Clunk identification

[rbagley]

https://youtube.com/shorts/xHeu2jGT9m0?

Does this clunk have an obvious cause to anyone? it usually clunks as I engage or disengage the clutch, but sometimes in 2nd gear it will do it a couple seconds after letting off the clutch and accelerating.
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[kwmech]

Linky no worky

[Getter-Done]

Have you checked the bushings on the cross tube from the frame to the bellhousing?
Does the spring have return spring have good tension on it?
Does the throw out bearing fork have excessive wear?

Here is a direct link to your video.
http://www.youtube.com/shorts/xHeu2jGT9m0

[kwmech]

Truck in neutral, block of wood front and rear of the tires. Check the rear drive line paying attention to the back of the t-case. Wiggle it around. There should only be a little movement while turning the shaft. Sounds like excessive gear play

[Palf70Step]

My thoughts were the carrier bearing.

Fixed your link

[Ironangel]

Originally Posted by kwmech

Truck in neutral, block of wood front and rear of the tires. Check the rear drive line paying attention to the back of the t-case. Wiggle it around. There should only be a little movement while turning the shaft. Sounds like excessive gear play

This as well as the backlash in the pinion at the rear axle. Shouldn't have but a couple of degrees of slop either way when you turn the rear drive shaft by hand.

[CUSTOM/10]

Possibly the transmission output shaft spline & coupling splines worn, common on the manual transmissions.

[Grumpy old man]

I think you all are digging too deep . I'm thinking it's the drivers side motor mount , On a car of the same age the shifter would be torqueing over to the right but with these old trucks and having a bell housing Mounts the shifter wont torque so much that the shifter will move to the right . I'd start looking there before digging further .

[mongo4298]

I agree it could be the coupling between the transfer case and tranny. Pretty much normal gear slop with a limited slip also. Noise would be more noticeable with the tranny cover exposed? mongo4298 See attachment

[rbagley]

Thanks for the ideas. It will be a couple days before I can get back under it, but I’ll post my results once I do.

[Ironangel]

Originally Posted by Grumpy old man

I think you all are digging too deep . I'm thinking it's the drivers side motor mount , On a car of the same age the shifter would be torqueing over to the right but with these old trucks and having a bell housing Mounts the shifter wont torque so much that the shifter will move to the right . I'd start looking there before digging further .

A very real possibility. The sound seemed to be close by in the video.

['68OrangeSunshine]

My funny noise turned out to be the forward prop shaft disintegrating.

Thought it was out-of-balance new tires on 1.25'' wheel spacers. Changed back to old 15'' rims and 33x12.50x15 knobby tires. Wasn't it.

Checked differential with rear end lifted. Front shaft rotated, too.
OK, so the Transfer case had got shifted to 4-Hi and I ran it on the freewy unawares. Back to 2-Hi. Sounded better.
But still a nagging tink-tink in the front.

A closer look showed a lost retaining clip on the 2nd U-joint on the front shaft was working the bearing cap loose.
I got a fresh U-joint to replace it. When I got the bad U-joint off, I saw some little bearing cup inside the double-cardan had disintegrated over a period of years.
So I had to pull the front prop shaft.

Noise is gone on my now-2WD K/1500 Jimmy.

A new one will run $650 from Jegs.
The front shaft on my '67 K/10 Sub appears to be identical. When I get time off, I can cannibalize that.

[rbagley]

Here’s a little update on my situation. The engine side Z bar pivot ball snapped off flush with the block yesterday, so I had all kinds of opportunities to climb underneath it. Here’s a video of the driveshaft play. Is this a normal amount? This sound seems the same as what I hear as I engage and disengage the clutch. I took a peek at the drivers side motor mount as well and it looks like it’s fought the good fight. Maybe related to the clutch pivot breaking?

https://youtube.com/shorts/GX1Va1N5lOY?feature=share

[kwmech]

The second video driveshaft play is (in my opinion) a little excessive. Unbolt the shaft and check both the pinion and the rear output of the t-case.

['68OrangeSunshine]

The Clutch Return Spring on my '71 Jimmy broke when coming home on a Friday, week before last.
Coincidently it was Cinco de Mayo, [Mexican Independence Day] and I was in South Tucson -- the heavily Hispanic district. I might have mickey-moused a temporary fix with baling wire, but I called in a tow truck instead.
I had a four hour wait due to the holiday.
The next day, I bought the biggest screendoor spring I could find at Ace Hardware.
It was too short. Then I tried an S hook, I was saving for a dutch oven.
Did the trick.
Works great.

[Ironangel]

That's to much backlash, move the ring gear closer to the pinion. The transfer case is probably due for a rebuild as well. Backlash should be in the .006" -.012" range. If that pinion moves for and aft at all, it's due for a rebuild. All that free play beats everything from the differential to the flywheel to death. I'd start with the rear axle, new axle bearings and seals, if the pinion has any end play, sometimes tightening the pinion nut a bit will eliminate the free play. Move the carrier toward the pinion by removing shims from the right side carrier bearing shim pack and placing them in the left side shim pack. I'd start with .020" and check the backlash. Factory 12's (some) had one piece cast iron shims that were ground to fit, they were right at .250" thick and work great if you can keep from breaking them. The "Super Shims" from Randy's Ring & Pinion are the bees knees as they wont damage removing and installing them. Good luck!

[special-K]

We may be looking at a couple of things here. Only one thing making the clank. I'd say the engine rocking from the played out motor mount is why the pivot ball stud snapped. That could have been the sound you were hearing. I'm assuming truck is down for pivot ball and haven't driven to hear the sound yet

[rbagley]

Originally Posted by special-K

We may be looking at a couple of things here. Only one thing making the clank. I'd say the engine rocking from the played out motor mount is why the pivot ball stud snapped. That could have been the sound you were hearing. I'm assuming truck is down for pivot ball and haven't driven to hear the sound yet

You are correct that the truck is down while I wait for the new pivot ball to show up. I'm not sure if it's relevant or not, but the noise has been the same for the year or so that I've owned it.

Any tips on getting the rest of the pivot ball bolt out of the block?

[Sheepdip]

Originally Posted by rbagley

You are correct that the truck is down while I wait for the new pivot ball to show up. I'm not sure if it's relevant or not, but the noise has been the same for the year or so that I've owned it.

Any tips on getting the rest of the pivot ball bolt out of the block?

Right angle drill with a left hand twist drill bit should take it out. If not EZ out will do it.