Problems with the xj

#1
So when I had my dana 30 and 8.25, i had no problem. As soon as i swapped the waggy 44s with the 4.10's i knew the gears where worn. So i took the jeep to Hartsville 4x4 and had the gears installed front and rear with new 4.88s. So I had maybe put 300 miles on the jeep since it has been back and it is making a really high pitch wining noise. I know he replaced some of the bearings and such in the axles also while it was up there. However the jeep seams’ almost like it slips every now and then, one every week or sometimes twice. It feels like it spools up but let’s go. It sound as it is coming from the rear of the jeep. I am lost i need help trying to figure out when to look for. Sometimes it will wine around 30-45 mph. It’s almost like a humming sound. What should I look for?

Some people have said Power steering or pulleys, but that is not the case
Pinion bearing? or is this replaced when gears are?
Could it be the T case?
U joints in the drive shaft?
Trans?

My plan is to replace the transmission filter, and fluid. Change rear end fluid, and t case fluid! For the start
But after this I’m lost as where to look!
 
#2
Get the tail end up on jack stands, and have someone spin it up to the speed in which the noise occurs. Then you can listen for the noise while under the vehicle. It could be bearings, or the backlash could be off. Find out what all was changed with your gear swap, and work back from there. You might consider taking it back to the shop, and let them have a look. If they messed anything up, they should get a chance to make things right. I wouldn't wait too long, they can't be expected to fix any further damage from putting it off.
 
#3
x2 on what nota said about the rear end. Did the guy use master install kits or partials? Did the wheel bearings get repaved on the shafts? I assume you are running around with the hubs unlocked so the noise is isolated in the rear. Well you're supposed to change the diff fluid at 500 miles after a gear swap anyhow, but remember to pay close attention to the fluid for flakes of metal or an excessive silver tint to the gear oil. You can run a magnet through your catch pan if you aren't running magnetic fill plugs. Do you know what brand gears or install kits that Lenny used?

Now the slipping thing sounds like the tranny. Does it do it in a particular gear or shifting from one gear to the other?
 
#4
Its up on stands right now! Im going to look at it when I get off tomorrow. I know the pinion angle sucks on the rear axle and its binding up the drive shaft but it has been doing that for the last 6 months so I am going to buy new brackets.

I got the gears from rons machine shop lenny deals with them alot. They are yukon gears and master install kits. I really dont think its the gears since no one has had any complaints about lenny. I am going to give him a call tomorrow though so I can see if he can help walk me through this process!
 
#5
Driveshaft bind usually only acts up on acceleration or letting off of the gas. I know my old 96 xj rear shaft bound up at the tease end when I let off of the gas. Ended up fixing it with a SYE, CV shaft, and new leaf mounts a few weeks later. Also if the shaft was bound due to bad angles it would quickly kill the u joint and/or cv joint would would give you the chirping bird sound from the u joint or crazy vibes from a bad cv.

If you do go the new leaf perch route you might want to look at TNT u bolt eliminators. I ran a set on my black 97 xj and they are super cool as you have three or different centering pin holes and you can also buy them with lift built into the mount so you dont have to run huge shackles or what not.
 
#7
if your redoing your brackets and you dont go with the ubolt eliminators I would suggest the antirap perches from ruffstuff I think it is. They have some 8" long perches that all but eliminate axle wrap and they have different centerpin holes for stretching the rear an inch.
 

LBarr2002

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#8
if your redoing your brackets and you dont go with the ubolt eliminators I would suggest the antirap perches from ruffstuff I think it is. They have some 8" long perches that all but eliminate axle wrap and they have different centerpin holes for stretching the rear an inch.
Agree. I used those on the Explorer and it didn't wrap at all. I actually used the extra holes to move the axle an inch forward so I didn't have to get a longer driveshaft with the spring over lift :).
 
#11
Well I started this morning by going to the parts store! I have been running amsoil 75-90, I pulled the diffcover off drained it looked really good no shavings ext.. I put in some coastal 85-90. I also got a new 44 diffcover which has the plug at the top instead of the bottom like my old one did which didnt hold the recomened amount of fluid. I am still lost though. It was really bad with the 4.10s and when the 4.88s went in their was no noise 300 miles later their is noise. It is really here and their now. It makes the noise every 10 or so miles and then stops after a min or two. I am really stumped. I have been listening to it and it sounds more and more like its coming from the trans. The gears are not worn and no shavings!
 
#12
well it could be the trans but are you expieranceing any shifting issues? Have you checked the fluid in the trans and/or dropped the trans pan? Are you running a SYE? I know I expieranced some weird on and off noise from the rear of my 97 XJ, but it ended up being bad calipers from when i did my junk yard zj disc brake swap onto the 8.25. Seems the calipers weren't disengaging enough and the pads would slightly drag every once and awhile.
 
#13
Like I was saying over the phone, double check and make sure you're using the correct fluid in the trans. I can't think of the exact formula off the top of my head. DEX3 or something.
 
#14
well it could be the trans but are you expieranceing any shifting issues? Have you checked the fluid in the trans and/or dropped the trans pan? Are you running a SYE? I know I expieranced some weird on and off noise from the rear of my 97 XJ, but it ended up being bad calipers from when i did my junk yard zj disc brake swap onto the 8.25. Seems the calipers weren't disengaging enough and the pads would slightly drag every once and awhile.
I used to own it and the trans was serviced about 5-6k miles before he bought it and it does have a SYE/ds installed. Now how many miles he's gone since then or if anything's been changed I dunno.
 
#15
Well I am swaping out the rear purches for anti wrap, and giving the drive shaft a better angle. I have the pan off the trans right now checking the fluid and bands and trying to see if i can get to the sensor that needs replaced. I will be putting some new u joints in the Drive shaft next week and go from their!
 
#16
So now that i am servicing the transmission i really want to drain all the fluid TC included. I see alot of guys say to drain refill drain refill drain refill, but that is alot of waisted fluid. Is their a better way?

Also alot of people go back and forth on what fluid is correct I have seen atf+4 and dex mar III, some say the friction mod in the dex mar is not good! However I thought that dex mar III was the right fluid!
 
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