GL5 Fluid where GL4 recommended.

Ndx

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Hey Guys, What are you thinking about using GL5 fluids in a transmission that is rated for GL4 ? Ndx
 
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It depends on the specific transmission. GL5 fluids contain EP additives that may be harmful to brass elements in transmissions calling for GL4 fluid.
 

Ndx

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Thank you... So all EP - are bad for Brass/Bronze ? Amsoil Says that the Amsoil GL5 Can be used in GL4 Boxes
 
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I would double check with one of our Amsoil regulars on the forum, like Pablo, if it'd be OK for your specific application. It just might be.
 
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 Originally Posted By: Quattro Pete
It depends on the specific transmission. GL5 fluids contain EP additives that may be harmful to brass elements in transmissions calling for GL4 fluid.
No. Anyone on this forum more than week should know that. "Excellent rust, staining and corrosion protection of copper and its alloys" "Mobil 1 Synthetic Gear Lubricant LS 75W-90 can also be used in rear axles where API Service GL-4 lubricant is recommended" http://www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil1_Synthetic_Gear_Lubricant_LS_75W-90.asp
 
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 Originally Posted By: Audi Junkie
"Mobil 1 Synthetic Gear Lubricant LS 75W-90 can also be used in rear axles where API Service GL-4 lubricant is recommended"
But we're not talking about rear axles. Anyway, if my info is outdated, please disregard.
 
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Toyota and Nissan manual trannies do not like GL5, because of yellow metals. Some GL5 will work, but check with the gear oil manufacturer if they are OK for your Toyota/Nissan.
 
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 Originally Posted By: Quattro Pete
GL5 fluids contain EP additives that may be harmful to brass elements in transmissions calling for GL4 fluid.
That's the way it used to be. The old fashioned extreme pressure additives to make GL-5 were damaging to brass & bronze. GL-4 oils had a milder add pack that didn't harm these yellow metals. Modern GL-5 additives do not harm yellow metals. If the label on the jug says that the gear oil is recommended where either GL-5 or GL-4 are spec'ed tells us that this oil is OK. And, not all GL-5 gear oils use these modern additives, so read the label.
 
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Some guy on here with a corolla 5 speed tested a bunch of GL5 oils and determined that Valvoline was better than the others including synthetics.. maybe someone can link that thread?
 
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 Originally Posted By: Ndx
Hey Guys, What are you thinking about using GL5 fluids in a transmission that is rated for GL4 ? Ndx
It's not the yellow metals (brass/bronze) - the problem is shift quality and correct FM's. Some trannies just don't shift as well with GL-5's.
 
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