I've developed a problem in my 28, of not being able to leave it in 2nd gear, under load it pops out, if you back off it slides back into gear position no problem, if I force the stick up it will stay there but you can feel the thrust pushing back, it had new bearings etc put in 2 years ago, so I don't think there is a problem there. The gear stick was rebuilt and all the slop of 90 years has been taken out, the selectors look great and I put in another gear box top from a good box and get the same problem though it feels different, Any suggestions, Ray
. Running with out oil will cause spur cut, non-syncro gears to hop out. Since you replaced the top, I trust you checked the oil level. If the transmission gears are worn, they will crawl out of gear when rotated. A good eye can identify a worn gear. Check both the sliding gear and counter shaft. If you hold it in gear, you'll wear out the shift forks. Try swapping with another transmission. . If it hops out of high gear, a misaligned transmission mounting where it bolts to clutch housing can cause this. . I've attached a picture of 4 cyl transmission. The 3 speed case #353300 fits 1925 model K thru 1930 model AD, if you're looking for a replacement. . . Good luck, . . Lou
Hi Lou, yes has plenty of oil, and it sits fine in the other gears, yes after 300,000 miles there is wear on all gears, I will pull out the gearbox on the weekend, I was just perplexed why this "suddenly" happened, was over the course of maybe 3 weeks, This is my work ute so I keep it well maintained and grease and oil it as per the handbook. I Have a box of spare gears so if necessary will replace the second gear. Ray
I was wondering about the detent rail I assume you have to grind off the rivets to get the plate out to see? And I use WD110 gearbox oil have done for 30 years, Ray
The 2 shift forks are part of 2 separate plates shaped to 90 degrees where the gear fork is,only the 4spd truck gearboxes use shift rails for 1st & 2nd gear,3rd & top and a separate rail for reverse.In each plate there are what look like countersink depressions.Into these,there are 2 hardened spring loaded detent plungers that are pushed into the plates by the springs.Over time,the tip of the plunger will wear a groove in the gear shifting fork plates,which will also let it jump out of gear.Check the 2nd & top sliding gear teeth for wear,as well as the 2nd gear on the cluster gear assy.Any bad wear on either or both of these gear teeth will cause the sliding gear to gradually get pushed back out of mesh.
Ill take pics when i pull the gearbox out on the weekend, I do have a NOS 2nd gear in my bits still in its grease paper, I assume if I use this, I will have to lap in the gears a bit before putting into service? I do have an old greasy gearbox under the shed,unknown quantity and bound to need new bearings etc, but if all else fails I'll have to rebuild it, Ray
If you put a new 2nd & top sliding gear to work against a worn cluster 2nd gear,you'll possibly have the same problem.If the cluster 2nd spd gear is worn,try disassembling the cluster gear assy,grind & dress new "leads" on the opposite ends of the teeth and re-install it in reverse,so that the un-worn gear teeth faces run on the new 2nd & top sliding gear faces.
