Let's sift through every square inch of a 2013 Tahoe PPV

[Caddylack]

It definitely seems like the left rear isn’t spinning very fast.

 

[Caddylack]

Posi is toast, eh?

 

[Caddylack]

The shop I just talked to thinks it’s just normal since I don’t have 4x4 but this seems ridiculous.

 

[Marky Dissod]

You're supposed to have a G80, right? If it's a 'locker' that won't lock over 25MpH, which is what GM gave you, that's one thing.
But if it won't even lock UNDER 25MpH, it's time for a torque sensing limited slip diff already.

 

[iamdub]

The shop I just talked to thinks it’s just normal since I don’t have 4x4 but this seems ridiculous.

How fresh is the fluid in it? The Eaton Gov-Lock's operation is sensitive to the condition of the fluid. Mine would have problems unlocking but has been working perfectly since I replaced the fluid, including a thorough flushing of the differential bits to get all the old fluid out.

 

[Caddylack]

How fresh is the fluid in it? The Eaton Gov-Lock's operation is sensitive to the condition of the fluid. Mine would have problems unlocking but has been working perfectly since I replaced the fluid, including a thorough flushing of the differential bits to get all the old fluid out.

I have never even checked the rear diff fluid, TBH. It may well be original.

Now that you’ve brought it to my attention, I’m wondering about the temperature aspect.

I have issues every single year with my trans fluid freezing, so it’s not far fetched to think the rear diff fluid may also be vulnerable. I can’t even use cheap power steering fluid because the wheel will be completely locked in the morning.

 

[iamdub]

I have never even checked the rear diff fluid, TBH. It may well be original.

Now that you’ve brought it to my attention, I’m wondering about the temperature aspect.

I have issues every single year with my trans fluid freezing, so it’s not far fetched to think the rear diff fluid may also be vulnerable. I can’t even use cheap power steering fluid because the wheel will be completely locked in the morning.

Being where I live, I'm terrible at considering freezing temperatures. The Gov-Lock requires an oil with special friction modifiers to operate properly. So, if it's full of wear debris, making it thicker, I could see how being more viscous from freezing temps could really alter its function.

Load up on some brake parts cleaner (I like the Super Tech from Walmart cuz it's cheap but effective), get a new gasket and some oil. I use Mobil synthetic (75W90), I think) cuz it works for the clutched and non-clutched differentials. But, you might need something else for your environment. I'd suggest you inspect the axle seals behind the brake rotors cuz now, with the rear opened and drained, would be a prime opportunity to replace them and maybe the bearings. If they're original, you might wanna replace them as a PM so you don't have to open it up and drain the oil again later.

 

[Caddylack]

Looks like I’m going to put the Tahoe on the waiting list to get ripped apart and rebuilt.

Should be a fun 2024.

 

[iamdub]

Looks like I’m going to put the Tahoe on the waiting list to get ripped apart and rebuilt.

Should be a fun 2024.

What kinda "rebuilt" are you talking here?

 

[Caddylack]

What kinda "rebuilt" are you talking here?

Well… It would be a pretty mild refresh:

DOD delete with maybe a Torquer?
Supporting valvetrain
Built 6L90E, some converter
Those huge sway bars I bought a while back
Suspension maintenance, etc.