have a 2008 Denali, and I've noticed the slop in the front connection, but I service the front diff religiously since I've owned it. I do get a similar clunk sometimes on a downshift, and I've seen that same thing on other model year denali's as well. Mine has 193,500 miles, not sure what yours has.

I'd drop the fluid and see what you are working with. Luckily, these diffentials are plentiful and cheap from bone yards. It'll take you about 1 - 2 hours to replace it if you don't have a lift. Super easy, just make sure it's the same gear ratio.

 

[donjetman]

@Discodisco
use the search fuction here, "Clunk" & "KlunK", this has been discussed a lot here.

 

[Discodisco]

I searched and found one thread that ended up being a diff mount, my Diff mounts are brand new delco units. All fluids are new, engine mounts new.

 

[Fless]

Transmission mount condition?

 

[Geotrash]

I searched and found one thread that ended up being a diff mount, my Diff mounts are brand new delco units. All fluids are new, engine mounts new.

That seems like a lot of backlash for the front diff. My 2007's will turn a little bit but nothing like that.

 

[Discodisco]

Transmission mount condition?

It looks to be in decent shape, im going to get a vid and post shortly.

 

[Discodisco]

That seems like a lot of backlash for the front diff. My 2007's will turn a little bit but nothing like that.

Check this out, you can see the shaft sort of jolt and clunk/clank.

https://imgur.com/a/1YYFZbZ

 

[Geotrash]

Check this out, you can see the shaft sort of jolt and clunk/clank.

https://imgur.com/a/1YYFZbZ

Ah, that's not too bad at all. That's not 180º, which would have been excessive. Next step: get a cheap mechanics stethoscope from autozone and do exactly what you recorded but with the tip of the 'scope on the front diff housing, then the transfer case, then the diff mount areas to pinpoint where the clunking noise is coming from. My bet is it's backlash in the transfer case chain.

 

[Discodisco]

Ah, that's not too bad at all. That's not 180º, which would have been excessive. Next step: get a cheap mechanics stethoscope from autozone and do exactly what you recorded but with the tip of the 'scope on the front diff housing, then the transfer case, then the diff mount areas to pinpoint where the clunking noise is coming from. My bet is it's backlash in the transfer case chain.

Here's my question... I do primarily hear it form the transfer case but I dont see that kind of movement from the rear driveshaft when doing the same thing, would the slack in the chain cause that?

 

[Geotrash]

Here's my question... I do primarily hear it form the transfer case but I dont see that kind of movement from the rear driveshaft when doing the same thing, would the slack in the chain cause that?

Same with my '07 XL Denali. I only see that kind of play on the front driveshaft because that's the shaft that's driven by the chain inside the transfer case. The rear driveshaft is direct-driven off the transmission output shaft, so any play in the rear differential isn't going to be felt by trying to turn the rear driveshaft. That's why I say it's important to get a stethoscope on that transfer case, so you can confirm that that's where the noise is coming from. Super common to have that much slack in the transfer case chain on higher mileage AWD GMT900 rigs, by the way.

 

[petethepug]

Congrats from SoCal on the 08. Welcome to the benefits of the 07/08 L92 6.2L motor without AFM/DOD.

Info below on an owner of two 07 Escalade ESV. One was a business Limo. TLC is an understatement on the Resto of his vehicles. You’ll pick up almost every detail you need on your truck here…

https://www.cadillacforums.com/threads/new-member-and-my-esv-adventure.1092929/page-83?post_id=18317127&nested_view=1&sortby=oldest#post-18317127

Did you press new bushings into the front diff mounts or buy new ones? ChiefM pressed in new bushes the 1st time and they failed. He ended up purchasing the entire assembly because they’re cheap. It fixed the clunk.

He also used a rebuild kit on the xfer case @ 200k mi. He wasn’t 100% pleased w/ the rebuild and swap’d in a low milage used unit. That cured the rest of the clunk.

 

[Discodisco]

Ah, that's not too bad at all. That's not 180º, which would have been excessive. Next step: get a cheap mechanics stethoscope from autozone and do exactly what you recorded but with the tip of the 'scope on the front diff housing, then the transfer case, then the diff mount areas to pinpoint where the clunking noise is coming from. My bet is it's backlash in the transfer case chain.

Here's my question... I do primarily hear it form the transfer case but I dont see that kind of movement from the rear driveshaft when doing the same thing, would the slack in the chain cause that?

Congrats from SoCal on the 08. Welcome to the benefits of the 07/08 L92 6.2L motor without AFM/DOD.

Info below on an owner of two 07 Escalade ESV. One was a business Limo. TLC is an understatement on the Resto of his vehicles. You’ll pick up almost every detail you need on your truck here…

https://www.cadillacforums.com/threads/new-member-and-my-esv-adventure.1092929/page-83?post_id=18317127&nested_view=1&sortby=oldest#post-18317127

Did you press new bushings into the front diff mounts or buy new ones? ChiefM pressed in new bushes the 1st time and they failed. He ended up purchasing the entire assembly because they’re cheap. It fixed the clunk.

View attachment 440917

He also used a rebuild kit on the xfer case @ 200k mi. He wasn’t 100% pleased w/ the rebuild and swap’d in a low milage used unit. That cured the rest of the clunk.

I used the complete bracket, you can see in the video its def not moving the diff housing around, what you guys are saying makes a lot of sense, I might just buy the chain and seal kit and crack it open. The sound is def louder at the transfer case even without a stethoscope I can tell.

 

[Geotrash]

Here's my question... I do primarily hear it form the transfer case but I dont see that kind of movement from the rear driveshaft when doing the same thing, would the slack in the chain cause that?

See my answer to that in post #11 above.

 

[petethepug]

I think @swathdiver was going to have his xfer case rebuilt recently. Maybe he has some recommendations based on his experience.