H3T Front Differential noises

[pepino1256]

Been having some vibration/grinding noises under medium to heavy acceleration. Mostly happens when going from first to second. I had a tiny amount of play in the U Joint so I replaced that. It seemed a little better but it is still there under anything but light acceleration. I did pull the front driveshaft, lock it in four high and the noise is gone, therefore i'm fairly certain it isn't the transmission.

I'm thinking either differential bushing/mount or its time for a differential bearing replacement.

Your thoughts?

 

[SlcHummer]

I had a cheap cardone cv axle installed which caused a minor grinding which was really only noticeable around 5-20mph. I had several friends drive my rig to see if I was crazy and most did not notice the grinding but were also unfamiliar with my rig or H3's. I ended up having a new boot put on the OEM cv axle and swapped it back in which solved my grinding issue.

 

[pepino1256]

PROBLEM SOLVED!

Definitely wasn't the cv axel. Pulled everything apart and found that my differential bracket on the passenger side was super bad. I could wiggle it back and forth with my fingers. I changed both side but haven't made my way to the rear bushing yet. Also measured the front ride height and the truck was sitting at 24.5 inches from the fender lip to the center of the hub. From my research on this website I've seen that anything over 23.5 and you asking for your parts to wear out faster. I figured it was the ride height because when I loaded my dirt bike on the hitch carrier it exacerbated the issue 100x more. The truck was barely drivable!

Anyway, after replacing those right and left bushing/brackets it helped the grinding/vibration under acceleration but didn't cure it. I backed off the T-bars 4 revolutions and the noise has disappeared. Right now I'm sitting at 23.25". I really liked how it looked leveled out and I am stl planning on replacing the rear diff bushing but it was good to finally figure out what was going on.

 

[Jeepwalker]

Did you tripple-check the splines and yoke on your driveshaft? Is there a constant velocity joint on the driveshaft (honestly I haven't looked at mine)? Grab the driveshaft (as installed) and violently wiggle it up and down with all your strength. There should be virtually no play. If it has a CV, the ball on driveshaft CV's (in general) don't usually get lubed enough and can wear out and cause vibration as you are describing. It's not the ball that wears out, it's the cage bearing the ball fits over. That pertains to Jeeps and a lot of GMs that have front driveshafts with a CV joint.

You're right about ride height. People tend to want to 'look cool' but raising the front end you're changing the parallelism of the front axle shafts and can lead to premature worn parts. But that usually takes a long time, maybe years. Grab and wiggle the axle shafts where they come out of the diff. See if you detect 'play'.

 

[SlcHummer]

What kind of cv axles do you have installed? Could it be possible you had to reduce your t-bar crank because of the branc of your cv axles? For example, in my case I swapped an after market cv axles for oem, leaving my t-bars cranked, and grinding/vibration issues were resolved. Where-as you reduced your t-bar crank to resolve your issues, maybe allowing an aftermarket cv axle to work just fine at reduced angles? Just a thought.

 

[4speedfunk]

The harsh ride was caused by the shocks being “topped out”. At 24” of height, the shock shafts are fully extended, and they are essentially a solid bar connecting the lower A-arm to the frame. The stock shocks have a very limited range and many H3 guys run longer shocks for this reason.