Need help diagnosing noise

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Sep 29, 2016 | 07:01 AM

xtamer

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Joined: Dec 2012

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From: Hell

Need help diagnosing noise

02 f250 SD 5.4 zf6 manual xcase ext cab long bed
When I'm cruising down the highway it's most noticeable. 5th gear anywhere from 65mph+ I'll let off the gas and it'll make a "errrRRRt" until I press the gas again.
I've recently installed new-
Front u joints, ball joints, hub assemblies, rotors, calipers, pads
Rear drive shaft u joints
Front diff fluid
Trans fluid
Tcase fluid
4" zone lift kit

All of these things did nothing to effect the noise. it seems to be coming from between the clutch and rear shaft (either clutch, trans, tcase).
I don't think it is a motor noise or suspension noise. Any input is appreciated

Sep 29, 2016 | 08:56 AM

Boaterguy

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Joined: Oct 2014

Posts: 962

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From: Middle TN

How many miles on the truck? I don't know if this helps but, back in the day when I had a 1995 F250, I developed the same noise around 150k. At speed, every time I would let off the gas I would hear a loud howl or groan from under the truck. Get on the pedal, it goes away. It turned out to be an issue with the rear differential. Had a Trans shop rebuild and it went away. Might want to run it by a transmission shop and let them hear it.

Sep 29, 2016 | 10:13 AM

xtamer

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From: Hell

It's at 150k too. Has 4.10 gears. And the rear diff is the next on my list to service too

Sep 29, 2016 | 10:44 AM

Boaterguy

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Joined: Oct 2014

Posts: 962

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From: Middle TN

Yes, my '95 had the 4.10 gears and limited slip. If yours has a drain plug, it would be better to remove the cover and look inside. My gears were worn out causing the noise. Just a thought here since I have never lifted a truck other than a levening kit, but I have heard from some of my friends who like to jack their trucks 6' in the air that they have to have the driveshaft lengthened to prevent stress and wear on the u joints. Not sure if that would apply in your case but could also be a source of noise........Good luck.

Sep 29, 2016 | 11:06 AM

xtamer

Thread Starter

Junior User

Joined: Dec 2012

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From: Hell

The place I got the kit from is pretty reputable and said I wouldn't need a carrier bearing drop or anything, not saying I don't but I don't think I do. I'm gunna check rear diff and see what it's like in there.

Sep 29, 2016 | 11:21 AM

Boaterguy

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Joined: Oct 2014

Posts: 962

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From: Middle TN

Post back when you can. I would like to know what you found in there.

Sep 29, 2016 | 01:31 PM

don123

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Joined: May 2006

Posts: 1,047

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From: Massachusetts

It could be the pinion bearings. My old f150 would make a loud growling noise only when I would let off the gas and stop as soon as I gave it gas. I tore the rearend apart and the pinion bearings were shot. While I had it apart I replaced the carrier bearings,wheel bearings,and clutch packs for the LS.