Best lubrication for transmission ?

Lucas oil stabilizer makes a huge difference in how the transmission feels. Gives the gearshift a silky smooth feel. Night and day difference over 600w. Several years ago I changed out the transmission fluid with new 600w, didnt feel any difference over the old goo that had been in there for who knows how long. Ran it for a while but then tried lucas. Amazing difference.
 
It would be interesting to see what the viscosity of the off the shelf 600w is at operating temperature.I do know foaming in an issue.STP and other additives are not tested for pressure,in other words,even though its thick it might not handle the tooth on tooth contact pressure of engaged gears under load,possibly ending up with accelerated wear.That's where the API designation is critical,it tells you,by testing, how the oil handles the actual condition its under,way more scientific than looking at it and approving it by how thick it is.
 
Muskets served us well till the rifled barrel was developed...grasping new technology and understanding its value helps keep the car alive.
 
Terry said:
The transmission is one thing while the rear end is another! What works in the transmission may not work well in the rear end. Frsintance, the rear gears are in constant mesh and don't have shifting issues. So why can't we use a lighter oil and reduce some of the internal resistance. I frequently notice that model A owners will use the same lubricant in both the transmission and differential. I'm not saying this is wrong, but you're dealing with two different mechanical systems with different needs.
Terry
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That is what is behind my thinking too. I'd expect using the more modern oil might give longer life and slightly improve performance because there is less drag in the diff. I also agree with what you say about not using anything more than GL1 with bronze bearings or bushes. The sulphides in those oils eat bronze.
 
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The Model A parts suppliers are not in the lubrication industry. They are not formulating or making the oil. They do commonly re-package the lubricant from bulk and place their label and name on it for sale. Many of the modern lubricants are harmful to old gear boxes and differentials because they will destroy bronze bushings, thrust washers, or spacers, anything made of brass or bronze. Most modern equipment doesn’t have any bronze parts so the new lubricants are fine for modern equipment. However, there are lubricant companies that do make excellent modern lubricants for Model A, AA, Ford transmissions, gear boxes, and differentials. Lubriplate makes SPO-288 which is perfect for Model A, and AA transmissions, steering boxes, and differentials. There are other companies that make similar products, but Lubriplate SPO-288 is my choice.
 
Absolutely correct about lubrication needs for modern helical gears are very different than lubrication needs for spur gears. (Apples and Oranges)
 
Except for the 2 bronze thrust washers in the 1928 transmissions and reverse idler gear brass bushing used all years, there is no brass/bronze to worry about in the stock A transmission or rear end.
 
redmodelt said:
Except for the 2 bronze thrust washers in the 1928 transmissions and reverse idler gear brass bushing used all years, there is no brass/bronze to worry about in the stock A transmission or rear end.
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Replace those thrust washers with hardened steel ones and you'd be fine with an EP oil but I still wouldn't do it. I think the thinner oil would make changing more difficult.
 
vonheine said:
Many of the modern lubricants are harmful to old gear boxes and differentials because they will destroy bronze bushings, thrust washers, or spacers, anything made of brass or bronze.
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I've heard this rumor for years, so a number of years ago, for an experiment, I put a bronze synchronizer ring in a glass jar w/90-140 gear oil and let it sit for a couple of years and nothing happened to either the ring or the oil.
 

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Noting will happen just sitting in a jar. What happens is, the additives bind at the molecular level with the brass and as the steel parts rub they are sheered off taking the brass with them.
 
Getting down to the molecular level,synthetic blends have consistent molecule size,where 'dinosaur' oil the molecule size is random.This basic difference is what makes synthetic oils superior to dino oils,chaining viscosity modifiers and load additives to synthetic oils is precise,leading to less 'oil breakdown',the breakdown of the additives bind to the molecule. That,plus the lower friction associated with consistent sized molecules is why synthetic oils are superior.
 
I am working on a 1930 AA truck. The differential has a brass thrust plate that the ring gear pushes against to prevent the ring gear from wobbling in the case when it’s torqued up under a heavy load. Also, depending upon what parts are available, there are spiders gears for these trucks that use 4 bronze shims under the pinions. (BB parts, suitable for use) The AA four speed uses a bronze bushing on the reverse idler gear. This is why I am avoiding lubricants that attack yellow metals.
 
vonheine said:
I am working on a 1930 AA truck. The differential has a brass thrust plate that the ring gear pushes against to prevent the ring gear from wobbling in the case when it’s torqued up under a heavy load. Also, depending upon what parts are available, there are spiders gears for these trucks that use 4 bronze shims under the pinions. (BB parts, suitable for use) The AA four speed uses a bronze bushing on the reverse idler gear. This is why I am avoiding lubricants that attack yellow metals.
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I do the same for my Model A's and Studebakers.
 
How do you know a certain lubricant has additives that will attack yellow metals?

I found the Copper Strip ASTMD130,3hrs@ 100oC for the gear oil I am using to be 1B which is light tarnish. It took a lot of digging to find it . It’s not somthing you find when you go shopping at Autozone for gear oil.
 
The GL-5 issue is with bronze synchronizers.The merits of high pressure high load GL-5 far outweigh the potential issue,which is non existent in a model a.Current GL-5 has been buffered to eliminate this rare issue..but hey,I use modern sealants and engine oils too..
 
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