Grinding noise

jeepercreeper13 · 08-14-2012, 08:20 PM

I'm having a loud grinding spinning noise starting around 35mph. It's quiet when I'm on the throttle but when I shift from 4th to 5th while the clutch is in the noise appears. Also if I put it in neutral the noise is constant. If I'm just cruising with my foot barely on the throttle it will make the noise. The only time it doesn't make the noise is at low speeds or if I'm on the throttle. I was thinking the noise may be coming from the transfer case? Any ideas what it might be?

mukluk · 08-15-2012, 10:35 AM

Hard to say. Try narrowing down the conditions that the noise occurs... does putting it in 4hi make a difference? Does it still make noise with the rear driveshaft removed and driven in 4wd? Does it make noise sitting still with the transfer case in neutral and the transmission spinning in gear?

Also, just to clarify, when you say it is constant in neutral do you mean in motion or sitting still?

jeepercreeper13 · 08-15-2012, 02:59 PM

It still makes the noise in 4hi and it doesn't make the noise if the transfer case is in neutral. The noise is constant if I'm moving around 35+mph and the transmission is in neutral or the clutch is pushed in. I only have the rear driveshaft on at the moment. It will make the noise in a higher gear going over 35 and I just barely give it throttle but if I let off completely it stops or if I give it throttle to accelerate it stops.

**vegas TJ driver** · 08-18-2012, 11:37 PM

Rear ring & pinion?

**tjsean0308** · 08-19-2012, 02:04 AM

how many miles are on the transmission? I'm not sure how loud this noise is for you. But I noticed that my input bearing on my AX5 has some play and was seeping oil ever so slightly when I did the clutch last year at 168,000 or so miles. I have a slight bearing noise that is apparent idling in neutral clutch engaged (pedal released) once I disengage the clutch (press the pedal) and select a gear to stop the input shaft or let it coast down, the noise disappears. So that tells me input shaft bearing. I know I am on borrowed time, but this might be something for you to pay attention to depending on the age of your transmission.
To further isolate you could in a safe controlled environment think big as empty parking lot. Get it to up to 25 put the trans in neutral and click the key off one click being careful not to lock the steering, let the clutch out to stop the input shaft with the trans in neutral, so the truck will coast. that would rule out my suggestion if the noise persists. also with the engine noise out of the picture you might hear something different that clarifies the issue.

nastyzj · 08-19-2012, 02:09 AM

id say its most likeley the transmission pilot baring or the throwout baring

jeepercreeper13 · 08-19-2012, 09:06 PM

Thanks guys, the noise is very loud but is hard to pinpoint exactly where it's coming from. The sound travels down the driveline from the bell housing to the rear driveshaft. I know its not in the rear, the noise started with the d35 and last Saturday I swapped in my 8.8 and I still have the same noise. My transmission has around 132000 miles on it. I'm going to be pulling out the transfer case here soon to put the sye in and while I'm at it I'm gonna pull the tranny and check everything out.

**tjsean0308** · 08-20-2012, 01:45 AM

sounds like a plan let us know what you find.

CaposgrayTJ · 08-20-2012, 07:51 PM

BUMP.. I'm experiencing the exact same problem with my 6 speed....

jeepercreeper13 · 08-20-2012, 08:51 PM

Got the transfer case torn apart tonight and everything was fine there. I'm going to pull the transmission later this week. I'll let you know what I find

jeepercreeper13 · 08-21-2012, 07:54 PM

I decided to pull out the tranny tonight and found that the pilot bearing was all dried up

**55willystruck** · 08-21-2012, 08:12 PM

Quote:

Originally Posted by CaposgrayTJ

BUMP.. I'm experiencing the exact same problem with my 6 speed....

This is my problem as well. Pilot should squeal correct as its bushing not bearing? Thinking throw out instead??? Thoughts???

Best of luck,

Mike

jeepercreeper13 · 08-21-2012, 09:50 PM

My throwout bearing was fine but the pilot bearing (which is a needle roller type bearing that's pressed into the rear of the crankshaft) was all dried up.

**tjsean0308** · 08-24-2012, 04:02 AM

This was what my throwout bearing sounded like on a cold morning. I could play music with my boot. don't mind the terrible video quality its all about the sound.

The pilot bearing was fine this was all frozen throwout bearing. I didn't notice the bearing noise until after I did the clutch.

**55willystruck** · 08-24-2012, 07:21 AM

Quote:

Originally Posted by tjsean0308

This was what my throwout bearing sounded like on a cold morning. I could play music with my boot. don't mind the terrible video quality its all about the sound.

The pilot bearing was fine this was all frozen throwout bearing. I didn't notice the bearing noise until after I did the clutch.

By chance did you have a loud growl as well-gravel in coffee can sound just BARELY on the throttle? As in-very light foot pressure on throttle with growl, more and sound gone. On the gas, no sound, then let off and just at that point before foot is off the pedal, growl is back? Your opera singer there is something that comes and goes almost exactly on mine-up to around 35-40mph before wind noise cancels it out. The growl does as well. Fairly certain this is the issue, just looking for a definite. As long as the rig has been down now and only been on the road again here within the last couple weeks, not real thrilled about taking it down already-again.

Thanks,

Best of Luck,

Mike