Kraton Slight whirring noise, never heard before

[chrisexv6]

Yesterday I noticed our Kraton making a slight whirring noise, mostly if the front end lifted off the ground (wheelie, bump in the yard, etc). I hadn't heard it before, but recently replaced the pinion with a 16 tooth Tekno. I assumed it was the pinion mesh at that point, reset it last night but I still hear it today.

The diffs seem OK...I did not tear them down, but I did check each for no slop, no clicking, no notchiness, etc.

Video attached. Might be hard to pinpoint over the metal gear noise, but my best description is the kinda "whirring" "whining" it makes under high throttle and as the wheels are spinning down if you lower the throttle amount.

Thanks.

-Chris

 

[Overpowerrc]

Sound normal to me?‍

 

[FatCatRC]

Yeah sounds good to me, you might wanna clean all those threads or grass whatever is hanging off it. You could have sucked some of that into a bearing etc.

 

[hobo]

Yesterday I noticed our Kraton making a slight whirring noise, mostly if the front end lifted off the ground (wheelie, bump in the yard, etc). I hadn't heard it before, but recently replaced the pinion with a 16 tooth Tekno. I assumed it was the pinion mesh at that point, reset it last night but I still hear it today.

The diffs seem OK...I did not tear them down, but I did check each for no slop, no clicking, no notchiness, etc.

Video attached. Might be hard to pinpoint over the metal gear noise, but my best description is the kinda "whirring" "whining" it makes under high throttle and as the wheels are spinning down if you lower the throttle amount.

Thanks.

-Chris

sounds normal to me

 

[chrisexv6]

Not sure if related, but the motor ate another pinion.

Tearing it all down now, I think the motor mount is tweaked a bit.

If I grab the motor shaft there is a very very very very small amount of up/down play. Took off the cap (pinion side), the bearing feels smooth and spins easily.

Hoping the motor mount being tweaked was the issue, have a new one on the way for now.

 

[olds97_lss]

Kind of sounded like a dry bearing howl at the beginning. Might want to replace the motor bearings just in case.

My outcast was howling like that the other day, all the bearings seemed ok, but I put a drop of oil on all the ones I could see, then yesterday one of the diff bearings grenaded.

 

[chrisexv6]

Kind of sounded like a dry bearing howl at the beginning. Might want to replace the motor bearings just in case.

My outcast was howling like that the other day, all the bearings seemed ok, but I put a drop of oil on all the ones I could see, then yesterday one of the diff bearings grenaded.

Any tips on pinpointing which one(s) might be dry?

We have some spare diff bearings, but no motor bearings. I can order some off McMaster, but figured if I need more than one I might as well order at the same time. They all run smooth, but I don't know how to tell if they are dry (me spinning them by hand is not the same as them screaming at wide open throttle )

 

[Harlon]

Sounds ok yo me but if it's sounded different to you then someone is definitely going on. I'd bet your bearings are getting worn out. When was the last time you changed them? If you havnt ever changed them, definitely go ahead and put rubber sealed bearings in her. Fast eddy sells krwton bearing kits. ??

 

[chrisexv6]

@olds97_lss thanks for the dry bearing hint. Since the center diff was already out, I pulled it apart to get to the bearings and sure enough the front side one was completely empty of grease or oil. The rear one had some grease in it, but I cleaned both of them and re-greased with marine grease.

The truck was purchased used and the bearings were already replaced with rubber sealed units from Fast Eddy. We've put probably 15-20 packs through everything already, so it might just have been time.

I do have another set of motor bearings on the way, but once a straight motor mount arrives Im going to put it all back together and try to run it. I have a feeling the howling will go away, but want to make sure we arent still eating pinions.

Thanks again.

 

[olds97_lss]

I thought my dry bearing was the front side of the center diff or one of the front bearings. I kept the rear tires on the ground and lifted the front, then ramped up the throttle and it would howl. After putting a drop of oil on all the bearings I could see, the howl went away, but then the rear bearing on the center diff grenaded on me. I haven't tore into it yet. Since I have to tear the diff down to replace the bearings, I'll likely dig through my stuff for some old output cups and replace those as mine are getting worn pretty bad in the center.

 

[chrisexv6]

I thought my dry bearing was the front side of the center diff or one of the front bearings. I kept the rear tires on the ground and lifted the front, then ramped up the throttle and it would howl. After putting a drop of oil on all the bearings I could see, the howl went away, but then the rear bearing on the center diff grenaded on me. I haven't tore into it yet. Since I have to tear the diff down to replace the bearings, I'll likely dig through my stuff for some old output cups and replace those as mine are getting worn pretty bad in the center.

As I was running it for the video yesterday I tried to pinpoint the area of the noise...it sounded like it was in the motor/center diff area, so the dry bearing there makes sense.

Im not sure if that was a partial (or full) cause of the pinion wiping out, but the new motor mount should be here tomorrow so I can put it all back together. I have ceramic bearings on the way for the motor, but Im not sure my driver wants to wait that long!