I had this problem ... it was misalignment between my Lakewood scattesrshield and the crank center line. Hopefully, the OPs problem is a simple clutch linkage adjustment for more air gap when the pedal is pressed all the way down. I measured runout when I installed it and it was like 0.016 total (.008 off). I couldn't get the runout below 0.010". It would be 0.008" runout and then I'd tighten the bolts a bit and the runout would grow to 0.014" or more. I'd hit it with a deadblow hammer to try to get it closer but then it would still walk out as I tightened it. I got it as close as I could and welded the dowel alignment bushings onto the scattershield. I thought I could live with it but it dragged and made shifting into first from neutral difficult. I could tell that the cluster was spinning with too much drag when I tried to put it into 1st. It would finally crunch in as I pressed the shifter forward and I'd take off. I finally decided that the 30 yr old bellhousing needed to be retired so I switched to a Quicktime. The pilot bushing was way shot when I took it apart. The Quicktime indicated at 0.002" total runout right out of the box which made me happy. But after just a little bit of driving, the clutch fork pivot bracket folded over and I had to limp home. I think that everyone but me must be running a hydraulic throwout bearing by now but I didn't want to fix what wasn't broken (linkage) and I didn't have another $700 to throw at it. My family is giving me this Sunday off so I hope to bolt it all back together and get it down off the jackstands. Stay tuned ...

I do use the Pennzoil "Synchromesh" NON synthetic gear oil and that has always worked well over the 40+ years that I've been driving a 18 spline 833.

They most assuredly do. What happens when you shift a non-synchro trans from neutral to 1st gear at a stop without waiting for the input shaft to coast to a stop?

Yup just plain 90wt gear oil.

Everytime I see Pennzoil, I make the sign of the cross..

EVERY car ( back in the day) that was using Pennzoil, and was burning oil ( blue smoke), stopped when changed out to Castrol or Kendall, ( the brands I used) after I stopped using Pennzoil...

Many years ago and a different time, but I never use any Pennzoil products...

Does anyone have the product number for the Pennzoil as the pic does not show it.
Thanks

Pennzoil 3501.

Someone asked if it grinds going into gear, I can upshift and down shift no problem, it is only hard to put into 1st if I put into neutral and try to go back into gear,
I have tried the 2nd gear deal before going into 1st and it is hard to go into 2nd as well.

To me it sounds like shifter alignment, shift fork wear (they wear at the ends which pushes the slider assembly at an angle) or something else wrong in the slider assembly itself.

It will go into 3rd and 4th easily from neutral?

based on the responses it might be worth changing the fluid once or twice, twice to flush

keep us posted

I phoned the local Napa and it looks like they have the #3501 so will change it the next chance I get, I will leave the clutch freeplay as is just to see if it is the oil problem.
The shift forks were replaced so they are in good condition, I think I tried the 3 or 4th gear from neutral and almost think there was no difference, there is no grinding once it does go into gear.
What I did notice was that if I went into 1st from neutral it would kind of road block it but if I keep pressure on the shifter it would go into 1st, there is no grinding into 1st or 2nd from neutral, just feels like its blocked but like I said it would go if I keet pressure on the shifter.
When you overanalyze this it does make sense that maybe the oil is too slippery and not stopping the synchros, but when I keep pressure on the shifter it stops the synchros????
Once I change the oil I will keep everyone posted.

I wouldn't over think it....... it's just an oil change.
It will either help or not.

But it may take more than 1 change to flush the slippery stuff out.or some kind of flush, brake clean, acetone ??

Did I miss what happens when going directly into reverse from neutral. If grinding likely a clutch release issue or severe misalignment or tight pilot bearing/bushing drag would be a good guess.

If any clutch drag or pilot bearing drag at all causing main shaft to continue spinning with clutch pedal down, synchronizes will relieve this but with great effort. Going into reverse, of course no synchro help at all.

OH nothing John, just RAM it in, and generate some FLAKES to seat the bearings and parts, Makes for a smoother shifting trans when no teeth are left on the gears.

A warped clutch disc could do exactly what is described. How do you warp a clutch disc?

By letting the back end of the transmission hang down while main shaft is in clutch plate but not yet in pilot bearing is one way. This can warp the disc enough to still have drag even with clutch pedal to the floor.

Question is: Did this all start after overhauled transmission was installed, or was it overhauled because of this problem?

In other words, when did this problem first begin!

Again, what happens when shifting from neutral to reverse? If grinding it is not an oil or synchro problem. It is most like a clutch problem, or remotely a mal-adjusted linkage issue.

Thats true when in neutral and the clutch is out the input shaft is turning as is the countershaft and the syncro's do work when you shift into gear since the gears are turning. Try this and when you push in the clutch and go to put it in first wait about 10 seconds before you try to put it in first after you push the clutch all the way in. By then all the gears should have stopped turning and it should go right in first with no grinding. If it does not and seems no different then when you go into first as soon as you push the clutch in then something is causing the input shaft to still be spinning when the clutch is in. I have seen a pilot bearing that was to tight cause this years ago. If it goes into gear normally then you know the input shaft stopped turning as it should.
Myself I found that if its a clutch adjustment not letting the clutch disengage all the way you will usually also have shifting problems with all gears. I would still make sure the clutch adjustment is right but it does sound like the syncro is not working right. Can the wrong fluid be the cause ?? Myself I have not run into that but from what others have seen the wrong fluid may affect how the syncro's work so it surely wont hurt to change the fluid and try it. Good luck with it , Ron

Pretty sure I remember way back when to use ATF in the 4-trans. I think the one I had used it and it shifted fine. Just a 23 spline, but same principle.

Change the oil and try it, cheap and doesn't take long to do. Probably have to do it twice, but that is what I would do.

I still feel that making sure the air gap is wide enough would be the first step.

If that's found to be sufficient......then change the oil.

Forget the pedal free play dimension and check the air gap at the disc.

Not sure if this was said earlier,if it was sorry.When having trouble shifting into 1st gear,has the op tried shutting the engine off.That would tell you if its a clutch or transmission problem.