The Stovebolt Site Forums The Shop Area Driveline 1953 3100 3rd Gear Grind

When I first got the '53 a few months ago, the only gear it would shift smoothly into was 3rd. I was having trouble with it getting stuck in between the other gears (shifter jamming). After lots of reading, studying the linkage system (column shift) and experimenting, I learned how to set up everything properly according to the shop manual. I really feel at this point that I have the shifter and shift linkage setup right with no unnecessary play in the shift system. I can shift into all gears perfectly when the truck isn't moving, but when I'm driving and going from 2nd to 3rd, it wants to grind and I can get it in 3rd with minimal or almost no grind at all if I slowly drop it into 3rd and easily work it into gear. So I'm confused. Downshifting is not a problem at all and I'm going to change the transmission oil next to see if that helps. Any thoughts? Could it be the syncro ring or shifter fork if it was shifting into 3rd easily before I calibrated the shift system? I don't see how that would be possible.

I would think that you have problems with the 3rd gear synchro operation. I have no idea what changed. Most of us start double clutching when these problems start to appear. If you shift really early and it works, I would say it is a synchro problem. You could also bring the idle up some with the cable control and see if that affects it. Some folks find that a heavier transmission oil helps the synchros work better.

Thanks for your input truckernix. I actually have been double clutching. I always drive it that way, which makes me more confused. The issue happens whether I double clutch or not.

Yes, I have just gone through this with my 38 Master. I finally have a transmission that works correctly. When the transmission is operating correctly, there is no need to double clutch. Of course, first gear is not synchronized.

Well, I've made a little progress with the oil change. When i drained it, only a little bit of very black oil drained out and I filled it with 90W mineral oil as called out in the shop manual. The first time around the block, it shifted without grinding, second time around I thought I felt it a little but couldn't tell for sure. As the engine heated up from driving around more, it was grinding some, but nowhere near as bad as before the oil change. My question now is, should I add some Lucas oil additive to help as the oil heats up? Does anyone think that may help or do you have any ideas why it grinds a little as the engine/transmission heat up?

There may be a thicker oil that you can use. There is a Lucas product that is very thick but you don't want to sacrifice the bearings. There is also a Lucas additive for limited slip differentials and also automatic transmissions. It is supposed to help with friction on the clutches.

Thanks, I've got some of the Lucas additive and I'm going to try it this weekend. Fingers crossed!