Well I posted about this before but long story short... The CRD might have been making the sound all along, but since I changed all the fluids I just started noticing it. I only notice it around 40-50mph and the only thing I can think of it might be that I need heavier weight real end oil. When I changed the rear end fluid I used Mobil 1 75w90, maybe I should try the 75w140 and some different friction modifier?

Well I touched the rear end cover right after a 20 mile drive home and it was warm. Not sure how warm but it was warm to the touch and the undercoat that is on it was soft. I have a bad feeling something is wrong. What could it be, I put the right stuff in it when I replaced the fluid. Do you think the friction modifier might have messed something up, I didn't use the Chrysler stuff, I used some stuff from Murrays auto parts. Should I expect somthing to be wrong, or should I just replace the fluid again and add some of the Chrysler additive that I got?

I'll take my IR temp gun with me next time I go out and check how it is and maybe someone on here might be able to do the same with your jeep so I can compare temps. Thanks..

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-05 Dark Khaki Limited CRD. GDE ECO tune. In-tank lift pump, Transgo doo doo kit, B&M trans cooler, replaced trans solenoid pack and filters, Newer Michelin tires, Timing belt with all related parts replaced at 110,000miles.

How did the gear oil look when you drained it? Was it full of metal particals? Some is okay but when the fluid looks like glitter that is very bad.Try moving the yoke,if it moves up/down or side to side that's not good(pinion bearings shot),also jack up the rear end and try moving the wheel up/down and side to side,if you can then that axle bearing is shot,easy fix but you may need to replace the axle also.Is the noise more heard on acceleration? Or deceleration? If either of those the gears are not setup properly.Or does it make the noise when turning? Have the trac-lok(assuming you do if you need friction modifier)? Might confirm you actually have the trac-lok and if you do you need the correct amount of friction modifier which is 4oz.If you do have the trac-lok and you have added the correct amount of friction modifier the trac-lok could be wearing out.Doubt running 75w90 gear oil has caused the noise but it couldn't hurt to switch to 75w-140 but there still shouldn't be a noise regardless.

The old gear oil looked ok and the magnet wasn't caked any more then normal. I'll try to check the play in the wheel, and it is only heard on acceleration. When you let off the accelerator the noise stops, when it up shifts it noise is unaffected so that leads me to believe that the problem isnt in the engine or trans and really is in the rear somewhere. I don't think it would be the TC but who knows. I don't think it has the trac-lok because I lifted it and in gear the wheels spin opposite of each other, in neutral they only one will spin when spun by hand. Thanks for the info man.

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-05 Dark Khaki Limited CRD. GDE ECO tune. In-tank lift pump, Transgo doo doo kit, B&M trans cooler, replaced trans solenoid pack and filters, Newer Michelin tires, Timing belt with all related parts replaced at 110,000miles.

Well yesterday after a long drive I pulled over and stopped by down shifting and checked the temp of the brakes. The RR was was cool the same as the others, but then later that after some brake applies I checked the RR and it was HOT like 760F compared to the LR at about 155F. SO Obviously I have a bad caliper, but do you think if it has been sticking on and off over a period of time it could have led to this sound I'm hearing? After I noticed the RR getting very hot I did a little driving and pulled over with out using the brakes and clamped off the brake like going to the RR. The RR was cool now and ofcourse the sound is still there. Now I wonder if the brake locking up lead to this darn sound. This is a pain.

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-05 Dark Khaki Limited CRD. GDE ECO tune. In-tank lift pump, Transgo doo doo kit, B&M trans cooler, replaced trans solenoid pack and filters, Newer Michelin tires, Timing belt with all related parts replaced at 110,000miles.

Another think to check is the drive shaft ujoints. I had one freeze up and caused a nasty whine. Brake caliper is a common problem. Mine went bad at 37k. haven't had a problem since I replaced it. 71k

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2005 CRD "Ol' Blue"
Red Ryder carbine-action, two hundred shot range model air rifle with a compass in the stock and this thing which tells time.
My build page- RL Komodo Rear and TJM Front Bumper, armored, lifted, JBA Steel D30, 4.10s and ARB air lockers.

I replaced both rear calipers and linings, also replaced the diff lube with 75W140 and it didn't seem the have any effect on the noise. Thinking either the pinion bearing or wheel bearing maybe? Pain in the rump.

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-05 Dark Khaki Limited CRD. GDE ECO tune. In-tank lift pump, Transgo doo doo kit, B&M trans cooler, replaced trans solenoid pack and filters, Newer Michelin tires, Timing belt with all related parts replaced at 110,000miles.

i have the same whine/hum, had it for a while. I think it is the pinion bearing as well. I'm looking just replacing the entire rear axle as it will be cheaper than having a $15 part replaced +$600 labor.

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L.O.S.T. #225019
2003 Sport 4x4
Patriot Blue w/ trail rash
Flex-Zilla 4" Lift
TrailRash hi-lift mounts
Other stuff you wish you had