• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

trans/transfer case noise

S

StevieRT

NAXJA Forum User
Location
West Chicago, IL
I got a 98 4.0/AW4/231 and I have this weird clunking/ pop noise when I go from D to R or vice versa. Then when I am driving forward I can hear this squeaking kind of noise up until about 30 mph or so. It sounds like U-joints but they seem to be totally fine. I am stumped and cant seem to turn up aything from searching. The Jeep still works totally fine though, it shifts through all the gears great and the 4wd works too. Thanks for any help.
 
So, with an external tach measure the idle speed of the engine AFTER 20 minutes of driving, transmission in DRIVE, parking brake set and the foot of a friend pushing on the service brake pedal.

Idle should be 700~750 RPM. Post up what you find.
 
StevieRT said:
I got a 98 4.0/AW4/231 and I have this weird clunking/ pop noise when I go from D to R or vice versa. Then when I am driving forward I can hear this squeaking kind of noise up until about 30 mph or so. It sounds like U-joints but they seem to be totally fine. I am stumped and cant seem to turn up aything from searching. The Jeep still works totally fine though, it shifts through all the gears great and the 4wd works too. Thanks for any help.
Click to expand...

still sounds like a u-joint-- they can "dry out" and squeak without extra play. Rest assured, they won't last long once it happens, though

joe_peters said:
So, with an external tach measure the idle speed of the engine AFTER 20 minutes of driving, transmission in DRIVE, parking brake set and the foot of a friend pushing on the service brake pedal.

Idle should be 700~750 RPM. Post up what you find.
Click to expand...

misplaced post?? or help me understand your questioning....
 
I dont have an external tach but I am just making sure this post was for me...? The Jeep tach seems to be right on the money but what were you thinking if it wasn't?
 
Idle speed way to fast, when you shift it "slams" into gear.
 
So it still could be u joints even if there is no play in them? This clunking/popping noise seems somewhat too severe and sounds like it is coming from the trans/transfer case itself rather than the joints. I know these problems are almost impossible to diagnose over the internet without seeing or hearing the Jeep in person.... Thanks though, I should probably start with the joints first though since they are cheapest and somewhat easiest to replace......damn Chicago winters and rust.....
 
Shorty said:
gotcha on the D to R noise-- shouldn't give you a squeaking noise, though.
Click to expand...

Yeah, figured he might have more than one thing going on.

Squeaking noise present when backing up? Might have some crap in the caliper rubbing on a disc.

Check the u-joints with a bright spotlight, the DS and axle, see if there appears to be any rust dust escaping from the caps.
 
Another place you can get a clunk is where the exhaust pipe goes above the trans crossmember. Bad trans mount can cause that. Come to think of it, I'd take a look at the trans mount. Looks like you've got your work cut out for you. Get off the computer and head out under the Jeep with a flashlight.
 
don't forget to check the pinion for play as well. My money would still be on a nasty u joint, even if they look ok.
 
Thanks guys for all the help. I couldn't tell until I took it all apart but it was a bad front ujoint on the rear shaft. It was all dried out and hard to move but not loose or anything, it was kinda hard to believe it made all that noise, but its fixed now. Thank God it was just a u-joint, I was starting to get really worried with the noises it was making....
 
You must log in or register to reply here.

Similar threads

M
4X4 grinding from 4H to 2H
Replies
6
Views
2K
techno1154
techno1154
Saudade
Speedo Deado
Replies
4
Views
2K
Anak
Anak
A
Grinding noise on initial 1st/2nd shift
Replies
4
Views
1K
aquaman788
A
G
Loud Clunking noise when turning.
Replies
0
Views
99
gverrilli
G
N
AW4 trans sensor problems
Replies
8
Views
942
News09
N
Back
Top