Vibes ONLY in 4WD after ECGS install

Installed ECGS bushing to get rid of 2wd vibes around 40 mph. After install, I took the truck up to 60 in 2wd and all was good. Found a straight road and put it in 4wd and brought it up to about 45 mph. Every time I'm off the gas at any speed, there's a new vibration and grinding sound from the front end. It's pretty loud and I can feel it in the pedals slightly. Again, this is ONLY in 4wd.

Anyone had this issue? Is it possible that this is caused from improper ECGS bushing installation? I set the bushing flush with the carrier as per ECGS install instructions. Maybe I marred the bushing and didn't notice? Or somehow damaged the CV when removing it?

Everything seemed to go smoothly and I didn't notice anything out of the ordinary during the teardown and install. Any ideas would be most welcome before I buy another and tear into it again..

A couple more notes:

• I did refill diff fluid after the job
• I did remove the rag that was shoved into the diff to keep the tool from falling in
• I replaced the diff seal while doing the job
• Nothing is leaking
• Every bolt removed was re-torqued to factory spec

 

Did it do it before the ecgs bushing?.. I’m sure it “hummed “ from the needle bearing but did it vibrate?

 

I couldn't feel it in the pedals before doing the ecgs bushing

 

I just reread your post, grinding sound… can you Jack up the truck and doin it over by hand and hear it.. I know you said you double checking everything.. but something gave upon disassembly/reassembly ..as far as the east coast installation done wrong, I highly doubt it.. I’ve done three, and never had a problem..kinda sounds like a wheel bearing

 

Under 45 are you good? Do you drive in 4wd at or over 45 often? If not — maybe nothing to worry about.

 

The CV axles ALWAYS move, Even in 2WD.
The front driveshaft, the ring and pinion do not turn in 2WD.
A noise under deceleration is usually a sign of a bad pinion bearing or bearing preload.

However, your noise started after the install .Maybe it was a coincidence?
At the least, crawl under the truck an give the front driveshaft a look. check the u-joints and the "play" at the pinion.

 

Did you lube up the inside of the bushing before you popped the axle back in?
Is the axle seated sufficiently?
Yes, crawl back under it and have a look around.

 

Thanks for all the replies, here's a quick update:
I took everyone's advice and checked around under the truck. The front DS u-joints seem fine and I lubed them up. I can't hear the noise when spinning the tire by hand. The axle is well seated and has much less play than before the ECGS bushing upgrade.

For peace of mind, I ended up buying another ECGS bushing. I did marr the old bushing because I didn't use the proper tools for it, so this time I used the ECGS install tool and it went in smoothly. Turns out, the noise is still there after installing a new bushing properly. I don't have any need to go 45+ MPH in 4WD often so I'm just gonna.. forget about it for now. Might take a closer look at the front DS at some point in the future though.

The only thing I'm confused about is that I could go these speeds in 4WD before I did the ECGS bushing and I never noticed any noise like this. Oh well, maybe I'm just being paranoid

 

Maybe rotate the tires and see if anything changes?

 

Maybe that hum from the bad needle bearing covered up the nee to you noise.. possibly a weight fell off causing the front driveshaft to be outa balance‍♂️

 

I mean
You can make sure you installed it all properly. Bit of a pain to do.

and if fine, look elsewhere. Other things can cause this.

had a vibe in 4x. Marked and rotated my front DS at the front flange the other way based on the pattern imprint and it went away. So I guess 180deg.

thought about taking it off to drop off at a shop for service and balance. Replace u joints. But being a front part time use shaft I doubt it’s worn like a rear main propshaft.