Reverse Lock up & wheels screech to halt

[Driven]

Hoping to get some help with diagnosing a 280SL Auto.

Forward gears operate normally. Reverse works normally half the time.

The other half, car will reverse anywhere from several feet to couple car lengths and the wheels lock up abruptly (screeching) to stand still.

If throttle, the car will move again, but lock at some point.

It is not the braking system. Am unable to reproduce the problem on a lift with wheels off the ground.

Bit of grinding noise coming from rear at initial accel and decel.

Could this be the split axle yoke/u-joint binding, differential, or the transmission?

Thanks in advance!
 

[Pawel66]

I had similar symptoms in ny W463 and it was one of the wheel bearings. The car was not brought to halt maybe, but slowed down by it and it was making noise as you describe.

[Shvegel]

The only thing I have seen in my experience that does that is the shaft that retains the spider gears in the rear axle coming loose. If that is the case you will most likely be looking for a new axle.

[Mike Hughes]

During a driving tour in 1993 a total lockup of one of the vehicles in the middle of Smoky Mountain National Park in North Carolina was caused by one of the bolts securing the ring gear to the differential carrier backing out until it was proud enough to foul with an internal boss in the differential housing.  By the time a tow truck finally arrived several of us has gotten the rear axle apart, identified the problem, put it back together again minus the differential carrier, and pushed the car to the side of the road.  The owner and his wife accompanied the car to the nearest town, where the tow truck driver called his buddy who owned the NAPA parts store and a gas station. The upshot of all this is that they got the car back together and on the road in time for them to arrive in their car at the restaurant in Gatlinburg, Tennessee where the rest of us were dining that evening before dessert was served.

[Driven]

Appreciate comments with thanks.

Unfortunately it's not the wheel bearings. No play or noise. Stoppage is head bobbing abrupt.

2 votes for axle...

Anybody for transmission, and is there a way to eliminate it as the culprit?
- Have read failing bands will do the same but never experienced myself.

[Benz Dr.]

Loose E brake material on the shoe?

[ja17]

Remove the drain plug and check for metal pieces in the fluid and bottom of the diff. case. Using a flashlight, you can also inspect each tooth of the ring gear for any marks or damage.

[Shvegel]

I like Dan's (BenzDr) answer too.  First place I would look as it is the easiest to access.  Especially if it is locking up only one wheel.

[Driven]

Again, Thanks for inputs.

Tried reproducing symptoms by manually yanking hard on hand brake but the stoppage is comparatively linear. The binding feels occurs instantly. 

Car on the lift today. did not peer into the drain/fill holes of the diff but did let fluid out. Inspection revealed clean fluid, no material at all. (don't have previous history, PO could have just changed the fluid)

New observations during testing today, hope you guys spot something revealing.

Binding occurs when reversing very slowly, zero to light pressure on brakes. As it's building up to idle speed or coming off of it. Doesn't happen under throttle.

Once binded but still in reverse gear, car will stay stationary. And will stay that way with foot off brake/throttle.

• Pushing it manually backwards slowly is possible but can hear a ratcheting noise from underneath. Stop pushing and car returns to a stop.
  
• In another instance, it was not possible to push the car manually, stayed binded.

In both instances above: Shifting gear to neutral whilst binded and pushing manually backwards, will instantly unbind and free the car up.

If this was an axle issue, is there any reason to explain correlation between shifting into neutral to freeing up whatever is binding?

[stickandrudderman]

Sounds like it might be dropping into "P" (park).

[Driven]

Sounds like it might be dropping into "P" (park).

Right, that would follow symptoms... thank you. Does anyone know how to check or service this in a K4A025?

https://www.youtube.com/watch?v=UUNslRQihis

Can see it here in the cut out.

[Neil Thompson]

Could it be as simple as badly worn gear linkage bushes?

Neil

[Shvegel]

In theory worn bushings should cause the linkage to push less on the transmission linkage.  I shouldn’t cause it to shift it into park.

[ja17]

Sounds logical,  I'll jump on board with the linkage theory at this point

[Neil Thompson]

The linkage and bushes are much easier and cheaper to check than dismantling the gearbox, we all know how troublesome they can be

[Driven]

Thanks for everybody's comments.

Did attempt to manually push forward when binded and still in reverse gear. No budge at all, could feel was pushing against engine power. The transmission in Park gives a little bit due to lash. Pushing backwards manually was possible (with ratchet noise).

I wish it was the linkage or a bushing but it did not appear the car was actually in park.

Any suggestions for other testing methods?

[Driven]

Video of issue

https://www.youtube.com/watch?v=i2TFoKyl8SQ&feature=youtu.be