Front end clunk or bang

[KPSquared]

Tonight was the first time out after the rebuild.

New lift (superlift 5.5") new pivot bushings, new RA bushings, new ball joints, new pads and rotors, new Warn Jeep hubs and fresh installed 4.88 gears.

When I switch from forward to reverse in 4x4 it clunks or almost like a bang once I hit the gas a little. Can feel it through the floor board. NOt sure where to start. Just had the drive shaft out today and all the joints feel good. Can something bind in a brand new manual hub and cause the clunk?


I posted this in the stock first gen forum, but it should have gone here, so feel free to delete the other post mods...

 

[lifted93xplorer]

If the clunk was not there before the lift you should crawl under it and check every bolt. Been there before, you think your friend got it and he thinks you got it. If you feel it in the floor and only in 4x4 start from the t-case and move forward, or block the tires and have a reliable friend (not the guy who forgot to tighten the bolts..:smoke:..) shift back and forth until you see something moving or at least find the source of the clunk. Could be the trans mount shot. I hope it isn't the front diff having too much backlash but it doesn't sound like that. I have had the same noise as explained, from bolts coming loose on the transmission cross member, that as it's shifted from drive to reverse or vice versa will clunk then with a little gas will bang loudly and be felt in the floor. This will happen whether in 2wd or 4wd but it's more pronounced in 4-low obviously. On the plus side I highly doubt it's a hub. I hope it's just something loose and not anything major.

 

[KPSquared]

Ya, if I ease into it, there's no bang. It's like something loads up then shifts. It does it in 4 hi and lo.

I was out in the snow and if I just rolled ahead after being in reverse, it wouldn't do it, but it I tapped the throttle, it made the bang.

The hubs are fine, checked the wheel bearings...

How tight should the radius arm nuts be? Is there a torque value? If they were to tight maybe?

Also, the spring retaining stuff at the bottom of the coil doesn't actually squeeze the coil, with the nut right tight, I can still spin the coil if it's not seated in the upper bucket. Could that being loose cause a bang?

It's really weird. None of this happened before the lift and other stuff. The tranny and t-case were find pre-lift...no noises.

 

[lifted93xplorer]

lower radius arm bolt:330 ft. lbs./upper bolt:250 ft. lbs./ rear nut:120 ft. lbs. lower spring retainer nut:100 ft. lbs.

 

[lifted93xplorer]

the lower spring retainer is more to hold the spring in place while the suspension is hanging just as the top is intended and no I don't think that's your noise. Also if the bushings are too tight they will just wear out prematurly. How about the RA drop brackets, they tight? same goes for the axle drop brackets. I would check the torque on the radius arm to axle bolts also, they need to be damn tight

 

[KPSquared]

I'll go over everything tonight. I am thinking I didn't get the radius arm bolts tight enough. It's more of a bang/ping than a clunk. Like something loads up then releases. It almost resonates like with a ring. Bong..

If the RA bolts were not tight enough, I could see it loading up then slipping 'cause the holes are slightly bigger than the bolts.

Nice thing is, I've had this thing apart so many times I can have the axle on the ground in about 10 min...

 

[lifted93xplorer]

Good deal, just remember if you can't find the clunk have someone shift it back and forth while your under it and you'll find it for sure.

 

[KPSquared]

Lying underneath may not be a good idea...you really gotta stab the throttl to get it to go...
We'll see what happens. Should know tomorrow. Thanks for the help!

 

[lifted93xplorer]

Yeah, if you have to stab the throttle I'd be careful. Don't it still make a clunk just shifting it in 4-low?

 

[KPSquared]

Ya, it clunks going into 4 low, but those are normal noises... this is a totally different animal. Like, smack a coil spring with a hammer but sharper and harder sound... like and bang with a resounding bong... Anyway, gonna tighten stuff up and see what happens...

 

[4x4junkie]

I'd suspect the radius arm/axle bolts also. With bigger tires they need to be @#%$! tight! 250ft-lbs at minimum, 300 is better.