Front Diff / Driveshaft Problem

Brucey69

Brucey69

New Member
Joined
Apr 13, 2022
Messages
15
Location
Stockton, NSW
Hey guys,

Newer member from Newcastle, Australia. This is my first Jeep, 2001 TJ 4.0 Auto, 195,000kms, have had it for almost a year and have been replacing stuff as I've needed to...

Now, I've got an issue with my front diff / driveshaft and wanted to post some photos on here and describe some of the issues I've been having to get some opinions and help fixing these. Recently, I've had a clicking / scraping sound (I've also heard of angry bird sound or something??) as I initially accelerate and when I am braking coming to a stop. My "general" mechanic (I say general because he is not a Jeep expert) said I've got play in the driveshaft going into the front diff, and it is leaking (as you can see in the photos), and he suggested I take it to a gearbox/diff mechanic. I am mechanically inclined, but I haven't dealt with or done any diff/driveshaft work before, and I don't have a lift or anything like that so I am restricted to doing everything on the ground unless I absolutely have to go and get a jack and some stands. I spoke to the diff and gearbox shop here and they thought based on the above description of noises/play in the driveshaft, it would be a $1100 diff rebuild. So, before I go and fork that out, I have a couple of questions...

1. Just looking at the photos and the video, any ideas on if I'd have to get the whole thing rebuilt, or is is a pinion seal/bearing issue? I've read some posts about pinion seals, centering yokes, etc etc, which I don't have a whole lot of knowledge about, so any info on what that process looks like would be awesome.

2. To prevent any further damage, can I take off the front driveshaft and run 2WD until I get this fixed? If so, can someone point me in the direction of a how-to to get the front driveshaft off?

Any other comments or help resolving this would be awesome. Thanks guys!

Diff 1.jpg


Diff 2.jpg
 

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Could be bad U joints and bad pinion bearing. Taking the front drive shaft off isn’t too bad. The bolts on the front yoke are like 8mm heads and there are four of them. You can just take the front off of the yoke attached to the front diff and tie it up, or you can take the rear off that attach to the transfer case. You might have to drop the skid plate to get to them. I took mine off when I had my floor pan cut out so I had easy access. Once you remove the straps that hold the u joints to the yokes you can pop them out with a screwdriver or pry bar.
 
Might check the fluid level in the front diff. Hopefully just U joint making noise and the pumpkin is not dry. had simular issue. Jeep would make intermittent high pitch sqeaking and figured out the lil needles in the ujoint caps where smoked and was easy fix. If your going pull the drive line make sure you soak em down in penetrating oil and break em loose slowly. If they have not been off in a long time they will snap off in the yoke and there a PITA to drill and extract. taking the front off is pretty easy but on the tcase end you need a pretty short 8mm socket on a 1/4 drive. Every time i have tried to break tcase end loose will a box wrench it strips so i wouldn't advise that. Hope that helps ya.
 
UPDATE: Got the front driveshaft off and tied it up and went for a test drive. Noise was still there, and I also noticed shifting into Drive (AUTO) was a big clunk. Not sure if it was more prominent now that I was looking out for noises, but it was loud shifting from N into D.

Took a video as I drove with the sound, the link is below. It almost seems its coming from the back or middle now when I initially thought it was the front because of the leak coming from the front diff. Rear driveshaft has zero play, but now thinking it could be a transmission issue? Is the sound in the video familiar to anyone?

Clicking Noise @ rear
 
Disconnecting the front driveshaft is part of the usual troubleshooting a noise such as what you are experiencing.
The clunk can be indicative of a U joint that is going bad when applying torque to the driveshaft in DRIVE.
I would do a thorough inspection of the rear driveshaft U joints where the cups slide onto the trunions (pivot point) lookinbg for rusty dust coming from where the cup slides onto the pivot point and excessive play in the U joint.
Removing the rear driveshaft is much easier than the front driveshaft since the driveshaft just slides out of the transfercase end.
The U joints can be replaced with a vice the hold the driveshaft, a couple sockets, a ball pean hammer, a small screw driver and needle nose pliers.
 
tbruce11 said:
UPDATE: Got the front driveshaft off and tied it up and went for a test drive. Noise was still there, and I also noticed shifting into Drive (AUTO) was a big clunk. Not sure if it was more prominent now that I was looking out for noises, but it was loud shifting from N into D.
Click to expand...

