Clutch help - opinions and knowledge request

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Jan 4, 2019
Wilmington, North Carolina
Recently picked up this 1965 ‘40. We knew there were clutch issues as there seemed to be what felt like slipping. Had hoped it might be an adjustment issue.
While running it just stopped w a shift to 2nd. No grab at all. Fork moves ok and you can see the clutch disk move away from the flywheel. See video

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Thoughts, recommendations, suggestions?
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Looks like an SBC conversion? Make sure transfer case is not in neutral. They sometimes pop out of gear especially if there’s been a mod to the hi/lo shift mechanism - ‘65 would have that on the dash, is yours there or the floor?
Yes; SBC conversion. Hi/lo shifter is on the dash. What's the best way to check that?
Previous owner reported some odd performance when last shifting from low to high.
Best way for me is to put the rig on stands (or a lift if you have access to one) and with the tranny in gear spin a wheel (front hubs need to be locked) - the other side wheel needs to blocked or held because of limited slip diff. If wheels rotate (and drive shafts) then the TC is in neutral. Try shifting lo/N/hi and see if that locks it up. You can also try this rolling the rig on the ground, shouldn’t roll with tranny in gear and TC in lo or hi, will roll if TC is in N. Mark @65swb45 can probably add more and possible issues with TC shift linkage. GL.
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On stands & in 1st gear, spinning either front or rear wheels and the respective drive shaft rotates.
How to get transfer case out of neutral?

Other question:
Checked the linkage travel when pulling the cable for 4WD high. The linkage travel at what I think is the front drive fork is minimal, a fraction of an inch. Would that be a vacuum issue of some sort?
Could also be slave cylinder adjustment. Sometimes guys try to use a stock Chevy clutch in a Chevota conversion, and the Toyota hydraulics does not have enough travel to fully disengage a Chevy clutch, sooooo they adjust the slave cylinder push rod so that they get full disengagement, BUT then they do not get full/tight engagement, and the clutch slips.
That last video shows virtually no movement so nothings happening there. And that’s the vacuum-driven mechanism that locks the front differential in/out for 4wd, independent of lo or high. The hi/lo shift is mechanical and the lever is on top of the transfer case. You should be able to follow the linkage from the firewall back to the TC. The front drive vacuum diaphragm unit (in your video) gets the vacuum from the intake manifold near the firewall. Check this out - Land Cruiser Vacuum Transfer Shift Assembly, FJ40, FJ45 and FJ55. Tabs at top show different components - lever linkage, vacuum switch and valve, and the diaphragm (that’s what’s in your video).
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And here’s a way to check the vacuum side of things: disconnect the hose attachments to the transfer case (parts 7 in SORs vacuum switch assembly pic linked in previous post), and with engine running (and all safety measures in place - neutral, wheels chocked, p/b set) put your finger on each of the hose ends - parts 7 - and on one you should feel suction. Pull the 4wd lever so the front drive pull switch is activated, and you should feel vacuum on the other hose now and not on the first one. If this isn’t happenening, then there’s an issue in the vacuum switch valve subsystem.

To check the front drive vacuum diaphragm, slide on a 3/8” hose on one of the transfer case nipples and suck - doesn’t take too much - and if nothing happens, put it on the other nipple and try again. If again nothing happens, pull the 4wd level to engage the front drive pull switch, and repeat. If nothing happens - including just a very slight movement in the diaphragm lever - then the diaphragm unit is seized and in need of service (some amount of rebuild). What should happen is the diaphragm lever should move an inch or more in or out depending on which nipple is being sucked. That’s what engages the the front drive shaft. If the rig is on stands you can spin the wheels - hubs engaged - and you’ll see that the front drive shaft engages or disengages.

As far as being in lo or hi or neutral, you need to check that the mechanical linkage to the transfer case is moving as the 4wd lever is moved throughout its range. If it is, then there’s an issue within the transfer case itself needing addressing. If not, then a repair of the linkage is necessary.

And there still may be issues with the clutch as @Downey pointed out. Good luck.
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@Downey thanks for the suggestion. In the video linked in my original post, you can see the clutch move away from flywheel. I've kind of moved on and believe it's not a clutch issue.

@middlecalf thanks for the input and suggestions.
Seems like I might have 2 issues going on here.
1. I can feel the vacuum suction change hoses when front wheel drive knob is pulled out. But still no action on the vacuum diaphragm assembly (is that what it is called)? It starts to move but there is just little travel there. Which leads me to item 2.
2. I'm afraid that the transfer case is shot. Working through all configurations, the only way we get any wheels to turn is when it is in 4 low, and only the rear wheels turn. Could the vacuum shift for front wheel drive be prevented due to damage in the transfer case?
PO indicated he had trouble getting it out of 4WD at some point, and now I'm concerned it was in 4WD on short test drive, on and off trailer, and short around the block drive here.
Maybe I should start a new thread for transfer case issues. And touch base with @65swb45 as you noted earlier.

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