Grinding

Gufshoz

Gufshoz

Member
I just finished changing all of the fluids after a 2000 mile trip in my A. No issues during the trip, but now I can't shift into 2nd and 3rd without severe grinding. I can get into all gears from a stop. My brother, who has a lot of mechanical experience, suggested that my new gear lube is too thick to allow the gears to slide on the sector shaft. The new gear lube is GL 1500, from a Model A supplier. I don't know what the previous lube was in the transmission as it was put in by an engine rebuilder. I'm in the process of contacting him.
Thoughts?
 
600w is what is called for and that's all I've ever used. I couldn't find any info on that GL1500 stuff. But if this just started after you put that stuff in, I'd say its probably what's causing it
 
Simple stupid is were to start. Change your transmission again. Get another bottle from a different supplier. I have been using half 600w and half STP. Has worked well for many years.
 
Mitchell, who make the synchronized Model A transmission, recommend 85W-140 G5 gear oil in their transmission and overdrive. This oil has an additive that protects the metal parts from wear. It is multiple viscosity so that in the cold winter it acts like SAE 85 and in the summer SAE 140. The cold weather is not helping your gear shifting.

The 600W that you get from various sources does not have any specification that controls it. The 600W that was available in 1930 was the best then, but it is 90 years later and oil has improved. Aside from a Honda motorcycle,I don't know what GL 1500 is but probably it is part of your problem.
 
While waiting to reach the previous rebuilder, double check the pedal clearance AND the clutch shaft arm pinned to the shaft. After 90 years this pinned area can crack, split causing shifting problems. Not uncommon.
 
I had the same symptoms you have. In preparing for a cross country I too changed all the fluids and then the transmission would grind. After talking with everyone I knew I called MODEL A MEDIC 316-619-1821. He works on cars and sells parts. He said every parts supplier has their own formula for 600 wt. Mine was to thin allowing the gears to spin and not mesh. He sold me 600 wt. from VINTIQUE knowing exactly what my problem was and said I could add some STP also. I guarantee this is your problem! Very nice guy to work with. He saved my butt!
 
The SAE gear oil viscosity grading came out before Ford finally changed away from 600W Steam Cylinder Oil. Henry worked in Locomotive shops in his early days and change wan't something that came easy to him.

The 1500 mentioned appears to be the later ISO international standard. ISO-1500 is at the top of the list when compared to SAE which puts it at the top of the SAE-250 gear oil viscosity range. 600W was not quite that thickness of viscosity, It compared more to the SAE-140 to SAE-190 range so it's not quite as thick as the ISO-1500.

When Ford went to the synchronized transmission in 1932, they changed to SAE-80 winter and SAE-90 summer but it is a synchro type unit. The spur and dog unit of the model A can use a more viscous lubricant but a lot has to do with how well a person can match rpms during a shift up and especially during a down shift attempt. The engine rpm versus main shaft rpm have to be pretty close to get the gears to slide in like they should.
 
So this morning I put Castrol; Axel; GL-5; SAE 85W-140 into my transmission. After driving for a few miles and shifting quite a bit...the problem is solved. I went with nkaminar's suggestion for Mitchel transmissions and overdrives. I was a little concerned about their products being syncronized, but that wasn't an issue. It took a few shifts for the new lube to displace what was left of the old stuff, then it was back to normal.
I want to thank everyone for their input and suggestions
Terry


PS: I just heard from my engine rebuilder and he had put in 600W (part #M-533 from Snyders). I can't tell the difference from the 85W-140 that I used.
 
Last edited:
Gufshoz, Thanks for letting everybody know the outcome. IMO, everybody should do that. When ever somebody posts asking a question, there are always many and varied responses. It's good to learn which was "on the money".
 
You must log in or register to reply here.
Back
Top