We got the trans out and inspected the parts. There is about 50k miles on these clutch components. The flywheel and the flywheel side of the clutch disc look perfect other than normal wear but its perfectly uniform. The pressure plate side of the clutch disc has uneven wear, three of the inertia springs are marred and very loose and there is some strange spotting on the pressure plate surface. The throwout bearing looked normal and there was normal wear on the pressure plate finger tips where the throwout bearing rides. The pilot bearing and input shaft snout appear normal and the bearing moves freely without binding. I measures the thickness of the clutch disc in numerous places around its perimeter and the measurements are not uniform. They fluctuate .3mm for one area to another. So maybe there is warpage.

We looked through the inspection port before removing the transmission and the throwout bearing was pushing the pressure plate fingers in more than enough so hydraulics were further ruled out.

Here are a few pictures.

 

Anything other than "normal wear" would be suspect, and what I see is not normal wear. The springs on the clutch disc - worn on the side - are definitely indicative of something that was wrong in there. Make SURE upon reassembly that the clutch disc faces the correct way.

So good that you got in there and are replacing that stuff.

 

The clutch disc assembly is multiple pieces obviously. Friction discs sandwiching thinner independent steel rings. I think the inner steel rings are deformed and spreading the friction discs apart. This may be caused just enough drag to make gear engagement difficult. It will be interesting to compare the new disc visually when it comes in. The deformed inner steel discs may be related to the marred inertia springs.

 

Here's a brand new and my used clutch discs from my 1970 VW. Note that the springs on the used one do not have wear like your springs do.


The side facing "up" goes toward the pressure plate, the "down" side goes against the flywheel.

 

Update: We're back in business with the new clutch installed. Incidentally we had a spare used transmission on hand that I had pulled out of a junkyard a couple years ago or so. The trans that came in the truck was always a little wonky. It's problem all along was difficulty downshifting into 2nd. It would grind and crunch and sometimes you would need to almost come to a stop. We think the synchronizers are worn Anyway, since we had it out we threw caution to the wind and put the other one in. To our delight it works perfect with no troubles downshifting in any gear.

Subsequently, we discovered the main problem with failure to disengage making it impossible to put it in gear from a stop with the engine running was bent components in the clutch pedal mechanism. If you remember I told you my son said the pedal at one point suddenly became jammed and wouldn't go down. Well, he pushed way too hard on it and it bent the through bolt that the pedal hangs from and pivots on. He bent it enough that it prevented full depression of the master cylinder piston. I still don't know for sure what made it jam up. Anyway, I studied the bent through bolt and decided that even if I were to disassemble the assembly so I could straighten the bolt, it was bent enough that it may not even pull out of the steel tube that it goes through. I thought, maybe if I remove the nut and pedal I could get up in there with a leverage tool of some kind and bend it back. Well, even though I may still try that in the future, I opted for a slight modification to remedy the problem for now. I cut a 1/4" long piece of grade 8 bolt the same diameter of the pushrod and set it down into the master piston hole where the pushrod goes. This trick restored the lost travel and now its working fine.

In hindsight, had we caught this bent through bolt sooner I'm pretty sure we could have been back in business without pulling the trans. But we're not upset about the cost of a new clutch kit because the other one had 50k miles on it, the pilot bearing although not seized was dry in spinning and the throwout bearing was a little loose too. But the big winner was the spare transmission works fantastic compared to the other one. Those few hours I spent pulling it in the junkyard and the $165 they charged me were well worth it.

Thanks again to everyone for your help, we really appreciate it!

 

I think you are better off now, with a new clutch kit and a different trans......if you haven't done so already, change the old gear oil in the new trans......it will work even better!

 

We actually did drain the old gear oil and filled it back up with Valvoline full synthetic 75w-90. It took about 2 1/4 qts.

 

Great job. And you learned a lot, and so did folks here !!!

I sure didn't like the weird wear on the clutch disc springs.