Transmission fluid has been a topic many times however I don't recall any mention of syncromesh or synthetic oil. I have a 49-3100 4 speed and a few times I can feel slight grinding from 2 to 3 and 3 to 4. Would either syncromesh or synthetic oil help?
More than likely your synchronizers are worn and no lube will cure that but I have seen too heavy of lube cause gears to scratch. Some modern manual trans use ATF for fluid and if some dummy (this hits close to home) fills with 90wt the trans won't shift at all when cold.
Doug, this will conflict with Evan's post, but here goes. 90W gear oil is what was supposed to be used in the SM420's. It is hard to find, so some people use a multi-grade such as 80W-90. I have heard, but cannot verify, that the multi-grades have ingredients that are detrimental to any brass parts that are in the tranny. I stick to straight 90W in both my tranny and my Eaton HO52 rear end and have no issues.
As hard as it may seem to find, it is under all of our noses at Walmart. Go to the marine section in sporting goods. Look for Quicksilver (Mercury) High Performance 90W lower unit gear oil. It isn't cheap at about $10 per quart, but you don't need much. They also sell a Quicksilver Premium multi-grade 80W-90 gear oil...don't buy that. Here is a link--
Any other gear oil other than straight 90w mineral based oil will cause the synchronizers to clash. The ash content in the modern multi- grade gear oil is too low, which causes the synchronizers to slip and not engage the gears correctly. Ford tractor straight 90w is GREAT. Napa also carries a 90w straight mineral based gear oil, but you will need to ask one of the people behind the counter for it. The bottles will probably have a heavy dust layer on them. Don't think this stuff is a hot mover.
"Pay attention to the details! It ALWAYS pays off."
1949 Chevrolet 3100 Series 1/2 ton Pickup 1964 Chevrolet C10 (Ol' Yella) (SOLD) 1958 Chevrolet Biscayne 2 door (SOLD) 1970 VW Beetle
Ditto on all of the above. Hypoid gear lube is for rear ends- - - -not transmissions, as it contains high film strength additives intended to deal with the loads of spiral bevel gears that mesh below the centerline of the ring gear. If lubricant in a transmission is too slippery the synchronizer rings can't get a grip on the cone clutch part of the gears to match the speed as the synchronizer collar meshes with the gear. Mineral oil only is also needed in Fuller Roadranger twin countershaft transmissions. Hypoid gear lube causes carbon deposits to build up on the synchronizers and makes them fail prematurely. I visited a Fuller repair depot in San Francisco once where they had 55-gallon drums full of ruined brass synchro blocker rings. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Yes, just about all older manual transmissions need mineral oil, not hypoid lube. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
This summer during the build I filled my transmission and rear differential with 80-90 gear oil. I guess I'll have to drain them and get the trator supply 90w stuff. Hopefully I haven't screwd something up in there.
1950 SUBURBAN / SCHOOL BUS A.K.A "THE SCHOOL RUST"
Run- - - -do not walk away from Amsoil! It's synthetic, and so slippery the synchronizers won't work well at all. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I got up this morning and drained the transmission. I'm going to cycle through some 90w mineral a few times over the next couple of months. From what I've heard, the 80-90 stuff should be ok to leave in the rear differential. Right?
1950 SUBURBAN / SCHOOL BUS A.K.A "THE SCHOOL RUST"
Yes that lubricant in the diff is ok just get it out of the transmission. Your thought of one or two purge and refill should work fine, If you can drive it after the first refill and then drain when the oil is warm it will drain out better. Let it drip out overnight.
Your transmission thanks you for reading StoveBolt forum!
Doug, this will conflict with Evan's post, but here goes. 90W gear oil is what was supposed to be used in the SM420's. It is hard to find, so some people use a multi-grade such as 80W-90. I have heard, but cannot verify, that the multi-grades have ingredients that are detrimental to any brass parts that are in the tranny. I stick to straight 90W in both my tranny and my Eaton HO52 rear end and have no issues.
As hard as it may seem to find, it is under all of our noses at Walmart. Go to the marine section in sporting goods. Look for Quicksilver (Mercury) High Performance 90W lower unit gear oil. It isn't cheap at about $10 per quart, but you don't need much. They also sell a Quicksilver Premium multi-grade 80W-90 gear oil...don't buy that. Here is a link--
JW51's post is why I have stayed away from using the Tractor Supply mineral oil in my Eaton H052 rear end. I'm no rear end expert and no oil expert, but literature available from the GM Heritage Center states that the Task Force rear ends except for the real, real big trucks are all hypoid rear ends. So that's why I never bought the stuff before and stuck to the 90W Quicksilver High Performance Gear Lube. Now, for all I know, the Quicksilver stuff is also mineral oil, but not that I have been able to tell from the Mercury literature.
