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.

 

[greedyshark]

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

Agreed. Both mechanics are trusted.Both are scratching their heads.

 

[greedyshark]

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

All break components have been removed/inspected. Rear differential haas been opened/inspected.

 

[greedyshark]

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 ...)

After it locks, it unlocks within a couple of seconds, sometimes smoothly, sometimes with a few residuals jerks. Axle was inspected. No issues. I’ll get back to you on the tire specs.

 

[camaroz2887]

Interested to hear the answer, had a buddies 02 or 03 sierra do the same thing at 75mph on route 1 in NJ when I was like 16. It made a Smoke show and spun down to a stop then had headlights coming through the smoke wall at us…

Not fun but he drove away couldn’t find an issue and drove the vehicle another 100,000 miles with no issues(absolutely not telling you to do this).
He did have aftermarket limited slip unit I always swore was the cause tho.

 

[Marky Dissod]

He did have aftermarket limited slip unit I always swore was the cause tho.

I'm more than a wee lil bit afraid of the On / Off nature of the OE G80 in my Z71.
Whenever I've enough loose cash, I'll replace it with a TorSen limited slip

 

[mikehooo]

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?

How do you get it to “unlock” ?

 

[NickTransmissions]

After it locks, it unlocks within a couple of seconds, sometimes smoothly, sometimes with a few residuals jerks. Axle was inspected. No issues. I’ll get back to you on the tire specs.

This could be transmission-related, specifically rear gear train failure.

The rear ring gear, planet or sun gear will begin to chip teeth and those pieces will wedge between the rest of the gears, temporarily preventing mesh. It will not generate code and usually only confirmed by dropping the pan and seeing pieces of gear teeth on the bottom.

 

[B-train]

Have you tried disabling the ABS/TRACTION CONTROL and driven it?

Here's my list of potentials (some already mentioned by other dudes)
1. Emergency brake shoes/hardware broken and jamming in the drum (I would think only affected wheel would lock up though)
2. Faulty ABS/TC. Are all 4 tires the same size?
3. Metal debris in rear end (spider gear(s) sheared off and floating around). Once they get in the pinion it will act as an instant parking brake for both wheels.
4. Last idea....long shot here. Maybe a valve body issue with the trans and its engaging a reverse scenario.

 

[NickTransmissions]

Have you tried disabling the ABS/TRACTION CONTROL and driven it?

Here's my list of potentials (some already mentioned by other dudes)
1. Emergency brake shoes/hardware broken and jamming in the drum (I would think only affected wheel would lock up though)
2. Faulty ABS/TC. Are all 4 tires the same size?
3. Metal debris in rear end (spider gear(s) sheared off and floating around). Once they get in the pinion it will act as an instant parking brake for both wheels.
4. Last idea....long shot here. Maybe a valve body issue with the trans and its engaging a reverse scenario.

#4 could happen if the manual valve somehow becomes disconnected from the linkage arm that connects to the rooster comb but the entire vb would have to somehow come loose and drop down by at least 3” or so.

#3 is also possible, pieces of teeth wedging, interfering with the mesh but id suspect accompanying vibration from rear end, esp if it is happening at speed…

 

[DuraYuk]

U joints and rear wheel bearings need to be inspected.