Issue in Reverse

[orttauq]

I have a new issue I need help finding/diagnosing. 97 Supercharged LX450 with 212K.
In reverse under heavy load, such as backing up a trailer or backing up a hill I get a short grinding/binding noise that, quite frankly, is very scary. I would get a recording but I am not sure if this is causing heavy damage.
Describing it as best as I can it sounds like something is binding up and then when I lift off the throttle it unbinds. The second sound is a reverse of the first (hope that makes sense). It has a bit of metal on metal but also has a bit of twisting rubber squeak too.
The binding/grinding noise sounds like it is coming from right front and it feels as if this causes the truck to stop moving. The engine does not race so it is still under load, and the truck does not roll forward so there is still torque to the drive-line.
This has never happened in forward gears, only reverse and I even put it in 4lo so see if it was the TC.

TIA Eric

 

[baldilocks]

Remove the grease caps from the front drive flanges/plates and inspect for signs that the splines in the flange gave up allowing the axle shaft to spin rather than put power to the ground.

 

[FJP971]

Grinding in Reverse

 

[Haspin FJ]

Saw this written by L8Shift on one of the linked posts:

"I back-up on a hill when I parallel park in front of the house.... I usually wait ~5 seconds in reverse before giving it any gas....

If I give it gas immediately after I go into reverse (on the hill), I get the chatter noise, and go no where. "

I have 340k (history before 319k unknown) but the tranny runs great but I have had this happen as well in reverse. First time not long after I got it. I got in a habit of doing what is stated above and totally forgot about this issue until I just saw this post (I've also changed the fluid with the standard 4 qt change with Valvoline Max life several times). I'm sure if I just threw it in reverse and punched it it would still happen but mine seems to be fine if your nice and friendly with it (may take a second to build pressure after the shift to r??). I only give it like 2 seconds though. Ive had it on some pretty decent four wheeling all this last summer without an issue. I haven't heard it in a year or two following this practice.

 

[Dirty Koala]

have you tried removing one shaft at a time to see if you can isolate front diff, rear diff, trans vs xfer case?