That being said, I was at Tractor Supply over the weekend and bought a jug of the 90W mineral oil! I guess I'll save that for trannies and stick to the Quicksilver 90W in the rear ends until someone has better advice.
What effect does hypoid gear oil have on the u-joint in an enclosed driveshaft? Is it necessary to drain/refill the ball when changing to mineral oil lube?
JW51's post is why I have stayed away from using the Tractor Supply mineral oil in my Eaton H052 rear end. I'm no rear end expert and no oil expert, but literature available from the GM Heritage Center states that the Task Force rear ends except for the real, real big trucks are all hypoid rear ends. So that's why I never bought the stuff before and stuck to the 90W Quicksilver High Performance Gear Lube. Now, for all I know, the Quicksilver stuff is also mineral oil, but not that I have been able to tell from the Mercury literature.
That being said, I was at Tractor Supply over the weekend and bought a jug of the 90W mineral oil! I guess I'll save that for trannies and stick to the Quicksilver 90W in the rear ends until someone has better advice.
Good discussion...thanks,
Matt
From what I've found, the high performance is synthetic, and premium is not. But I can't confirm for sure
First changed the trans and diff lube 18 years ago when I bought the truck. Used Quaker State 80-90 in both. Used it again when I changed the oil in the trans after doing an Okie install. Changed the diff oil when I changed the cover gasket. Used 80-90 in all cases. My tranny leaks so when I top it up I use the same oil. Everything is fine until I started reading this thread. Its still fine but now I am questioning myself. One thing I stay away from is Lucas oil.
1949 Chevy 1/2-Ton "Sedgewick" In the Gallery 1989 Caprice
I found my notes from about five years ago when I first went on a hunt for 90W non-mineral gear oil and couldn't find any at my local auto parts stores. I was changing the pumpkin in my Eaton from a 4.56 to a 4.10 at the time, so I knew that I'd need the right stuff to refill it.
I called Mercury Marine to check on the Quicksilver 90W. It is not synthetic, but it does have synthetic additives. It is made for higher horsepower marine lower units with hypoid gears. The synthetic additives are introduced to improve the load limit capability of the oil. It does not have anything in it that will hurt brass parts. It is NOT to be mixed with 80W-90 lower unit lube. The 90W is designed for lower units that will have more of a load on them. The only reason that I thought about this product is that I remembered my marina used to buy it by the 55 gallon drum.
I found this thread interesting, so I did a little more research. Automotive gear oils have a GL rating; marine gear oils are not required to. It turns out 90W gear oils are not all the same. Some are mineral, some are not, some are synthetic, some have synthetic additives, some can hurt yellow metals. Even within categories there are different GL ratings. GL might stand for 'gear load' because the higher the rating, the higher the rated gear load. Here is a link to a quick read that others might find interesting-- https://en.wikipedia.org/wiki/Gear_oil There is lots more info readily available on the internet if you want more detail.
It seems that the best solution for both trannies and hypoid rear ends would be a non-mineral SAE90 gear oil with a GL-4 rating. GL-5 would have a higher load rating, but the additives used to achieve that load rating can be detrimental to yellow metals, so GL-4 seems to be the ticket. Gear oils rated below GL-3 are not listed for hypoid gear applications.
I found a 90W non-mineral, non-synthetic GL-4 gear oil made in the USA and marketed under the name Lube King. It is priced right at $29 delivered for a two gallon jug, not too much more than the Tractor Supply mineral oil. I bought a jug. This is what I plan to use going forward in my SM420 and Eaton rear end.
Getting back to the Quicksilver product, it is probably comparable to an automotive gear oil rated as a GL-4 based on the description, but that is simply an interpretation on my part. It does not have a GL rating. I will start using the less expensive Luke King product. I'd use the Quicksilver again if I couldn't find the less expensive alternative. My local Walmart has the Quicksilver for $13 per quart. That's $104 for two gallons compared to $29 for the Lube King product. Sounds worse than it is because it only takes about 3 1/2 quarts, as I recall, to change out both the rear end and the tranny.
I also found a comparable Citgo product, but it was only available in 5 gallon pails. NAPA also has a couple options that you can find if you type SAE90 into their search engine, but they are also only available in 5 gallon pails...and they carry a 5 gallon pail of SAE90 mineral oil.
