I'd largley ignore the API rating and just look specifically for a manual transmission fluid in the viscosity you require. Some MTF's are indeed GL-5 rated lubes and can be used perfectly well in a manual transmission.
Some, but few are and usually for special applications such as common sump transaxles and HD trucks....Some MTF's are indeed GL-5 rated lubes and can be used perfectly well in a manual transmission....
I am not sure that RedLine 75W85 is Hyundai & Kia approved, or that Redline has approvals by them.I used the OEM spec GL-4 Synthetic RedLine 75W85 fluid that is Hyundai & Kia approved in the manual transmission and it really does feel better.
okay its "recommended" for Hyundai kia, and a few others. My wording was off. I should of said recommended.....I am not sure that RedLine 75W85 is Hyundai & Kia approved, or that Redline has approvals by them.
Your choice of viscosity may be correct, but approvals?
So if it shifts better that is good.
Some, but few are and usually for special applications such as common sump transaxles and HD trucks.
GL-5 fluids have a different chemistry and base oil mix than do GL-4 MTF's.
Don't assume because they are both "gear" oils that one can be substituted for another.
Most vehicles and light duty trucks with MT's specify GL-4 MTF's.
If in doubt, take a sample, have it analyzed, and post it here on BITOG so we can attempt to match it up.
Gear & Transmission Used/Virgin Oil Analysis
Virgin and Used Gear & Transmission Analysis reports.bobistheoilguy.com
What is the 40C and 100C Kinematic Viscosity of this fluid in cSt.? 75W80 tells us nothing but the 'range' of possible viscosity.That's why I was quite specific that it had to be an MTF.
I use Fuchs Sintofluid 75w80 as a universal oil for most manual gearboxes. It's a GL-5 lube despite being an MTF.
TITAN SINTOFLUID SAE 75W-80 | Automotive lubricants | FUCHS LUBRICANTS (UK) PLC
Premium Performance Manual Transmission Fluid for passenger cars. Offering good gearbox efficiency. Suitable as fill for life fluid according to manufacturer.www.fuchs.com
Are you referring to the Eneos? They say very definitely it is ok. It’s in the link. Made in USA. My vehicle,Toyota T100 with W59 trans says use gl4 or gl5. But I decided this is safer than one that says gl4 alone, as it specifically states compatibility in writing. Since I saw Valvoline says gl4 but also not for synchromesh, I said wait a minute here.-
Which vehicle? I wouldn't use this oil in any synchronized transmission.
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Is yours a hypoid transmission?Are you referring to the Eneos? They say very definitely it is ok. It’s in the link. Made in USA. My vehicle,Toyota T100 with W59 trans says use gl4 or gl5. But I decided this is safer than one that says gl4 alone, as it specifically states compatibility in writing. Since I saw Valvoline says gl4 but also not for synchromesh, I said wait a minute here.
Are you referring to the Eneos? They say very definitely it is ok. It’s in the link. Made in USA. My vehicle,Toyota T100 with W59 trans says use gl4 or gl5. But I decided this is safer than one that says gl4 alone, as it specifically states compatibility in writing. Since I saw Valvoline says gl4 but also not for synchromesh, I said wait a minute here.
Did you read what the bottle says? compatible with synchromesh , and further enables easy and smooth shifting in low temps. Do you think they are talking about easy and smooth rear axle gear shifting?Yes, I refered to the Eneos. Just being 'ok' doesn't sound like a perfect match to my ears.
They don't mention 'suitable for W59 transmissions' or similar. That would be 'definitely'.
I don't get why you think GL-4 AND GL-5 simultaneously would be anything superior in
your longitudinal manual transmission as it most definitely doesn't use any hypoid gears
at all (unlike your rear diff). I have abolutely no experience with this W59 transmission, so
take this with a grain of salt, but in the vast majority of similar cases a GL-4 only MTF is the
most appropriate fluid. I think waiting a minute was a good idea.
The back of the bottle says compatible with synchromesh. This takes away the yellow metal worries. Then it says our proprietary tech enables easy shifting. That’s my end of specificity needs..
I've read the entire product description. Bottle says 'LSD gear oil' and
'LSD, GL-5' on front. I'd say this makes me pondering, to say the least.
I'm sure I'm not a person who comments inconsiderately on a subject.
I'd suggest to compare this product data sheet to others to get a feel
about the differences in the wordings.
.