slowly working on my 61' Apache 10 (short-step). Had my 4-speed rebuilt by a local transmission shop and after the engine was re-built, I installed it in my truck. Over time driving it (short distances) while I work on it, I noticed that the shift up from 2 to 3 would sometimes grind going into 3rd. I can downshift from 4 to 3 with no grind and it seems to happen at higher speed shifts compared to shifting 2 to 3 earlier and at lower overall speed.
Clutch is working, had a local shop check my work on the clutch master and they even rebleed it and made an adjustment, but it will still occasionally grind 2 to 3.
Every other gear and reverse seem to be what I would consider normal. I start from a stop in 2nd almost all the time. Truck is running and driving well except for this issue. I am past the year warranty on my 4-speed rebuild (it was a carry in as I had the front off the truck at the time) and I suspect my problem is with the 3rd gear synchro.
Anything you would recommend or what am I missing? Thanks - gpk1961 Frisco Texas
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
What are you using for fluid in your transmission? No synthetic!
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
GPK1961 If not a synthetic oil problem would suspect a burr on the brass synchronizer ring,or a well worn 3rd gear. Might take off you pto cover and look to see if brass ring is too close to 3rd gear . Also if shift collar detents are kinda weak not putting enough tension on ring,slips in too easily. Should be able to feel that thru your stick. I guess you don't know if that is a new synchronizer ring?? My 2-ton 48 does that too pretty sure it's weak detents,gotta make me tear it out of there and put in some meaner detents !!
Thanks for the response. I used gear oil that was not synthetic (I checked here first!) I will check the trans oil and add if needed. I do notice some noise if I leave my hand on the gear shift that I don't remember. It goes away when you let go. I am careful shifting, leaving the clutch engaged a bit longer and making sure I'm all the way to the floorboard and I still will get an occasional grind... I have plenty to do on this truck and I can still move it around. I need to re-wire it and then I will mess with the tranny. Thanks again - stay cool! gpk1961
I would take the truck back to the transmission shop. Explain the problem. You don't want to let any warranty pass you by. I'm not up on the SM420 but it could also be a problem with the shifter fork or related part. It doesn't hurt a thing to discuss the problem.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