I have found this to be a very interesting thread and thank all who have contributed,
If it's non-mineral and non-synthetic, what in the world is it? I was under the impression that almost any oil was either one or the other, or a combination thereof?
To give another perspective to some of the comments here. I have been using and selling Amsoil synthetic oils for over 30 years. Back in the 70s, we commonly replaced the 90 weight oils in transmissions with 20W-50 racing oil, which has additives to prevent galling. It worked excellently in everything from VWs and BMWs, some of which are notoriously difficult to shift into 1st while on the move (particularly when cold), to 60,000+ GVW transport trucks. In the trucks that hauled over one particularly long adverse grade, the transmisson temperature typically was 50 degrees lower after switching to the synthetic, and in one case, it dropped the transmission temperature 70 degrees. Another excellent use for this oil, was in the older transmissions and transfer cases. It improved shifting dramatically. The newer vehicles that use the ATF as the filler, can still benefit from switching to a synthetic ATF. It will run cooler, shift better, and run quieter. Every piece of equipment I own runs on synthetic oil including my airplane. Bob
55 Cameo 396 TH 400 with overdrive 65 Caliente conv 67 BB Caliente conv 67 Mercury 1 Ton 76 GMC 3/4 ton 454ci 84 Buick Turbo Regal
I found my notes from about five years ago when I first went on a hunt for 90W non-mineral gear oil and couldn't find any at my local auto parts stores. I was changing the pumpkin in my Eaton from a 4.56 to a 4.10 at the time, so I knew that I'd need the right stuff to refill it.
I called Mercury Marine to check on the Quicksilver 90W. It is not synthetic, but it does have synthetic additives. It is made for higher horsepower marine lower units with hypoid gears. The synthetic additives are introduced to improve the load limit capability of the oil. It does not have anything in it that will hurt brass parts. It is NOT to be mixed with 80W-90 lower unit lube. The 90W is designed for lower units that will have more of a load on them. The only reason that I thought about this product is that I remembered my marina used to buy it by the 55 gallon drum.
I found this thread interesting, so I did a little more research. Automotive gear oils have a GL rating; marine gear oils are not required to. It turns out 90W gear oils are not all the same. Some are mineral, some are not, some are synthetic, some have synthetic additives, some can hurt yellow metals. Even within categories there are different GL ratings. GL might stand for 'gear load' because the higher the rating, the higher the rated gear load. Here is a link to a quick read that others might find interesting-- https://en.wikipedia.org/wiki/Gear_oil There is lots more info readily available on the internet if you want more detail.
It seems that the best solution for both trannies and hypoid rear ends would be a non-mineral SAE90 gear oil with a GL-4 rating. GL-5 would have a higher load rating, but the additives used to achieve that load rating can be detrimental to yellow metals, so GL-4 seems to be the ticket. Gear oils rated below GL-3 are not listed for hypoid gear applications.
I found a 90W non-mineral, non-synthetic GL-4 gear oil made in the USA and marketed under the name Lube King. It is priced right at $29 delivered for a two gallon jug, not too much more than the Tractor Supply mineral oil. I bought a jug. This is what I plan to use going forward in my SM420 and Eaton rear end.
Getting back to the Quicksilver product, it is probably comparable to an automotive gear oil rated as a GL-4 based on the description, but that is simply an interpretation on my part. It does not have a GL rating. I will start using the less expensive Luke King product. I'd use the Quicksilver again if I couldn't find the less expensive alternative. My local Walmart has the Quicksilver for $13 per quart. That's $104 for two gallons compared to $29 for the Lube King product. Sounds worse than it is because it only takes about 3 1/2 quarts, as I recall, to change out both the rear end and the tranny.
I also found a comparable Citgo product, but it was only available in 5 gallon pails. NAPA also has a couple options that you can find if you type SAE90 into their search engine, but they are also only available in 5 gallon pails...and they carry a 5 gallon pail of SAE90 mineral oil.
I have found this to be a very interesting thread and thank all who have contributed,
Matt
Thanks for the info, the Quicksilver here doesn't list the weight or GL on the bottle. The Mercury brand however does, 90W and GL-4. That might be the easiest fluid to get around here for the trans. I did come across Lube King on Walmart Canada's site, but they want to charge shipping which doubles the price - probably still cheaper by volume than Mercury. Quicksilver is not available on their Canadian website.