Maybe jack up the rear axle (on to jackstands) and have someone put it in drive while you look and listen.
Just because the front shaft is out, don't rule out the front axle u-joints.
 
LONGJP2 said:
Maybe jack up the rear axle (on to jackstands) and have someone put it in drive while you look and listen.
Just because the front shaft is out, don't rule out the front axle u-joints.
Click to expand...

Yeah, I plan on grabbing a few tools, some penetrating spray and I am going to get at least the rear axle off today to get those u-joints out and see if I can find the culprit there. I’ll get the front fully off as well after that. The rear u-joints look pretty toasted just on visual inspection… will update once I get those off.
 
So some good news, and some better news I suppose, so far...

I got the rear driveshaft off. One of the u-joints is gooooone, and I believe its my culprit. One side of it is very loose, and the grease insert is actually gone from it, there was just a hole there. The other u-joint had the grease gun feeder and looked fine. I haven't taken the u-joints out, hardware store isn't open yet for me to grab a couple tools I need to get those apart.

The other good news (kinda, maybe?) is that when I got the rear driveshaft out, I noticed some very shitty, dodgy home welding job to repair the yoke(?). Looks like whoever did it welded the yoke to make sure the clip stayed in. I've never repaired or done any drivetrain work before, but my guess is that isn't normal, so it's good news that I found that.

Thanks everyone for the help as always. Love these forums for that. Will provide update once everything is purchased, arrives and is installed.

Rear Driveshaft u-joint 2.jpg


Rear Driveshaft u-joint.jpg
 
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Might want to think about replacing them all while you have everything out. The others won't be but so far behind.

Edit: And if you're pulling the front axles, might as well get at the axle and pinion seals. Hubs and rotors wouldn't be a bad idear. Bushings all around, of course. Since you're doing hubs and rotors you don't want to ignore the rear brakes. And rear axle & pinion seals.

That's what happened to me, just wanted to spread the joy.
 
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Is the part that is (crappy) welded called the driveshaft end yoke? Does anyone know the exact part number for a direct replacement if so?
 
DEValken said:
Might want to think about replacing them all while you have everything out. The others won't be but so far behind.

Edit: And if you're pulling the front axles, might as well get at the axle and pinion seals. Hubs and rotors wouldn't be a bad idear. Bushings all around, of course. Since you're doing hubs and rotors you don't want to ignore the rear brakes. And rear axle & pinion seals.

That's what happened to me, just wanted to spread the joy.
Click to expand...

Cool cool, thanks! I did the rear brake shoes, rear axle seals and wheel bearings as I had a leak and thought that might have been the issue initially.
 
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tbruce11 said:
Is the part that is (crappy) welded called the driveshaft end yoke? Does anyone know the exact part number for a direct replacement if so?
Click to expand...

that's the top end slip fitting yes? so that would be the transfer case output yoke, if i'm not mistaken.
google that spicer # it' should bring up something. they broke the snap ring groove and jimmy rigged it.
 
You can get a factory style rear driveshaft for pretty cheap on eBay. I’ve bought one on there for $40-$50 bucks before for a spare and it worked out fine for me.
 
pagrey said:
I think Crown Automotive 4882714 works, I don't know what parts are easy to source where your are.
Click to expand...

I was able to order this part from Amazon US, just shitty shipping price trying to get it here quicker lol. Hopefully will be here at the end of next week. Thanks for the recommendation!
 
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