I have a 1998 Jeep Cherokee 4.0L

I have a Dana 30 Front and Ford 8.8 Rear

I bought Yukon 4.56 ring and pinion sets and master install kits for both diffs and had a shop install them. While they were installing them I had them do an alignment too.

Now, between 30-45mph and around 65mph I have some bad vibrations in 2wd and in 4wd hi the vibrations are even worse at those speeds, they get worse while decreasing speed as well.

I'm going back to the shop tomorrow and asking them wtf they did to my baby. But for now do you guys have any idea where they went wrong so I can maybe ask the right questions?


Thanks in advance.

 

Not to come off like a (fill in explicative here) but why would you drive 30-45 mph in 4 high? (and I certainly hope not 60+!). Now that I have gotten that off my chest I would definitely go back up there and have them check over everything. My guess would be that some part(s) are warn out,and have been for some time; So putting it back into proper alignment caused a vibration. Also, I'm not sure about your lift specs but considering you have an 8.8 swap also I'm sure your far from stock. With that being said, many shops aren't very good with aligning lifted/modified vehicles and you may have to find another shop to get you back to where you should be,ride quality wise. Good luck!

 

Why shouldn't he drive it at 30-45mph in 4 high? It will casue no problems or hurt anything.

 

Yeah, driving in 4 hi is fine. Shouldn't drive like that all the time but it's got nothing to do with speed and everything to do with driving in 4 and turning on dry pavement.

Sounds to me like they may have set the front pinion angle wrong. Can you take a picture of the front axle/pinion? Maybe grab pics of other relevant things while there

 

Yeah, I'm pretty sure Hi 4 is to increase traction on slippery roads. I just wanted to test out the new gears to make sure everything was good, which I don't believe it is.

My Cherokee isn't anything extreme passed stock. I have an 8.8 rear and an 8" lift but I've still got short arms and a Dana 30 front

And I can snap a picture in the morning definitely!

 

you did not have this problem b4 they adjusted it correct no bad tire wear or wobble issue

 

I'm pretty sure a lot of people would consider 8" lift pretty extreme, and bet it rides nice on the road with short arms...

Ask the shop how far the Jeep was out of alignment (assuming you didn't get any papers with it). If it was far then my guess would be worn parts due to being out of alignment for a long time that only showed themselves when the alignment was correct. The other thing to check is your u-joints, the caps could have gotten screwed up when they were put back in.

 

im sitting on 10.5 inchs with short arms ride good its all in how you assemble your lift

 

could your driveline angles be out?? ive heard that gears can exaggerate driveline vibes if it isn't sitting correctly!

^^^ holy mother of god, 8" on shorts!?!

 

Front Diff


Rear Diff


Before Alignment


After Alignment




I can take anymore pics or answer any other questions you guys need.

 

How about a head on shot of the front end. Is your trackbar and draglink parallel?

 

Hows that look?

 

What size tire is on it and what gear did you have before? The driveshafts are going to be turning much faster now at the same road speed, maybe you justnever noticed because it came in at a much higher speed.
Grab your driveshafts and make sure the u-joints feel tight also.

 

I have 33x12.5 tires on it and 3.73 in the rear from the previous owner and I never had it in 4wd cuz the front till had the stock 3.55. I'm not very experienced with this stuff, like grab the drive shaft and move it front to back to see if its tight or turn it?

 

Oh, and I have matching 4.56 in now.