Wheel speed knock (1 Viewer)

[MrGB]

Hi all,

Wondering if anyone has experience with a knocking sound as they slow to a stop on a manual fzj80?

I notice the dull this / knock matches the wheel speed quite closely. That is the sound repeats more slowly as I come to a stop.

My guess is front front drive shaft as I feel quite a bit of play in it compared to the rear drive shaft.

If you've heard and solved a similar sound, it's be great to hear from you.

Cheers
Garry

 

[BILT4ME]

Wheel
Lug nut
Wheel bearing
U-Joint
Transfer case bearing
Bad tire
Rock in the brake pads.

Could be lots of things.

 

[-Spike-]

Hi all,

Wondering if anyone has experience with a knocking sound as they slow to a stop on a manual fzj80?

I notice the dull this / knock matches the wheel speed quite closely. That is the sound repeats more slowly as I come to a stop.

My guess is front front drive shaft as I feel quite a bit of play in it compared to the rear drive shaft.

If you've heard and solved a similar sound, it's be great to hear from you.

Cheers
Garry

The driveshaft spins about 4 times faster than the wheel. I'd pull the wheels off and look for issues, such as rocks flopping around in there, loose bearings, loose calipers, loose wheel weights, loose lug nuts, etc.

 

[rolliges]

Check tire pressures and for tire deformities (bulges).

 

[MrGB]

Thanks @rolliges

Wheel - no recent offroading so unlikely any new damage
Lug nut - checked all
Wheel bearing - redone in the last 10k so presume ok
U-Joint - one was replaced but will need to check which
Transfer case bearing - is there a way to check this you can recommend?
Bad tire - same as wheel
Rock in the brake pads - possible will take a look

Other things I've noticed since:
Front drive shaft rotates freely about an inch (2.5cm) while still on the ground. Is this normal? The rear is much less.

Appreciate any guidance

 

[-Spike-]

One possible issue that it could be- a chipped or broken ring gear. Might explain the free play in the drive shaft. Best way I know of to take a look is a snake cam, aka endoscope or borescope.

 

[Heckraiser]

Wheel bearings redone in the last 10k--I would not presume these are OK because they have been recently done. It's really common for these to loosen up when they're installed at FSM preload (which is too light for heavy usage or larger-than-stock tires).

 

[MrGB]

Quick update. Turns out the drive flanges were toast and hadn't been replaced when installing new cvs. This has taken care of a considerable amount of the backlash, but that mysterious knock is still there.

Being that the wheel, callipers etc were all off to do the flanges and the diff is reportedly fine, I'm still at a loss. The front drive shaft still rotates about 1\8 of a rotation but by all accounts that could be normal.

Fingers crossed it's not a problem that I learn the cause of out on a track in the middle of nowhere.

 

[Woofythewolf]

Mine rotates about 1/2 an inch when on the ground. 310-380k miles. (odometer broken but probably 380k)

Does turning have any effect on it? (faster for a given speed while turned left vs right). Could narrow it down to left side, right side, or pinion/gear related if no change. Maybe do some big S turns in a parking lot while going downhill.