98cherokee531

Running a 95 Cherokee, auto with a 242 t-case. It has been lifted 4" for about 1 year now. 1" t-case drop and a 4* pinion shim and I had 0 vibration no matter the speed or rpm. Yesterday cruising the highway around 65 I started getting an unusual hum. Then in high gear (overdrive if you will) the rear end starts to shake when the throttle is applied. Back off the throttle or shift into 3rd manually and it goes away. I changed both rear u joints last night as a precaution. Brought her to work this morning and we are still shaking in high gear. I found no play in the pinion bearing at the rear axle and the transfer case output shaft seems to be tight as well. Any ideas?

TRCM

are you sure it's the rearend, and not the transmission mount ??

98cherokee531

I checked the trans mount and it didn't seem like anything out of the ordinary. I guess it wouldn't hurt to go ahead and change it out.

TRCM

Not always easy to tell if the trans mount is bad by looking

Can you power brake it and feel the trans move ?? or any kind of thump when you get on or off of it ?

Cane

i have no play at my pinion bearing but it still makes a humming sound on deceleration at certain speeds, so i wouldn't rule it out completely only because it's not loose.

also is the slip yoke at the rear driveshaft greased well? transfer case output shaft is solid?

98cherokee531

this is going to sound dumb but on my way home today it didn't act funny. But at the stop light I noticed a small faint low rpm misfire. Not all the time. I'm thinking it was a low rpm (in overdrive) misfire that was causing the driveline to shake. I'm going to do some quick routine maintenance on it and see if that clears anything up. Thank you for the suggestions

98cherokee531

yes all is greased and the output shaft doesn't seem to have any play when moved by hand. I think it's a low rpm misfire that shakes the driveline when it's in overdrive. I'm going to do some maintainence and see what happens

JHONEYCUTTXJ

I just recently purchased a 97 Cherokee and I'm having the same issue. usually around 45mph only when the vehicle is in final drive at RPM's lower than 2k. Any updates if it was a missfire? Or what it took to fix it?