Rear Wheel Lockup

[greedyshark]

I own a ‘99 Tahoe. 2-wheel drive/Police package. 317K miles. As of late, when driving, the rear wheels will, all of a sudden, lock up bringing the truck to a screeching stop. It occurs at various speeds, during both acceleration and deceleration. No brakes are being applied when it happens. Two mechanics have looked at it checking the brake system, transmission, and rear differential. Neither can identify a problem. Thoughts?

 

[89Suburban]

Find some better mechanics dang

Check the parking brake components

 

[greedyshark]

Find some better mechanics dang

Check the parking brake components

Both mechanics checked parking brake components. No issues.

 

[89Suburban]

Any warning light or codes when this happens? This is very strange.

 

[greedyshark]

Any warning light or codes when this happens? This is very strange.

Nothing. It just happens. On one occasion I was approaching an intersection. Speed approximately 20mpg. Locked up. Another occasion accelerating from standing. Speed between 5 and 10mpg. Locked up. Latest instance was locking at 45mph. Thankfully no one was behind me at the time. Truck is now garaged until I can find a solution.

 

[Sam Harris]

How’s the rear end..? Any noises.? When was the last service done?

 

[Joseph Garcia]

My thoughts are around the rear end failing in some fashion. Has anyone opened up the cover on the rear end and inspected it?

 

[Marky Dissod]

I own a ‘99 Tahoe. 2-wheel drive / Police package. 317K miles.
As of late, when driving, the rear wheels will, all of a sudden, lock up bringing the truck to a screeching stop.
It occurs at various speeds, during both acceleration and deceleration. No brakes are being applied when it happens.
Two mechanics have looked at it checking the brake system, transmission, and rear differential.
Neither can identify a problem. Thoughts?

After it locks up, does it unlock? How did you get it back home?

Securely get your Tahoe (Z56?) off the ground with rear wheels & tires off as well. Take every safety precaution.

Safely secured, up in the air, 'drive' until the problem replicates itself.
Should be easier to inspect the rear axle immediately after the fault to find out if there's anything wrong with it.

Can't think of any 4L60E weirdness that would explain this behavior. My bet is something wrong with the rear axle.
At 317,000miles, you could simply try installing a different / younger one ...

(Was GM's original tire spec for your Tahoe PPV 235/70VR15? If not, what was it? Just curious to check ...)

 

[89Suburban]

I don't understand how any type of mechanics could look at this vehicle and not find the problem, that is a major malfunction.

 

[greedyshark]

How’s the rear end..? Any noises.? When was the last service done?

Rear end is fine. No noises.