burg3rlicious

Specs; 98 Cherokee 4.5 inch adjustable short arm lift, poly bushings, sye and cv driveshaft w/shims, stock d30 and c8.25 adjustable trackbar. Lifted for about year now.

I went to replace my u-joints the other day only to find out the ears/yokes were ruined and had to replace the shafts as well. I ended up getting used shafts from the JY and had "confirmation" that the u-joints were good, they were a bit dirty and rusty but nothing that led me to believe they were necessarily bad. I popped the new shafts in and replaced the hubs while I was at it. For 2 or 3 days everything was dandy but starting this morning I've been getting some weird noises I frankly can't diagnose. I was getting some squeaking upon acceleration which I'm attributing to my new hubs breaking in? The second is a popping when accelerating from a stop, but its gradual meaning the increment of the noise is directly related to how much gas I'm applying. The reason I'm not directly diagnosing this to u-joints is because typically when u-joints are bad you can hear popping while braking (which I don't) and when turning (which I don't), not exclusively acceleration right? The third is just that my jeep is louder the more I accelerate, like droning loud when when you run big mud tires and have an unbalanced driveshaft. All of these noises do not occur when the car is in neutral. The motor sounds fine revving all the way up to redline, these sounds only occur under load with the exception of the squeaking.
These are my thoughts based on looking around the forums:
1. Got ****ty u-joints in the used shafts
2. Bad motor mounts/tranny mounts that coincidentally went bad right after finishing my ujoint job.
3. Manifold that coincidentally cracked after ujoint job.
4. Need gear oil in the diff (seals on wheel ends of shafts are leaking)
I have a feeling it's driveline related but I am completely at a loss. Any help or advice would be greatly appreciated. Thanks a lot.

98cherokee531

Check the rubber mount below the transfer case, commonly known issue the rubber breaks down over time and allows the engine and transmission to move when the throttle is applied. The pop you hear is the 4wd linkage moving around in the bushing fixed to the floor of the jeep.

burg3rlicious

So you just think it coincidentally went bad around the same time I did the axle work?

98cherokee531

Not sure but it's easy enough to check and change. Just grab the transfer case and physically wiggle it near the output shaft

burg3rlicious

It has play, but not anything immense necessarily

98cherokee531

Then I'm stumped, nothing else matches up with the description your giving. Nothing I can think of

burg3rlicious

Well I'm not going to rule it out. You're right when you say the signs match up, a new mount is like thirty dollars so I'm going to change it out today and go from there. I'll let you know.

burg3rlicious

I figured it out. I pulled the rear driveshaft and the noise went away. Now I need to figure out whether it's worth rebuilding or not. The shaft is a used front driveshaft that had new u-joints professionally installed maybe 15k ago.

98cherokee531

Kinda weird, does the slip joint in the driveshaft have excessive slop in it? My last cherokee did a similar noise and it was that slip joint moving around because of my front pinion angle being messed up.

burg3rlicious

I didn't take it apart, I dropped it at a local driveshaft shop they're going to give it a once over and let me know. Currently driving on the front shaft....

98cherokee531

Sounds good, let me know the verdict, for now, don't try to race any rice burners in that front wheel drive jeep lol

burg3rlicious

As tempting as it is, I'll try to hold off haha If I get inspired I might just pop the front shaft in back, it's cold today though and I'm lazy