Rear end clunk: give me some peace of mind, please

Diffs, axles, lockers, transmissions, portals, that kind of thing.
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Shovel Bum
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Rear end clunk: give me some peace of mind, please

Post by Shovel Bum »

When shifting, as I let the clutch out and accelerate, I often hear a quick but noticeable CLUNK coming from the rear end. It sounds as though slack is being taken out of the gears or something. I seem to remember this from when I had a Pinz years ago, but that doesn't mean there's not a problem. It hasn't been getting any worse or anything. I've just run out of other things to worry about. Sooooo, is this just a normal Pinz thing, or should I be worried? Please tell me it's normal! Thanks. Will
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4x4Pinz
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Re: Rear end clunk: give me some peace of mind, please

Post by 4x4Pinz »

the oil is the life blood of the pinz. a few minutes after driving the pinz around check the oils and see if there is any discoloring in the oil. By now you should be looking into changing all the fluids to bring it up to current maintenance schedule. The oils will tell you when things are going south. The amount and type of debris on the drain plugs will speak volumes. If all is good then it is possible it is just normal wear and slop. You might also make sure it is not one of the prop shaft ujoints while you are under the truck, don't forget to take along a grease gun for the prop shaft.
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Shovel Bum
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Re: Rear end clunk: give me some peace of mind, please

Post by Shovel Bum »

Right on. Thanks. I'll do that.
Stekay
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Re: Rear end clunk: give me some peace of mind, please

Post by Stekay »

Check the rear transmission mount.
'76 710K
martinlbb
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Re: Rear end clunk: give me some peace of mind, please

Post by martinlbb »

Is-it a 712?

If yes, check intermediate axle between two rear diffs.
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Jimm391730
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Re: Rear end clunk: give me some peace of mind, please

Post by Jimm391730 »

Jack the rear axle off the ground, engage the rear diff lock, leave transmission in gear. Rotate passenger rear wheel back and forth as far as it will go and listen for same sound, look to the exposed U joints for slop or noise at that location, too.
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ExpeditionImports
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Re: Rear end clunk: give me some peace of mind, please

Post by ExpeditionImports »

Would not jump to the differential right off the bat. We are seeing some things come through the shop which are lets say interesting. Suggest you get under the truck and check transmission mounts, engine mounts. Just looking at them might not be enough especially with motor mounts. The weight of the motor can hide a cracked/separated rubber in the motor mounts.

Those transmission mounts do wear. We have seen some interesting "fixes". Should not look like this one.

Cheers,

Scott
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712M 1648 Transmission Mount.JPG
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Last edited by ExpeditionImports on Tue May 05, 2015 8:54 am, edited 1 time in total.
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ExpeditionImports
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Re: Rear end clunk: give me some peace of mind, please

Post by ExpeditionImports »

This one was not much better.

Cheers,
Scott
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Expedition Imports Corporation
Vallejo, California
www.expedition-imports.com
"You didn't buy a Chevy..." "Hows that Amazon tech support working out...."
ExpeditionImports
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Re: Rear end clunk: give me some peace of mind, please

Post by ExpeditionImports »

Here is what the mount looked like when all the bolts and "fixes" were removed.

Cheers,

Scott
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Expedition Imports Corporation
Vallejo, California
www.expedition-imports.com
"You didn't buy a Chevy..." "Hows that Amazon tech support working out...."
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