3 speed column shift grinding in 3rd-Help!

[hulleywoodworking]

I rebuilt the 3 speed light duty remote shift transmission for my 51 F1, replacing/installing the following:
NOS Main Drive Gear
NOS Reverse Idler Gear
New Reverse Idler Gear Shaft
NOS Reverse and Low Sliding Gear
NOS Cluster Gear
NOS Cluster Gear Countershaft
New Synchronizer Block Rings
New bearings, spacers, thrust washer, seals, etc.
Clutch, Pressure Plate, and Throwout Bearing rebuilt by Fort Wayne Clutch
Flywheeel turned when engine was rebuilt.
Fresh 80W-90 gear oil, filled to correct level.

So pretty much a new transmission. I assembled it following the Service Manual AND with plenty of research online. The synchronizer block rings were set as per Mac Van Pelts directions, which I found on the web, so I know that the spacing is correct there.

I have the truck up on jack stands as I am still putting it all together. I adjusted the clutch pedal linkage so the arms on the throwout bearing are less than 1/8" away from the 3 pressure plate arms. I adjusted and re-adjusted the remote shift linkage so that it would shift smoothly without the engine running. I started the truck and tried running through the gears. 1st from Neutral fine-1st to 2nd fine-2nd to 3rd a little bit of grinding before it would engage-and any gear to reverse ok if I went through Neutral first. All gears spin the rear tires, and Neutral is just that-neutral.

After screwing around with the adjustments multiple times, I cannot get it to NOT grind going into 3rd. What am I missing?

Is it possible that it grinds because there is no load on the wheels/drivetrain? Or is there a problem here?

Any help would be appreciated.

Thanks,

​​​​​​​John

[alanwoodieman]

syncro ring stuck on the input gear which would make this happen when shifting to third

[hulleywoodworking]

Originally Posted by alanwoodieman

syncro ring stuck on the input gear which would make this happen when shifting to third

So I have to pull the tranny and inspect/fix this?

[alanwoodieman]

you can pull the side cover off without removing the trans--drain the oil-put in neutral, remove shift arms-remove bolts in side cover-remove the cover-get your head up next to it or use a mirror and check the synchro- use a screw driver to pry it off the gear hub, squirt some oil or lube on it and re-install. I was able to do this on a 40 sedan and it had less room than a 1/2 ton pick up. synchro should have some gap between it and the gear so it will work properly if it goes flush with the gear it is worn out or mis-manufatured

[Kurt in NJ]

looks like the only parts not NOS are the syncronizer assy, and the blocker rings

[Mac VP]

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John, I’d recheck the synchro rings you used in your rebuild. I know you purchased some rebuild parts from us a couple years ago. I checked that order from our records and you didn’t purchase any of our rings. We found that quite a few of the other aftermarket rings were incorrectly made. Some sat too far down the cone on the gear. Some had incorrectly machined slots. And some were not true round and would wobble on the tapered cone.

It sounds like the clutch adjustment is not the fault but be sure you’ve checked that as well before you have to tear down the transmission again. A dragging clutch will cause problems with the same symptoms.

I hate it when bad parts make folks have to pull these transmissions back out........

[Flatout]

What gear oil are you using? Some oils specifically state in small print on the back "not for use in synchromesh transmissions"
Use GL-1 in your transmission. NAPA carries it. It's straight 90 wt.
I just drained the GL-5 out of my transmission and refilled it with GL-1. I can notice all ready that the synchros are shifting smoother. .

[alanwoodieman]

MacV, I hate to admit to it but the 40 sedan was mine and as you stated he bought the parts from you some time ago. I built my trans and used just oil to lube the synchro rings and it was some time before I put it in use and I suspect the oil drained off over the year plus it sat, so when I assemble one now I use grease on the rings and have not had any trouble.

[deuce5wndw]

I would take it a drive before taking the trans out! A load on the rear wheels will make a difference.

[hulleywoodworking]

I bought the synchronizer rings as new from 3rd Gen Automotive; he has a good reputation, so they are most likely good, but who knows. I won't know until I open it up.

Thanks everyone. Will drain it, pull the side cover, and see what I've got. Won't be for a few days, so I'll report back what I find.

John

[hulleywoodworking]

PROBLEM SOLVED!!

Thanks to the help I received here!!

I drained the 90 WT fluid and opened up the side. Made sure that the synchronizer block moved freely, which it did. Turns out that I had the shifter linkage hooked up incorrectly; had the rods on wrong. Hooked it up the correct way and adjusted it for smooth shifting without the engine running. As suggested, I filled the gearbox with Sta-Lube GL4 140 WT. Fired it up and ran through the gears multiple times with no problems. No grinding, no hangups, just nice smooth shifts.

Thanks again!!

John