The whole drive shaft shakes while putting into reverse

[John23562]

https://drive.google.com/file/d/13eOSnmuOk2kov8GphjRDWuq8J8nkN7Q1/view

 

[superj]

Link doesn't work

 

[John23562]

Link doesn't work

Fixed it

 

[superj]

What is your trucks idle speed? It seems like maybe idle speed is high and torque converter is acting up?

Let the smart guys see whats going on though because thats a heck of a jump. Like its nor changing gears properly

 

[pjtoledo]

wow, that's different.

 

[alwaysFlOoReD]

Motor mount

 

[John23562]

IMG_4862.MOV

drive.google.com

This is from the rear differential

 

[alwaysFlOoReD]

Hmmm.
While taking a video of engine from center front of truck;
1) Rev the engine quickly while in neutral.
2) Rev the engine quickly while in drive, foot hard on brake.
3) Rev the engine quickly while in reverse, foot hard on brake.
Post results.

 

[arse_sidewards]

Sure looks from that drive shaft video like the engine is jumping all around.

 

[pjtoledo]

IMG_4862.MOV

drive.google.com

This is from the rear differential

it looks like the flange is bouncing, that ain't good.
grab the shaft/flange at the rear axle and check for any movement other than rotational.
yes it should rotate some when stationary, absolutely no up/down or sideways.

do in neutral
EDIT:
while viewing the video in slow motion it's hard to tell if the diff is rotating down because of torque , or the flange is jumping.

 

[SenorNoob]

I can't see any way that engine could move that much without a bad mount. Looks like mine when drivers' side mount decided to not be bolted to the block anymore...

 

[ekrampitzjr]

Check the whole frame carefully rear to front, especially around the engine and transmission mounts. You're in California, so the truck might not have been exposed to salt, but frames can still rust.

 

[pentode]

it looks like the flange is bouncing, that ain't good.
grab the shaft/flange at the rear axle and check for any movement other than rotational.
yes it should rotate some when stationary, absolutely no up/down or sideways.

do in neutral
EDIT:
while viewing the video in slow motion it's hard to tell if the diff is rotating down because of torque , or the flange is jumping.

Is anyone else seeing the axle twist forwards? It looks at first like the flange or pinion is jumping but the more I look at it it looks like axle wrap.

 

[pjtoledo]

it kind of appears rotation is started, not much happens, then something skips/jumps giving the engine/shaft a tiny fraction of time to rotate.
then it slams into the end of whatever is skipping/jumping. that could possibly explain the sudden jerk.

cheap test, put the rear on jack stands. with no load is the jerk the same?
while up rotate wheels slowly feeling for catches/bumps.

the rear input can have quite a bit of rotational play, but not clunks/jerks/bumps..

 

[pjtoledo]

Is anyone else seeing the axle twist forwards? It looks at first like the flange or pinion is jumping but the more I look at it it looks like axle wrap.

viewing it at 0.2 speed, the flange rotation and diff jumping down occur simultaneously.
it would seem the diff is responding to a sudden impulse of torque, and the springs let the housing rotate. the wheels on the ground are effectively restricting the wheels/axles.
reminder, forward = diff up, reverse = diff down.

poster/John, what happens if you put it in reverse then just sit stationary with the brakes applied for a minute or 2?
give it a little gas, but try not to let it move.