I have a problem - any suggestions

[Andy C]

Buggar - OK last night I was driving home - about a street away from my house I started to notice a knocking sound when I took my foot off the throttle - as soon as I put my foot back on it went away. 30 seconds later BANG and no drive - I moved it from H to HL and could move - slowly still with the knocking sound - luckily I only had to travel half a block where the truck is now languishing in my driveway awaiting mechanical assistance tomorrow.

This came out of the blue - no previous indication - no transmission slippage - no leaking fluids - nothing.

Any suggestions as to what I can tell them that the problem may be would be appreciated - so as not to make me look like a muppet when it comes to mechanics - which I am.

It is a 97 6.5TD with 52000 miles on it.

Thanks guys.

[hmcoleap]

First thought is that you broke something on a halfshaft, CV joint maybe?The banging is probably one end flailing around and hitting things a bit, or just broken parts of the joint grinding together... Could also be a prop shaft u-joint, but that is less likely on an H1.

If you get under the truck, do any of the rubber boots on the halfshafts look like they have a problem? Any goopy piles of grease splattered around?

Where does it sound like it is coming from? i.e. front end, back end, left or right?

Does it sound like metal on metal, any clanging? Or just a dull thumping noise?

Drop me an email if you have more specific questions and are still looking for some input...

-Manny

[NoMoGMPG]

I agree. Halfshaft is the likely source. If after you look at and push/pull on each axleshaft for movement you don't feel anything, I would look at the t/case and driveshafts.

[phazer42]

carrier bearing would be my guess... its the driveshaft bearing on the front driveshaft... probably siezed up and then went kaput...

they can be purchased at a local autoparts store but need to be pressed on and premoved... just ask for one from a similar year / engine Chevy Pick Up.

Scott
'01 HMCO

[hmcoleap]

Heya Scott,

He said there was a bang, and then he couldn't drive anymore... if it was a carrier bearing, I would expect that to generate a lot of noise-- but a seized carrier bearing wouldn't halt his prop shaft to the point that he can't move the vehicle in "H" on the t-case unless he also broke something else, too!

-Manny

Originally Posted by phazer42

carrier bearing would be my guess... its the driveshaft bearing on the front driveshaft... probably siezed up and then went kaput...

they can be purchased at a local autoparts store but need to be pressed on and premoved... just ask for one from a similar year / engine Chevy Pick Up.

Scott
'01 HMCO

[phazer42]

well... when this happened to me in my Humvee it made a ton of racket once I slowed down at constant speed it was fine because the torque was already applied... BUT when I slowed, the driveshaft fell and started to bind up... if when the bearing fails and the bracket was to bend / fail as well it could easily bind up the driveshaft such that the vehicle wouldn't want to move...

its been a while.... whats the outcome of this??

Scott
'01 HMCO

[Andy C]

Sorry - no outcome yet - I was so busy this last week that I just did not get around to taking it in - I have been driving my old CJ7 all week.

Monday I will drag it in and get back to you - thanks to all for all the suggestions at least I will go in sounding as if I know what I am talking about.

[Andy C]

OK I have finally gotten around to looking at the problem myself - Duh - blindingly obvious problem - but one that I have no explanation for.
The right hand side halfshaft has dropped off of the diff plate - I mean the whole thing - all six bolts gone - no signs of shearing - all the holes are still threaded - all I have to do is bolt it back on - I think.

The laft shaft is still in place with no bolts backing out - wait the bolts couldnt back out - the brake caliper would hit them if they tried to come out - even stranger.

Anyway - I will bolt it back on and see what that does.

[Andy C]

OK - bolted back on - working perfectly - weird that all the bolts would back out causing no damage to threads and showing no signs of wear around the plate holes - a mystery to me.

[KenP]

Originally Posted by Andy C

OK - bolted back on - working perfectly - weird that all the bolts would back out causing no damage to threads and showing no signs of wear around the plate holes - a mystery to me.

Leaf-licker with a wrench got you!

[ssgharkness020147]

No Andy thats no mystery. The halfshaft bolts are notorious for backing out. Its a good idea to check them at every oil change if possible. I would advise using red threadlocker on the bolts. You may as well just replace them all along with the nordlock washers. Do yourself a favor and get it all from your local stealership, you want to make sure that the bolts you have in there are the proper grade, as far as the nordlocks go you have to get those at the dealership.

[RonB]

check out these new halfshaft bolt lockers - I haven't tried them but they look interesting.
http://www.h123andmore.com

rb

[tad]

I had that same problem occur while towing our boat out to the Colorado River - all the bolts sheared. What a hassle AND needless to say, it ruined our trip.

[hmcoleap]

The only mystery is how the brake yoke didn't get chewed up when the bolts backed out... typically the heads of the bolts will hit the yoke on the brake caliper and chew it up if they just backed out and fell off.

Originally Posted by ssgharkness020147

No Andy thats no mystery. The halfshaft bolts are notorious for backing out. Its a good idea to check them at every oil change if possible. I would advise using red threadlocker on the bolts. You may as well just replace them all along with the nordlock washers. Do yourself a favor and get it all from your local stealership, you want to make sure that the bolts you have in there are the proper grade, as far as the nordlocks go you have to get those at the dealership.

[hmcoleap]

Now THAT is more typical... once they back out they get sheared off and you have to get the bolts out of the holes on the output flange. PITA!

Red Threadlocker and new lockwashers work. I have had less luck with the nordlocks than with the old fashioned split washers and red loctite, myself.

Originally Posted by tad

I had that same problem occur while towing our boat out to the Colorado River - all the bolts sheared. What a hassle AND needless to say, it ruined our trip.

[DRTYFN]

Originally Posted by hmcoleap

Now THAT is more typical... once they back out they get sheared off and you have to get the bolts out of the holes on the output flange. PITA!

Red Threadlocker and new lockwashers work. I have had less luck with the nordlocks than with the old fashioned split washers and red loctite, myself.

Red Locktite should be enough. If that doesn't work you might consider using a tiny tack weld.