83 K5 Strange Noise...

[476k5]

Hey guys looking for some guidance on this one. Back story that I think may be relevant, last year was testing my 4x4. Forgot to unlock the hubs and drove home on the highway. Max speed was about 70mph. When I got home I found the transfer case had spit some fluid out of the breather. I smacked my self for the stupidity, unlocked the hubs and forgot about it. Drove fine all last year and up and till now. Current issue, we have had nasty snowy weather in my area so I lock the hubs and had been using 4x4 as needed on my commute. Again everything was fine. Once it started clearing up outside and I saw that there was some dry pavement I unlocked the hubs. Touch a drive out in the country and needed to shift into 4x4 and found it was a little difficult to move the shift lever into 4hi. Moved the truck back and forth a bit and got it in. After use I put it in 2hi and unlocked the hubs. Now I am hearing a strange humm from I think the front end. I seems to only be effected by speed and is most noticeable at 35 to 40mph. Can anyone shed light on this noise for me? I am thinking about swapping the diff fluid and transfer case fluid.. the transfer case ( recently re-built ) and front end are stock.

Thank you for the help!

 

[paratrooper307]

Hum may be bearing or gear noise. A fluid change is a good place to start. Are you saying the hum happens in 2Hi? If so, that would seem to rule out a transfer case/hub issue. Sometimes, if there is a load on the drivetrain, you might have to do what you did to release tension to shift the case.

Even though you're not supposed to drive at highway speeds in 4 Hi, I've done it before with no problem, the main issue is doing anything that would result in differential speeds, like turning, since that will scrub the tires and cause driveline stress.

 

[diesel4me]

Front shaft u-joints can wear rapidly at highway speeds,so can the axle shaft u-joints..all it takes is one to develop a scollaped wear pattern on the journals from the needle bearings and they start humming--and fail,eventually..but in 2wd,after a few miles,the front shaft and axles shouldn't be spinning,so that would tend to rule out the front end as the noisemaker...however, rear u-joints can do the same thing..

Wont hurt to check all the u-joints and maybe the front wheel bearings for any excess play too...