1984 K10 longbed, auto tranny, auto locking hubs, stock tires, 75,000 original miles, daily driver...
Truck had been running fine up until yesterday. Backed out of a parking spot with a tight turn, put it in drive and about 10ft later noticed a binding and knocking sound coming from the drivers side front tire area. Backed the truck up a bit, and moved forward again with no further issues. Truck had been in 2wd the entire time and hadn't been placed into 4wd for well over a month.
Worked a night shift last night, went to leave this morning, backed the truck up out of a parking spot and noticed the slight clunking/knocking sound again in reverse, and it became extremely noticeable when I started to drive forward. Backed up again and went forward without issue, and then the clunking/knocking started again about 20yds later.
After trying a few different things, between shifting into and out of 4wd high, 4wd low, nuetral, and 2wd, backing up, moving forward, extreme turns to both sides in both forward and reverse. Here's the jist of it...
Truck runs completely fine in 4wd, anytime the problem presents itself, shifting into 4wd makes it go away. It appears that the front hubs do sometimes not disengage when shifting out of 4wd unless traveling around 15-20mph or so when shifting into 2wd. Anytime the front hubs seem to be engaged, the problem is not present, only appears when the front hubs are obviously no longer engaged. The issue is not constant and was never even present until yesterday. It only appears to be happening in 2wd and is irrelevant of direction of travel, straight or turning in either direction. At a higher rate of speed, approx 20mph or more, when the problem presents itself, it sounds like a clicking and rattling sound as if there were gravel or something in the hub, until speed is reduced and the loud knocking/cluncking starts around 5mph or less. It appears there is more than one knock/clunck per wheel revolution and seems to be isolated to the drivers side front hub area. There is no noticeable effect on the steering wheel.
My thought is that the auto hub is not fully disengaging and is hung up somewhere between engaged and disengaged. Either a bad hub or some problem with however the hub disengages. At higher speeds it rattles around until the rotation slows enough where it attempts to engage and results in the knocking/clunking/binding. It's almost as if something is hanging up and then lets loose...hanging up, letting loose, etc..
Would replacing the auto hubs with a set of Warn manuals fix the problem?
Is there anything else that I should be looking at?
Will this cause any damage to anything other than the hub?
What restrictions should I be following in regards to driving in 4wd on dry pavement until I can get this fixed? max speed, etc...
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