SF MTL-R for my tranny (high HP, AWD)?

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BITOG is addictive. Now I'm looking for a better tranny fluid.

'94 Mitsubishi VR4 twin turbo all-wheel drive 6-speed Getrag transmission. Modified engine ~550awhp @ 20psi. recommended fluid is GL-4/GL-5 SAE75W-85W or 75W-90.

The tranny was rebuilt about 13k miles ago and has been run on a 50/50 mix of Redline MTL and MT-90. The tranny shifts OK, but it's a little notchy. Notchiest when cold, then shifting smooths out a little after warming up, but it's still somewhat notchy especially at higher rpms.

I'm looking for something to improve shift feel while still providing good protection on the track.

So far, the list of oils other owners have tried:

- Pennzoil Syncromesh: Shifts smooth but oil comes out with metal glitter. Too thin for adequate protection?
- BG Synchroshift: similar to Synchromesh.
- Redline MTL & MT-90 mix. very common, but I'm thinking there must be something that shifts better
- Redline MTL straight. Shifts well, but doesn't hold up when things get hot at the track.
- Royal Purple MaxGear 75w90. Notchy when cold, but supposedly very good when warmed up.
- Royal Purple Synchromax. Supposedly good even when cold, but maybe too thin?
- Mobil 1 10w30 motor oil. Incredibly, this is actually recommended by a tranny shop. Supposedly shifts pretty good but I'm thinking there's no way a motor oil would provide adequate protection in my tranny?

No one on the 3/S (Mitsubishi 3000GT / Dodge Stealth) platform has ever heard of Specialty Formulations that I'm aware of. I'd never heard of them until BITOG but the reviews seem pretty positive. I'm wondering if the MTL-R or MTL-P might be a good option for me or if anyone might recommend something else that might be better than the Redline MTL/MT-90 mix I'm currently using?


Max
 
A motor oil can provide plenty of protection in a transmission. But, newer SM/GF4 motor oils will not be optimum for synchro function. This is why most automakers have manual tranny fluids. If you choose a motor oil, stick with diesel HDEO's or motorcycle oils. And, a 90wt gear oil is similar to 40wt motorcycle oils.

For best protection go thickest. You have too much power for any homebrew blends. Stick with the 75w90 gear oils from RP(Maxgear), Redline(MT90 or 75w90NS), Amsoil(MTG), Motul(Gear 300), Neo(75w90hd).....

A little notchiness when cold for a longer lasting transmission is worth the sacrifice, especially if the notchiness goes away as the transmission warms up.
 
Thanks for the replies guys. Yes, I noticed the SF relocation post after I made this post.

No, to my knowledge, no one has reported any results from using Amsoil MTG. I'll try looking up some of the reviews here.


Max
 
Pablo, I noticed that Amsoil MTG is not dual rated GL4 & GL5 as the recommended fluid is.
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Trying to meet this specification is gonna be tough.
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Anyone know how long SpecForm is gonna down for? A month? Longer?
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I'd definitely go with MTL-R as my first choice for this application.

I like undummy's recommendations, overall. One of the 75W-90s would be best ... good luck finding another one that is both GL4 & GL5 rated.
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Best NOT to go with anything lighter and that rules out BG syncroshift, Pennzoil or GM syncromesh, the lighter Royal Purple fluid, Red Line MTL, etc ...

For such a high horsepower, high load application, I'd be tempted to go with Red Line Oil Shockproof 75W-90 as my #2 pick (after MTL-R). The oil is LOADED with moly to take the high loads without galling the gears. However, I'm almost positive it is a GL5 only and cold weather shifting is not gonna be as good as some other 75W-90s.
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As for your car board, they will not likely have heard of SpecForm. That's YOUR job. :flag: Try a few fluids, figure out which one is best (I'm betting MTL-R) and then YOU'RE THE MAN on your other board. I was the synchromesh fluid expert on the Nissan SpecV boards for the past few years. It took me a while but I got someone else to finally try SpecForm MTL-P in their 6-speed. Then another, then another ...

