When I got my truck ('61 F100), I was told the transmission was "out", the previous owner told me was that he let a buddy borrow it and when he got it back the synchros were out and there was no first gear. At which point it got parked and forgotten at least 20 years ago. The linkage was stuck (column), and the drive shaft was in the bed. I pulled it today and the ID tag is rusted to the point there are no visible markings even after cleaning it up. Casing numbers are C3AR 7006-E, so I know it isn't original. Date code is 3D30. It also has a splined output shaft rather than a fixed yoke. I pulled the top and it must have gotten fairly toasty at some point, everything looks burnt and there was layer of baked oil under the lid, but the gears look ok? The shift arms(forks?) are still stuck. I am looking for any tips on how to narrow down specs so that I can source the correct rebuild kit. Tooth count, dimensions, etc. Also, while I am in here, could I switch gearing to help me out with driveability at more modern speeds once I get it on the road? It currently has a 223 and 3.89 gearing in the rear end. Thanks!
If it has a C3 casting, and a removable top cover, it’s a 3.03 fully synchronized three speed first released in 1963. They’re good transmissions, especially compared to their contemporaries. Lacking any more information, I would be looking for a kit for a 63 F100. That basic transmission was used in all manual three speed Fords with V8 engines from 63 up. Not sure, but I think big block engines got a different input shaft. I’m no expert on these, bu do know that the top loader four speed and the later four speed overdrive share the basic design, and I have rebuilt those. The three speeds never gave me any trouble, so I never had occasion to tear into one.
Thanks! I have never torn into one but from what I understand there isn't a much better candidate to learn on. Just trying to make sure I get the right parts.
When looking at the gears, it's the small engagement teeth on the side that are the concern. The main reduction teeth rarely have issues, it's the little teeth that connect and disconnect that wear out. New ones have sharp points that get rounded, then flattened with use. If worn to nubs and/or shear off, the gear is "lost".
Count the splines on the output shaft. 1964 and early 65 had 25 splines, Mid 65 went to more. Small block input shafts measured 1-1/6", 1-3/8" for some big blocks. As far as the rebuild kit, the same kit is used for the HEF, HEH, RAT, RAN, etc. The only difference is the 2-3 synchronizer size (smaller than the 1-R in some, same size in others). As @Relic Stew stated, if the gear teeth are worn out, find another transmission. Replacing the shift keys on a rebuild is also recommended. I use a short piece of PVC electrical conduit as a mandrel for the counter shaft needle bearings, and peen the oil plugs that seal the shaft . With the 223, the 3.89 gear might be a little steep, maybe 3.50 may help.
If by "modern speeds" you mean fast highway speeds, then high gear is implied. Top gear in all three speed transmissions is 1:1. So there's no way to change rpm in top gear by modifying the transmission itself.
I have a Ford 3.03 trans in my avatar roadster. It's behind a 354 hemi and has an overdrive on it. AMC used Ford 3.03 3 speeds on Jeeps in the 70s. They also used that trans in 75-77 Pacers, Gremlins, and Hornets. But with them they offered overdrive. It was a Ford 3.03 trans and a Lay**** overdrive adapted to the output shaft. I used that setup in my roadster and replaced the side shift components with a top shifter from a Jeep T 150 transmission. AMC referred the Ford 3.03 they used in Jeeps as the T150. So, what I have is a full syncro Ford 3.03 transmission connected to a Lay**** overdrive (now known as Gearvendors) and a top shifter to look old timey from the interior. ALL with factory parts! I have over 40k miles with it, all trouble free. Plus, when in overdrive, I have the advantage of a 72% overdrive! A little rare, but so far bulletproof .
I hadn't thought of the Lay**** external overdrive, that's a good point. I had been aware of them on Volvos and such in the '70s, but I would never have thought them strong enough to handle the torque of a V8. Or is the AMC unit a more robust version of the European unit?
@deucemac never seen a Lay**** out in the open but it appears to add a lot of length to the drive line. How long of a drive shaft did you end up with?
There's 2 size cases for the 3.03, the H.D unit is a little longer and will take some serious mods to the T150 top to fit and work ok. The aluminum tailshaft med duty 3.03 works great with the T150 top. I have both the HD and Med duty 3.03 and have checked the size differences.
After a light diesel wash and a little coaxing I was able to get it to move through all the gears. My intent was to fill it with diesel to let it soak some of the gunk off of it, bat as soon as it got to the output shaft it was apparent that seal was completely shot by the amount of diesel I then had running onto the shop floor.... So my guess is that it got run out of oil, no one put any work into diagnosing it and just parked it. From what I can see the teeth look good, nothing appears to be broken or ground down. I have included pics of the case as well as various shifting positions. Thanks for all the info!
Pretty easy, you just push the gas pedal down further, and go. You might find that the gearing is just about perfect, for the engine size and the weight of the truck. But what do I know....I've only driven 15k miles last year in 3.87-5.12 geared cars without overdrive, but with small engines. C8... case casting number, the 3D30 date code is probably March 30, 1973.
The Lay**** in mine is the latest and last version. If memory serves me correctly, it's what is known as the J model. It is quite tough. Gearvendors uses the same unit in RV and truck applications without any problems. The difference is (although they won't admit it) to increase the oil pressure of the pump from 500 psi to 900 psi for increased clamping action on the planets. I ended up with a drive shaft almost 30 inches long. And, as I stated before, the unit has been on the road since 2009 and ac***ulated about 40k miles and not treated with kid gloves. I would do it again without hesitation .
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