I'm at the part gathering stage of my RPU build. I picked up a transmission for mockup. The guy I got it from thought that it was no good, maybe was full of water. I took it anyway because it was free. Got it home , took it apart and dropped it and the shifter in a barrell of citric acid and water. It actually looked pretty good inside except for the rear thrust surface. It is scored as well as the thrust washer. Is this usable / fixable? The gears and synchros are in pretty decent shape. Most gear teeth are sharp except for 1st / reverse are a little rounded but I've seen worse.
Thrust washers for that spot come in different thicknesses. You won't know if it's past service until you set it up with what you have and find out how thick a washer you need to set it correctly. Yes, it would be nice if it was smooth, but the scores don't necessarily mean you have s**** iron.
Being an Evaporust guy, I am really impressed with the results you got with the citric acid. It looks new. I never had that kind of luck; perhaps I should re-think it. Could you possibly tell me your mixing ratios? And additives?
Maybe set that rear thrust washer up a little tight cause it will probably wear in on the back side grooves quicker? Would that be a solution?
I believe that thrust washer has a lock tab to keep it from rotating. Excessive ware lets the tab fail then it spins causing the ware. At least that's how I remember it being explained to me.
If you saw the guts of my trans you’d be horrified, they’re tougher than most think. New thicker thrust washer and good bearings and good to go, I always install a magnet in the drain plug as well.
I would lap the surface and run it.. If the washers are available in different thicknesses you are golden.
Sure changes my mine about what needs to be s****ped due to being rusty!!! From now on I'm going to de-rust before I discard(sure would have saved a bunch of money over the years!!)
29A-V8, In all the manual boxes I have overhauled (GM, Ford, and Packard to name a few) I have never seen the thrust washer lock tabs keyed in to the steel gear. I agree with Pist-n-Broke, where he says the lock tags fit in to the marks/depressions in the housing.. The steel gear is far more reststant to wear compared to a cast iron housing, hence the lock tabs would locate in the housing, with the thrust side against the hardened gear..
Having single handedly driven up the price of early ford transmissions myself I can tell you a couple of things. 1: there are around 6 different gear sets over the years, they look like they all interchange and they do on the floor but when you put them together under load however it’s a different thing. 2: surface rust on gears = case hardening gone. If your car is a parade car and barely gets driven that’s fine, if you put a lot of miles on it you’ll likely be fishing it back out again soon. and lastly 3: end play is everything in these transmissions. But as aforementioned you won’t know how much wear your thrust washer area has until you get it together and measure it. oh and speaking of thrust washers, I learned this the hard way. 40-48 gears will work in a 39 case but you have to use a 39 thrust washer with that later gear set. otherwise you’ll have a junk case in about 50 miles and your shifter will be stuck in second gear…
inthweedz. should have been more clear the front thrust washer on the cluster gear has a tab that locks in the case the rear thrust washer has 4 ****on tabs that lock into the cluster gear. The picture of the case is the rear thrust washer surface, the surface in question (this is the one that wears the most). The 4 pin thrust washer is for 1939 an up ford transmissions and should you care to check my information go to vanpelt sales, parts drawings transmissions and clutches, open Three speed transmissions for 1939 part B. you will see an expanded parts drawing showing front and rear thrust washers on the cluster gear. Part A is a side view cutout of the transmission. The older transmissions have different thrust washers, synchronizer sleeves and different gears, including the cut of the gears. hotdam makes 3 good points especially # 3 about end play both on the main shaft and the cluster gear. Some parts will interchange but you may end up with junk if you can get it to turn. I would recommend Mac Vanpelts book The Ins and Outs of Early Ford Transmissions, has everything you need to know about them.
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