Redline lightweight shockproof?

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bccentaur3

New member
So I see that redline mt-90 works well with out cars, but I did some reading on mr2oc and it seems as if they like the lightweight shockproof stuff. So I guess its 75w80 and not the 75w90 that toyota calls for, but how well would it work on our cars? When I put my car together I got some cheapo gear lube, since I was running low on my budget for the build and figured I can drain and refill when my income starts to stabilize. So should I go ahead and buy some mt-90 or the lightweight shockproof stuff?
 
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MWP

New member
Shockproof may make your shifts feel awesome (the reason most people like it), but itll cause bearings to wear quicker.
Ive also heard of shockproof causing the synchros to become glazed over time and cause bad shifting.
Shockproof isnt designed to be used in gearboxes, its mainly for diff use.

MT-90 is what you need to use.
Unlike shockproof, MT90 is made specifically for gearboxes.
I changed from Castrol Synth to MT90... huge difference, MT90 is awesome stuff!
 
C

Corey

Active member
In what way? I understand GL-4 is better for syncros, but have been told it lacks the same protection of GL5 for the differentials in our transmission :shrug:

I would love to be able to use a GL-4 to improve shifting, but from what I understand, it may come with lesser diff protection?

Thanks
 
M

MWP

New member
MT-90 is actually quite thick... so good for bearings & diffs.
It being thicker is also what Redline claims gives better shifting.

Its also Redlines full synth oil which is many times more shock & wear resistant than normal oils.

Your in North America, why dont you just give Redline a call and ask them?
 
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Corey

Active member
I called Redline a few months ago - as summarized in the Tranny oil thread.

viewtopic.php?f=43&t=19619&start=45

In an application that allows either a GL-4 or a GL-5, 75W90 viscosity we recommend the MT-90. If your factory owners manual does specifically call for a GL-5, I would recommend the 75W90NS.

Some GL-5 gear lubes can be corrosive to brass, bronze or copper also many are too slippery for the synchros. Our GL-5 gear oils don't contain sufficient EP additives to be corrosive, the "NS" fluids are designed to provide good shiftability with the proper coefficient of friction for the synchros.

Regards,
Red Line Oil
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It being thicker is also what Redline claims gives better shifting.
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I don't think that is what they claim. MT-90 Shifts better because it does not have the same Shock protection additives as the 75W90

Also, according to the charts on their site - both the MT-90 and the 75W90NS have the same viscosities at 100*C and the 75W90NS is actually a bit Thicker than the MT-90 at 40*C

From what I understand, the "thickness" of the oil is not the defining factor of gear protection - its the quantity of shock protection additive in the oil.

Redline 75W90 Gear oil has the most
Redline 75W90NS is a comprimise - designed for use in gear boxes like ours.
Redline 75W90 MT-90 is a GL-4 which does not have the same shock protection additives. This means it is great for shifting and syncros, but not necessarily good for diff protection.


If someone has some sort of evidence or personal experience showing that GL4 is perfectly safe in our transmission, I would try it immediately because I would expect smoother shifts from the GL4 vs GL5 which is recommended by toyota - and redline for that matter when i last e-mailed them.
 
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Corey

Active member
So I see that redline mt-90 works well with out cars
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Don't suppose you have a link for this info?

Does anyone have some information on how GL4 affects our gear boxes? I really am interested in using it, if its not going to compromise protection of another area of the gear box just to make it shift smoother.

For instance - for anyone running GL4, how long have you been running it? Any adverse affects noticed thus far? What kind of power levels?

I know there are threads on this on MR2OC. I've been through a couple of them - and I found they basically came down to a couple owners debating back and forth with no solid conclusion or data.

Thanks

Corey
 
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Corey

Active member
Im not sure :shrug:

Sounds like the cars on that forum are RWD? So no Hypoid differentials to worry about in the first place.

Any news about using MT-90 in our gear boxes besides simple opinions? Redline's site says GL4 is not recommended for Hypoid gears, which are used in our transmission's differential.

I'm doing an oil change in the next week, and was hoping for some updates on this subject before I go pouring some GL4 in my tranny only for it to be under protected.

Thanks
 
S

Simba

New member
I've been running MTL in mine for ~40k with zero issues and silky smooth shifting. I run it in just about everything I own.
 
C

Corey

Active member
That's good news :)

May I ask why MTL vs MT-90?

EDIT:

Found this on Wiki: Seems to state that if the Hypoid gears have a Small displacement of Axes, then GL4 is sufficient.

Does anyone know if the Hypoid differential in our transmission falls under this category?

API GL-4, oils for various conditions - light to heavy. They contain up to 4.0% effective antiscuffing additives. Designed for bevel and hypoid gears which have small displacement of axes, the gearboxes of trucks, and axle units. Recommended for non-synchronized gearboxes of US trucks, tractors and buses and for main and other gears of all vehicles. These oils are basic for synchronized gearboxes, especially in Europe.
API GL-5, oils for severe conditions. They contain up to 6.5% effective antiscuffing additives. The general application of oils in this class are for hypoid gears having significant displacement of axes.
Click to expand...
 
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Simba

New member
Corey Darling":uz6ltlba said:
May I ask why MTL vs MT-90?
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MTL is slightly lighter weight than MT-90. Helps the box shift smoother when it's cold, and I haven't noticed it wanting for a thicker weight when hot, so I prefer it.
 
C

Corey

Active member
Fair enough, Thanks :)

I think I'm going to give MT-90 a try in the Tranny, and the usual 75W90 in the differential (or maybe heavy shockproof).

Or I'll chicken out and do a mix of MT-90 and 75W90NS of some kind, but I'll probably check with redline first to see if that even makes sense.
 
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Corey

Active member
Just filled the transmission with MT-90 and re-filled the diff with 75W90 again.

Noticeable difference with the MT-90 in terms of shift smoothness, especially from 3rd to 2nd on my E154F tranny which was pretty notchy before without double clutching.

So I'm pretty happy with it thus far, I just hope it doesn't hurt anything in the long run :|
 
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