Video of the clunk looking at the forward (diff side) ujoint of the front driveshaft
You can hear the clunk at 18 seconds, and again at 24.
You can hear the clunk at 18 seconds, and again at 24.
Builds 1990 LJ78 in Montana (5 Viewers)
- Thread starter AirheadNut
- Start date
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video of the clunk looking at the rear (tc side) ujoint on the front driveshaft. You can hear the clunk repeatedly after 37 seconds in
- Thread starter
- #323
Is this with the hubs locked or unlocked? Sounds like something is skipping teeth to me, maybe the shift sleeve isn't engaging fully and is skipping under load?
This happens in both 4h and 4l, when the hublocks are engaged.
| TC | hublocks | clunk |
| 4h | locked | yes |
| 4l | locked | yes |
| 2wd | locked | no |
| 4h | unlocked | no |
| 4l | unlocked | no |
| 2wd | unlocked | no |
I've been thinking about the post you made here: seeking vacuum transfer case info - https://forum.ih8mud.com/threads/seeking-vacuum-transfer-case-info.1312666/post-14966752
What happens when the switches on the TC to detect low/neutral go bad?
What happens when the switches on the TC to detect low/neutral go bad?
- Thread starter
- #326
With hubs locked and transfer case in 4WD you'll experience drivetrain binding on hard surfaces like pavement. Can be hard on components, but shouldn't cause immediate damage, especially not when driving straight. Have you been able to confirm the front drive sleeve fully engages?
The switches on the transfer should only be there for the neutral and 4wd indicator lights at this point.
The switches on the transfer should only be there for the neutral and 4wd indicator lights at this point.
I've had a complete front-end rebuild at this point, but I'm not familiar with the front-drive sleeve. Is that the part that engages the TC input shaft to the trans? We did seals and bearings in the TC but not the input-shaft. Is there a way for me to test it without tearing it all apart?
I'll also note that playing around with the shifter from 4h to 4l changes the clunk.. sometimes making it more frequent, other times making it less frequent
oh do you mean the free-wheeling hub in the hublocks?
I tore the hublocks down today just to make sure they weren't over-lubricated, and to see if I could find any evidence of grinding.. they looked good to me. One thing I noticed when I pulled the caps off is that the clutch remained extended and in the locked position even though I had them unlocked before I pulled them off. I know this is a common thing with these aisn's when dudes don't install them correctly, so seems like one of my mechanics maybe didn't get these back on right. But that would have just left them locked all the time. I also went through and tested the vacuum lines with a meter and handpump I finally bought on azn all that looks fine too. I really don't think this is a vacuum related thing. From what John at radcruisers told me, I should be able to place the truck in 4h and disconnect the lines entirely and run it like that (He said it's common for dudes who lose the vsv in the field to suck on the lines to assert the truck from 4h to 2wd and vice-versa.) I tried this and it seemed to work fine. The truck stayed in 4h, and continued to clunk with the lines disconnected from the actuator.
All of the above sounds like a painful process of elimination… sorry for your troubles.
The videos you posted yesterday were not only clunking but something also caused even the camera to jolt. So it isn’t just a noise but it’s actually a problem in the driveline.
Are you completely confident the T/C was properly rebuilt? To me that area just seems like the lowest hanging fruit at the moment. If you were near someone with a spare T/C I would be tempted to pop it on and see whether that eliminates the clunk.
Edit to add - a new T/C is not super expensive out of Japan (definitely not c/w all the other work you’ve had done).
The videos you posted yesterday were not only clunking but something also caused even the camera to jolt. So it isn’t just a noise but it’s actually a problem in the driveline.
Are you completely confident the T/C was properly rebuilt? To me that area just seems like the lowest hanging fruit at the moment. If you were near someone with a spare T/C I would be tempted to pop it on and see whether that eliminates the clunk.
Edit to add - a new T/C is not super expensive out of Japan (definitely not c/w all the other work you’ve had done).
You don't happen to have a supplier contact off the top of your head do ya?
You can definitely feel the clunk in the cab, especially with your hand on the 4h/4l stick
You can definitely feel the clunk in the cab, especially with your hand on the 4h/4l stick
I think I'm gonna throw my phone back underneath it today, placing it near each front wheel, the front diff, and the TC, just to see if I can make the sound louder in the recording somewhere..
Have you tried driving it with the front prop removed?
I have not tried that, but I can give it a shot today and report back
No clunk with the front driveshaft removed. tried in 4h and 4l. No clunk.
- Thread starter
- #337
My guess is that the shift sleeve on the front drive isn't fully engaging, and is therefore skipping teeth when it is put under load. Not sure exactly how to test that without disassembling the transfer case, though.
That's interesting, because the front output shaft is the only part I think they replaced in the TC rebuild other than seals and bearings. They sent me a pic of the output shaft they replaced. Do you know if the sleeve moves to engage with it or vice versa?
Wow, that's crazy. Though, wouldn't they likely have to replace whatever it was interfacing with? Maybe there's your problem...
please god let this be the final problem with this stupid clunk... I went ahead and put in a classifieds want ad for a replacement TC, maybe I can pick one up for not a huge amount and swap them..
