Are GL4 and GL5 oil interchangeable and if not what is the difference?
GL 4 and GL5 Oil
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JimUser
Originally Posted By: jimuser
Are GL4 and GL5 oil interchangeable and if not what is the difference?
I think you are referring to GF 4 & 5 oils, not GL.
Yes, the oils are 'backwards compatible', i.e. interchangeable.
Suggest you Google the question or e.g. go to www.GF-5.com FYI.
Are GL4 and GL5 oil interchangeable and if not what is the difference?
I think you are referring to GF 4 & 5 oils, not GL.
Yes, the oils are 'backwards compatible', i.e. interchangeable.
Suggest you Google the question or e.g. go to www.GF-5.com FYI.
Originally Posted By: jimuser
Are GL4 and GL5 oil interchangeable and if not what is the difference?
No they are NOT interchangeable. In a very short nutshell
GL4 = primarily a tranny oil, some transaxles. Lower AW/EP adds
GL5 = fully additized differential oil high AW/EP additives
Are GL4 and GL5 oil interchangeable and if not what is the difference?
No they are NOT interchangeable. In a very short nutshell
GL4 = primarily a tranny oil, some transaxles. Lower AW/EP adds
GL5 = fully additized differential oil high AW/EP additives
I have not sen unbuffered GL4 or 5 for many years.
So the extra sulfur in the GL5 is not that horrible [GL4 still has 1/3-1/2 as much sulfur anyways].
But shifting is almost certainly compromised when using rear end oils in manual trannys.
So the extra sulfur in the GL5 is not that horrible [GL4 still has 1/3-1/2 as much sulfur anyways].
But shifting is almost certainly compromised when using rear end oils in manual trannys.
I'm glad I stumbled on this thread, but do have a related question. I picked up a 1986 Mazda B2000 recently with only 69K miles on the clock. Original owner all maintenance records ect. The question I have is the owners manual calls for GL4/GL5 in the tranny. It also said I only needed 2.1 qts so I picked up 2 qts of RL MT90. Well it took 2.5 qts so I had to use some leftover Valvoline Synpower gear oil I had used on the rear end. Should I do another drain and fill?
Sunny, Gear oils have come a long way in the past quarter century (the additive packs). So, that cocktail you put in your B2000, while probably not ideal, is still probably the best thing that tranny has ever seen.
I bet you're fine. I'd go at least 25,000 miles on that oil. Drain it out only if you get a wonky shift-feel.
I bet you're fine. I'd go at least 25,000 miles on that oil. Drain it out only if you get a wonky shift-feel.
Sun - Recheck your oil level on a level surface.
Tranny refills often take less than recommended [old oil clinging to parts and nooks and crannys], but I never saw one take more.
Tranny refills often take less than recommended [old oil clinging to parts and nooks and crannys], but I never saw one take more.
Originally Posted By: Bror Jace
Sunny, Gear oils have come a long way in the past quarter century (the additive packs). So, that cocktail you put in your B2000, while probably not ideal, is still probably the best thing that tranny has ever seen.
I bet you're fine. I'd go at least 25,000 miles on that oil. Drain it out only if you get a wonky shift-feel.
The tranny wasn't rough before - but it sure is smooth now! The fluid that came out sure looked nasty. I'll leave it in for a while before cahnging it. I'll also recheck the fluid level this week. I've got to replace the timing belt so I'll do it after that.
Sunny, Gear oils have come a long way in the past quarter century (the additive packs). So, that cocktail you put in your B2000, while probably not ideal, is still probably the best thing that tranny has ever seen.
I bet you're fine. I'd go at least 25,000 miles on that oil. Drain it out only if you get a wonky shift-feel.
The tranny wasn't rough before - but it sure is smooth now! The fluid that came out sure looked nasty. I'll leave it in for a while before cahnging it. I'll also recheck the fluid level this week. I've got to replace the timing belt so I'll do it after that.
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