Weird sound (1 Viewer)

[MikePL]

So we bought this LX450. I know this model almost inside-out but this sound has me puzzled. Why puzzled? Because the truck has 90k miles on and it is really unusual for such a low mileage to make any weird sounds. I used to deal with 200K mile rigs without any sounds...

Check out the last seconds of the video:


It's a ratcheting sound.

What we did so far:

- OME springs and shocks
- Dobinsons caster plates for the front axle
- new u-joints in the front driveshaft
- adjustable panhards
- we also preloaded the wheel bearings because the wheels had around 1/2in of play at the 12 and 6 o'clock position. We don't know how long the truck had been driven with loose front wheel bearings.
- no visible/feelable lateral play when yanking at the differential flange and t-case flange. All seems laterally stiff. A few degrees of backlash at the front diff flange.

This is snow so the load on the drivetrain doesn't seem extreme because of a low-traction surface but there is this ratcheting. When driving on the freeway at around 40-70mph there is a growling sound and a bit of vibration. We changed the u-joints and it didn't go away. We adjusted the bearings and it didn't go away.

The transfer case is gear driven so it is not a loose chain because there is no chain.

I am out of ideas.

 

[NeverFinis]

Have you redone the front axle? Do the birfields have grease? I didn't see that in your list.

Birfields will make a clicking sound when worn.

 

[jpoole]

It sounded like birfs to me. They are under more stress and more likely to click when the center diff is locked, the front wheels are turned and there is power being delivered to the wheels.

Check grease levels in the knuckles and add some moly as needed to minimize damage until you can do a full axle service/rebuild. At that time you may end up wanting to change out the birfs or swap them side to side depending on how they behave with grease added and how they look on inspection.

 

[MikePL]

Wow, I forgot about the birfs. Probably because I has to do them in my rig and it was an ordeal I wanted to delete from my brain (with success). Yeah, that's a clicking typical to a CV joint going bad. I wonder if the on-road growling is also due to the birfs.

 

[jpoole]

On-road growling could be the bushing inside the spindle, if the grease is mostly gone.

Also, if you get the clicking on pavement when the center diff unlocked sometimes it's an early indicator of a stiffening/failing viscous coupler. Not trying to cause excess scope creep here but wanted to let you know that clicky birfs can be a good indicator for the VC. That also means that if the birfs click readily with CDL engaged but not with it disengaged that your VC is still relatively free

 

[BILT4ME]

Wow, I forgot about the birfs. Probably because I has to do them in my rig and it was an ordeal I wanted to delete from my brain (with success). Yeah, that's a clicking typical to a CV joint going bad. I wonder if the on-road growling is also due to the birfs.

Also need to look at the drive flanges on the front hubs. If they are heavily worn they may start to ratchet.

I think the noise is the birfs.

 

[COS80]

Sounds like a rolled-back odo.

 

[Kernal]

It's not unusual IME to find an 80 that's never had regular service on the front axle (grease added to the knuckles, Birfs/CV joints pulled and repacked, spindle bushing inspected/greased---).

A quick check of the grease level in the knuckles then if low pump a 14oz tube of a high moly content grease (3-5%) like Valvoline Palladium into each knuckle and go for a drive.

 

[LongDuck]

That sound is more than $1500, but less than $3500. I've owned my 80 for 10+ years, so I can speak with some authority on this matter.

 

[NeverFinis]

I mean, if you don't mind getting greasy, it could be as low as $250 for two no-name new birfields, and a seal kit. To me, birfields are disposable.