Non-EP, GL-1 gear oil - brass, synchros

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modok
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Re: Non-EP, GL-1 gear oil - brass, synchros

Post by modok »

the closest thing to "gl1" today would just be plain 15-40 or 20-50 motor oil

Id use a gear oil that is designed for a syncro trans.

Torco RTF, (top shelf!)
Valvoline MTF, (recommended by Valvoline to replace 80-90 gear oil in manual trans, I like it)
Redline mt90, (questionable longevity, but popular)

The GL ratings is a gear pressure rating, has nothing to do with if it works makes syncros work better or worse.
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Re: Non-EP, GL-1 gear oil - brass, synchros

Post by naukkis79 »

modok wrote: Wed Aug 12, 2020 8:49 pm The GL ratings is a gear pressure rating, has nothing to do with if it works makes syncros work better or worse.
EP additives are specially meant for lubricating sliding gear contact like hypoid gears. Syncromesh is also sliding contact which works better if oil don't have additives to lubricate sliding metal contacts.

-> syncromesh usually works massively better with oils that don't have EP-additives, many times it's like a crashbox becoming smooth as new with oil change from GL4 to ATF.
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Re: Non-EP, GL-1 gear oil - brass, synchros

Post by RDY4WAR »

naukkis79 wrote: Wed Aug 12, 2020 1:22 pm I do use synthetic ATF in manual gearboxes - it usually works much better than GL-4 grade oils. Redline MTL is one excellent product that have both GL4 and ATF grades but it's expensive, any thin synth ATF works usually also well.
It's pricey, but how often are you changing trans and gear oil? I change mine every 50k miles in the commuters / beaters and every 3 years in the track car.
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Re: Non-EP, GL-1 gear oil - brass, synchros

Post by autogear »

Our applications struggle with ATF. We worked with Driven Racing oil to develop a non-synthetic GL4 that would hold up with 500hp in streetable applications. It works very well and shifts smooth. Valvoline changes their additive package slightly on occasion and synchro wear is extremely short when they do.
The GL5/MT1 bronze synchro safe oils we recommend are Royal Purple MAX GEAR 75w90 (only the max gear), Mobil1 75w90LS and Amsoil MTG.

The 4 oils listed above are recommended to customers who have a warranty on their new gearboxes
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Re: Non-EP, GL-1 gear oil - brass, synchros

Post by MadBill »

AG, I assume those recommendations apply equally to factory stock Muncies?
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Re: Non-EP, GL-1 gear oil - brass, synchros

Post by RDY4WAR »

I haven't been a fan of anything from Royal Purple since Mr. Williams passed and his in-laws sold the brand down the river. Calumet let go of 95% of the staff, brought their own guys in, and that's when the problems started. They lost several contracts over the following years due to sludge issues. The standard Royal Purple engine oil you can buy off the shelf at Autozone is just a knock-off of Valvoline synthetic. The only difference is the purple dye. I haven't looked at their Max Gear recently, but I would be weary. John and his son would be turning over in their graves if they knew what's happened to their company.
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Re: Non-EP, GL-1 gear oil - brass, synchros

Post by modok »

naukkis79 wrote: Thu Aug 13, 2020 11:52 am
modok wrote: Wed Aug 12, 2020 8:49 pm The GL ratings is a gear pressure rating, has nothing to do with if it works makes syncros work better or worse.
EP additives are specially meant for lubricating sliding gear contact like hypoid gears. Syncromesh is also sliding contact which works better if oil don't have additives to lubricate sliding metal contacts.

-> syncromesh usually works massively better with oils that don't have EP-additives, many times it's like a crashbox becoming smooth as new with oil change from GL4 to ATF.
Somhow making it both too complicated and too simple at the same time.
If you want a product that works good with syncros.....use a product that says it works good with syncros. If they LIED I'd like to know. But, doesen't seem to be a problem. There is so much superstition about it I think they don't even bother to lie.

Wear and friction are NOT the same thing. Sometimes anti-wear additives reduce friction, sometimes they increase friction.
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