mexicoboy68

The rear axle on my 1999 4.0l Orvis makes a rumble/knocking noise when pulling away. This only happens for about 10 seconds then dissappears. I am thinking the rear diff is needing overhauld. Has anyone done this repair? I believe a special tool is required to spread the axle housing to remove diff.

Fruid

Mine does exactly the same thing, it's always done it since I have owned it and it has never got any worse.
I am just going to leave it for that reason
Is yours a Dana 35?
Must be a Scottish thing

weebur

To remove/replace carrier assemblies most require an axle spreader (expensive) to do the job correctly. But sometimes you can get lucky by tapping it in with a BF dead blow hammer. This is what I do to troubleshoot gear noise and the condition of the spider/side gears and the shaft that runs through the carrier:

Gear Noise
What I've done several times on different vehicles is to get the rear wheels off the ground/on jack stands/cover off/idling in the lowest gear.

If the carrier bearings are toast you should be able to (carefully) put your hand on the bearing caps and feel and listen for a grinding/growling. Using a stethoscope near the rear backing plates on the axle tube you should be able to hear the same sounds from the wheel bearings (leave the wheels/tires on to put some load on the wheel bearings).

The sounds will be much less than when you're driving because they're not under much load, but you should be able hear really bad bearings. Doing this shouldn't damage your gears/bearings providing that its at low speed and for only a very short time. Also, shake the rear pinion yoke in/out/side to side; there should be no movement at all. Is your pinion seal leaking?

Optional: There should be slight movement between the ring and pinion gears before they engage, it's called backlash and you should check it with a dial indicator. You should also get some special grease and coat both sides of the ring gear surfaces (6 or so teeth) then rotate the assembly back and forth several times to check for the contact patterns.

Another way to check for bad wheel bearings is to make hard slow speed turns. This will unload one side and load the other. The sound should shift from one side to the other while doing this.

I would start by checking your rear u-joints first.

Fruid

I have looked into this particular noise that we are both getting, basically the only noise I/we get is a soft binding/rumble as you pull away from a total stop and more so if its in a turn and more so again if you are pulling a trailer/boat.
Once the Jeep is moving it is as quiet as a mouse, I have just done a 1000mile return trip to the South of England in mine and no noise at all on the motorway just from manouvering in the service stations.
Personally I think it is the LSD clutch plates in the diff either worn or damaged, I don't have the expertise or the will to attempt to remove them so I am just leaving it be until it gets much worse.

00jeepXJ

Honestly it sounds like your pinion is going out. I would look at your u joints also. The u joints your able to do in your yard with a big hammer, a chunk of wood ( a 2 in x 4 in ) and two sockets your not to worried about. To check the pinion pull the drive shaft with the rear axle jacked up in the air and properly blocked, and spin the pinion. You could do the pinion bearings at home if you had the tools and desire to or just take it to a shop and have them do it.

jtm01xj

I have the same problem on my 2001 Cherokee xj and I thought the same thing about the rear end but as I was checking everything out I noticed that my transmission Mount was worn out so replaced it and the shutter at take off went away

Fruid

I actually took my rear prop shaft off and was about to change the UJ's but they were in perfect shape so I just greased the slip yoke and put it back on.
Which part is the pinion? I assume its the large cog visible once the cover plate is removed.

cruiser54

Check to see if your exhaust is grounding out on the trans crossmember due to failing engine/trans mounts. very common.

00jeepXJ

Pinion is the gear that the drive shaft to the axle. You can check it. With the drive shaft ( prop shaft ) off grab hold of the yoke and see if it has a large amount of movement. Rotational movement should be minimumal to none. You are not wanting sideways play or in and out.

jake92

What is happening when there is a whining/howling sound the increases/decreases in relation to vehicle speed and accelerator use

00jeepXJ

General location of the noise? It could be a bearing. Though I would guess that it would be the carrier bearings for one of your differentials. Most times its the rear end. They have to be pressed off and the new ones pressed on. Removing and installing the carrier from the differential is something that you can do. Keep the parts for each side separate and clean, while noting location and position of the caps and the shims. The carrier may need some "encouragement" to come out with a piece of wood to help pop it out. Install the same way it came apart.

jake92

From the rear end. I just recently finished a manual drive trains and transaxles class at the school I'm going to automotive for so rebuilding a rear end doesn't scare me as much as it did lol. Now if it is the carrier bearing what are the possible consequences? Broken axle?

00jeepXJ

Destruction of the rear end. Kinda like how if you ignore a wheel bearing too long your wheel can fall off. You can drive it a little while but I wouldn't rely on it too much. If you have access to the tools at school the teacher should be willing to use you as an example in class and you get to work on your jeep.

mexicoboy68

Thanks guys. I will look at the various suggestions. I did forget to say,when i carried out last service,i replaced the diff oil ans added mopar additive. The noise dissappeared for about a month and then gradually came back. This makes me think it might be the friction plates within the diff.

Aljay

I would not waste any $$$ on the axle if its a D35 I rebuilt the D35 in mine and regret spending the money now. should have swapped the axle out to something else. I am now gathering parts for an 8.8 swap . picked up complete 8.8 yesterday for 53 bucks 3.55 open. I will put in an aussie locker and party on.