Finally, before I left (last summer), someone started a thread on 6-speed fluids and it got to two full pages before I finally posted. Why? The conventional wisdom became that MTL-P was the best for the Nissan 6-speeds calling for 75W-85 and everyone else was fianlly recommending it. Mission Accomplished.
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Bror J - Amsoil MTG is:

a) recommended for the application.
b) dual rated in the ghost mode - what I mean is: Amsoil refuses to put the GL-5 on the MTG because they don't want people using it in differentials, because it is NOT a differential fluid.

Also be careful with your words. By calling out GL4/GL5 does not necessarily mean the fluid needs to meet both. It means you can use either. And if you want to take it another step with this logic - a GL5 is just a GL4 with more additives, so all GL5's meet GL4 by default.
 
Pablo, I suppose a non-corrosive GL5 could be considered fine for GL4 applications.

I'm just reluctant to say that with a lot of cheap GL5 oils still out there. Some may still be corrosive in syncromesh applications.
 
redline shockproof would be the last thing I put in.
Its way WAY to friction modified to work properly with synchros.
 
Exactly - don't use a differential GL-5 in a transmission unless OEM recommended. Usually MT-1 indicates some safety with yellow metals. But the point is really that many transmissions don't require and shifting will suffer with a fully loaded GL-5. This is why Mits and others say GL-4/GL-5.
 
A lot of 3/S's use Redline Shockproof Heavy in the transfer case, but no one uses it in the tranny and it's not advised.

Also curious if anyone knows when SF will be back up? noticed that Molakule's last post on this board was roghly about a month ago (near when that post of SF closing for relocation was made).


Max
 
Guys, as I pointed out earlier, RL Shockproof wouldn't be my first pick for trannies but I have heard of a handful of people using it in their trannies with good results (shift quality included). Most notable was Sport Compact Car using it in a 300ZX Twin Turbo project car they built a handful of years ago.

It is recommended for some transmissions (racing, dog-ring type) but not generally for synchro boxes.

http://www.redlineoil.com/products_gearlubricants.asp?categoryID=6&subCategoryID=16
 
Quote:


A motor oil can provide plenty of protection in a transmission. But, newer SM/GF4 motor oils will not be optimum for synchro function. This is why most automakers have manual tranny fluids. If you choose a motor oil, stick with diesel HDEO's or motorcycle oils. And, a 90wt gear oil is similar to 40wt motorcycle oils.

For best protection go thickest. You have too much power for any homebrew blends. Stick with the 75w90 gear oils from RP(Maxgear), Redline(MT90 or 75w90NS), Amsoil(MTG), Motul(Gear 300), Neo(75w90hd).....

A little notchiness when cold for a longer lasting transmission is worth the sacrifice, especially if the notchiness goes away as the transmission warms up.



I don't get it.
m/c oils have more additives than PCMO's, m/c oils have more additives than HDEO's, which already have more additives than PCMO's. Most m/c oils have moly? Looking at Redline MT VOA's they have are low in additives and have no moly. Same with ATF and Synchromesh.
Seems like a PCMO without moly, like GC 0W30, would be great for the synchros?

I argee with using a SAE90 GL-4. Might even try mixing in some RL 75W140NS for those summer track days?
Tranny cooler, thermostat + Tilton gearoil pump?
 
Don't confuse 'additives' with 'additives that you can see in the VOA'. The SM/GF4 motor oils have friction modifiers usually to improve MPG. Since bikes have wet clutches, MCO's usually doesn't even though they have heavy doses of AW/EP additives that we can see in the VOA. I'll assume that those bike wet clutches will slip more with PCMO then HDEO or MCO. The opposite effect is that synchros should be less notchy with HDEO/MCO when compared with PCMO.
There is plenty in a PCMO that we don't see that make them less optimal for manual transmissions.

Also, I would also think that 0w30 or 0w40 motor oils will shear very quickly in a manual transmission.

There are plenty of good gear oils in many weights. I don't see any reason to motor oil in a manual. But, if you do, stick with an HDEO or MCO, preferably narrow number range.

Regardless, once you find a fluid that you like, change it out at a reasonable interval. 30k/2yrs is a good starting point. There is no point in pushing a fluid beyond it usefullness.
 
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