2Yrs Unsolved Binding/Knocking Suspension During Sharp Turns

[swathdiver]

Sounds reasonable to start with a fluid change for the TC. The holidays have already drained most of my budget.

Is there a specific identifier that will tell me what type of TC is on the vehicle, so I can specify the correct fluid? I know shops can source this kind of thing, but I suppose it's for my own piece of mind so I know what to expect when the mechanic tells me.

Transmission fluid is red, the Autotrac fluid is kinda blue. It's called Auto Track fluid and the original part number is: 12378396

 

[Fless]

Transmission fluid is red, the Autotrac fluid is kinda blue. It's called Auto Track fluid and the original part number is: 12378396

Does the AWD transfer case take Auto Trac II fluid? I thought that it takes transmission fluid. @Rocket Man

 

[swathdiver]

Does the AWD transfer case take Auto Trac II fluid? I thought that it takes transmission fluid. @Rocket Man

I went poking around in different owner's manuals and came up with that. I have been known to be wrong once in a while! LOL

 

[Fless]

You're busted, @swathdiver!

From the horse's mouth: (obviously newer compatible Dexron fluid should be used)

 

[THarber]

I'd re-exam both front hubs as well as upper and lower ball joints.

Tim

 

[swathdiver]

You're busted, @swathdiver!

From the horse's mouth: (obviously newer compatible Dexron fluid should be used)

View attachment 357912

But wait! There's more:



That page is from a 2000 GMC Yukon owner's manual. I went with this because it says, "Automatic Transfer Case".

Ok, so which is right?

 

[Bill 1960]

GM has created a confusing mess of terminology and branding on this topic.

Automatic 4wd is not the same as AWD.

I have the NP246 “Autotrac” transfer case with auto four wheel drive. But it doesn’t use “Auto-trak” transfer case fluid, it specifies Dexron 6 in my manual. I have seen other contradictory information elsewhere.

2008 Tahoe manual (Auto 4x4 the only option):


The AWD TC with full time AWD and the viscous coupler is a different item.

YMMV I’m sure they changed the spec over time.

For the OP; just check your manual, which is available online from GM if you don’t have the original.

 

[rockola1971]

Yup Auto Tcase is not the same as a AWD Tcase when it comes to the fluid used. I also believe somewhere in 2006 or so that the AWD Tcase fluid spec changed because of a different model AWD Tcase?
The Auto Tcase relies on the autotrac fluid for its clutches for the the "auto 4wd" feature. Put Tranny fluid in there and it wont end well for the Tcase.

 

[Wunderground]

This is really good information folks! Thanks for the response.

Since there was little regular maintenance performed before I owned the truck, I've scheduled it at the shop on Monday (Dec. 20th) for a TC fluid change.

I'll report back afterwards.

As for the fluid referenced in my manual? It states "DEXRON -III Automatic Transmission Fluid."

 

[Fless]

This is really good information folks! Thanks for the response.

Since there was little regular maintenance performed before I owned the truck, I've scheduled it at the shop on Monday (Dec. 20th) for a TC fluid change.

I'll report back afterwards.

As for the fluid referenced in my manual? It states "DEXRON -III Automatic Transmission Fluid."

Yes; I posted the page from the OP's 2002 Denali manual. Context matters.