OK well first off I have never owned a jeep before and my wife needed a good vehicle for the winter time to drive around. She set her sights on a 1999 grand cherokee V8 with 150K miles on it. Now I am a mechanic myself for the army so I looked it over and drove it around and everything seemed fine so I got it for her. Well one day when I was home on leave I let off the gas to coast to a stop sign and i herd a loud metallic like tinging sound in the front end. I also felt a lot of vibration underneeth me but you could tell it was in the front end somewhere. the noise stoped when I stoped and you don't hear it on acceleration. I poped the hood and I noticed the fan clutch was bad because it had about 4 inches of play in it so i thought maybe that was the issue. I replaced it and went on with my way and it stoped making the noise. well yesterday I got a call from my wife saying it is doing it again but this time it is louder. still only on deceleration. I am not to sure how this all time 4 wheel drive works but with my past expieriences I know that if a U-joint is bad it can cause this vibration or it could be something inside the differental carrier. this vehicle has normal street tires and from what I have seen no modifications done to it. Has anyone else had this issue before? Any sugestions? I am planned on going back home this comeing weekend to look more into it but if anyone has some sugestions to look at first or something you know that could be the cause of this issue? Thank you for reading this and any help you can give me.

 

The front driveshaft cv joints are a common issue of your symptoms.

 

Are you refering to the half shaft CV joints in the front axle or are you menaing the U-Joints in the driveshaft?

 

Dont wanna hi-jack the thread, but the reminded me of hearing a noise just like you describe. Metallic tinging together, or something. But no vibrations and coming from the back. Any ideas?

 

Did you verify you have ujoints? Some have the CV and are a known common problem.

 

look up pinion gear problems imo

 

Ya I went home and test drove it and it took it a while for it to start doing it with me. But when I got it to do it man did it sound bad. You can hear the spider gears in the front diff chattering like there is no tomm. I only had two days home so her dad is going to take it to his friends shop to replace the diff I guess. I don't know if there is shims inbetween the spider gears and the carrier but i know when I pulled the cover off of it when it was cold there was no end play between the gears and absolutely no backlash anywhere in the carrier. My guess is that when the gears heated up and the metal expanded thats what made the gap between the gears even less and they are binding bad. The gears really didn't look bad but you could tell they had gotten hot. They have a blueish tent to them and the gear oil smeled a little on the burnt side. I noticed that the drivers side cv axle had been replaced and I was wondering if maybe when they slide it back into the differential the splines may have been moved to far over causing the spider gear to have more tention with the other gears in there and that is the noise we are hearing. Anyone got any ideas on how much a diff costs? or if the carrier isent damaged if you can just buy the internals? Thank you all for all the input it really helped me nerrow down what the causes could be and saved me a lot of time!!!!

 

i had my rear differtential rebuilt a few weeks ago, it cost me about $1300