Looking for a GL4 Specific. Amsoil or Redline

[MolaKule]

"Anybody have any pictures of synchros that dissolved due to GL-5? Didn't think so!

You guys are scared about nothing. GL-4 has plenty of sulfur in it as well, and the sulfur only becomes corrosive at temperatures over 250 degrees F. How many of you get your transmissions that hot? "

Most differential and Manual Transmission oils contain sulfur-phosphorous EP packages. GL4-rated oils contain about 40% to 60% of the amount; the other difference is the Friction Modifier.

Both differential and manual transmission fluids use chemical compounds that subdue or inhibit the corrosive effects of sulfur; calcium, magnesium, boron, potassium or other basic compounds. Emulsifiers, corrosion and rust inhibitors also are included to do their respective jobs.

Differential lubes use friction modifiers to reduce mechanical and fluid friction and add some anti-shudder friction modifier for limited slip, both very different chemical compounds.

Manual Transmission fluids use a different friction modifier for synchro engagement, a modifier that does NOT contain the same chamicals as differential lubes.

 

[Towel_Rail]

Originally Posted By: Tempest
Quote:
the sulfur only becomes corrosive at temperatures over 250 degrees F. How many of you get your transmissions that hot?

Individual contact points can easily reach that temperature.


Granted, but the fluid is circulating too fast to reach that temperature itself, it is cooling the gears and redistributing that heat.

Similarly, considering the 300+ temps inside the engine bearings and the 500+ degree cylinder walls, one would think that engine oil should be coking and bursting into flame there -- but it doesn't, because it is circulating too fast for that.

And like Bruce said, there are plenty of buffer chemicals to combat the corrosion potential. The lube manufacturers aren't dummies!

- Scott

 

[Tempest]

Quote:
the fluid is circulating too fast to reach that temperature itself,

Nope, otherwise the EP additive would not work. See HERE.

Quote:
The lube manufacturers aren't dummies!

Agreed. See my post before Molakule's.

 

[deeter16317]

I thought Redline MT-90 is a 70w90, not a 75w90???

 

[unDummy]

Most oil companies have info on their websites concerning their fluid. MT90 is a 75w90.

 

[MolaKule]

"Granted, but the fluid is circulating too fast to reach that temperature itself, it is cooling the gears and redistributing that heat."

Let's remember there are two temps involved, the bulk temperature of the oil and the contact temp.

WHile temps are higher in the contact zone at the gear teeth, convection and conduction cooling are taking place.

 

[deeter16317]

Originally Posted By: unDummy
Most oil companies have info on their websites concerning their fluid. MT90 is a 75w90.


I must be thinking of their MTL...70w80.

 

[Whitewolf]

There is no simple answer. There are GL-5s that will also do synchro and there are others that are probably not such a good idea. It depends on a number of things including what material is being used in the synchro. There are 'newer' GO chemistries that may be better than some of the older ones but also there are still a large number of GL-5 fluids based on additive products such as Lubrizol's ANGLAMOL 99, which has been around for decades. The real issue is not actually one of FMs but of the surface active materials that are required in order to give gear protection in the sliding action of a hypoid axle design but also act as FMs, in certain synchro situations they may cause a problem, depending on the synchro design and materials used in the synchronizer.

 

[par]

But isn't sulfur corrosion a 'contact' issue and not a bulk property of the oil, i.e. local versus global potential. Locally, the contact may be at, or above, 250F and the fluid will cool the contact at the expense of heating up which is then dissipated through the trany casing. But corrosion will indeed take place at the contact. Maybe its more or a duration issue.

 

[deeter16317]

I was under the impression that, while at one time sulfur could be a problem, newer gear oils prevent the problems caused by sulfur by using compounds of sulfur that keep it in check? Corrosion of yellow metals isn't as much of a problem with today's lubricants, as compared to those of yesteryear.

 

[dgeesaman]

Originally Posted By: toocrazy2yoo
Is there a reason the GL5 75W90 Mobil1 synthetic couldn't work?


You've missed the point of the whole thread.

In fact, that's one of the worst GL-5s to consider because it's warns against using it in synchromesh transmissions.

Some GL-5s are synchromesh safe (GL-4/GL-5) but still don't have the same properties as a true GL-4.

IMHO, if you're going to spend $9/qt on synthetic gear oil, take your time and select the most ideal type. They all cost about the same.

Dave

 

[double vanos]

Let me check in with my Mazdaspeed 3 here.

It specs GL4 75/90 for the trans and has been plagued with a 1-2 cold shift crunch since new.

I dumped the FF and started out with Redline MT90; still too stiff!

Since Redline MTL and MT90 are miccisible I did a 50/50 blend and the shifts are so much better!!!

It has been mentioned that MTL is too thin for 75-90 spec trannie because it will not provide enough protection for the bearings.

I disagree; my 330ci has 100k on it's MTL only transmission and it is totally silent and is a paragon of shift smoothness, hot or cold.

I plan to do a straight MTL fill the next time my 'Speed3 is due for a service. We'll see how that goes, but I agree with the poster above - gear grinding shifts are a no-no.

I have no qualms about MTL's film strenghth being more than adequate for the bearings / gear tooth facings..my 330ci proves it's up to that task.

Bottom line?...try some MTL in that transmission; it may surprize you.
Cheers DV

 

[aquariuscsm]

*I plan to do a straight MTL fill the next time my 'Speed3 is due for a service. We'll see how that goes, but I agree with the poster above - gear grinding shifts are a no-no*



I totally agree on that one. Everytime I get that 1st to 2nd gear crunch,it makes me cringe!!!!!!! I was going to install the one quart of ATF today,but it was raining here and I don`t have a garage (I have to do all my auto work in my driveway). A complete RL MTL fill would be my next fill,unless the ATF/Nissan MTF works like the Zcar.com guys say it does (keeping fingers crossed!!!!!).

 

[gtx510]

vanos, your 330ci should spec MTF-LT-1 or the newer (superceded) LT-2. MTL or Amsoil MTF would be about the same thickness. google it..

your MS3 could have shifted better with the MTL/MT90 mix b/c that was the 2nd time you used Redline. iirc, they say it might take a 2nd OCI for shifting to really improve.
How long did you run the MT90 for?

I'm not an advocate of "thinner MTF is better" in hi-po cars, especially ones that call for a 90wt.
Have you guys tried stuff like rev-matching or double clutching?

 

[Bruce T]

CruzNlife1, I've tried both Mobil 1 Synthetic Gear Lube and Red Line MT-90 in my '97 Camry 5-speed manual. I can't speak for Amsoil MTG (also 75W-90 GL-4), but MT-90 shifts noticeably smoother and quieter than Mobil 1, which felt "notchy." This is driving in Oklahoma City winter temperatures vs. Palm Beach.

 

[Huhwhye]

Originally Posted By: CruzNlife1
My trans calls for GL4 (manaul, toyota tacoma 4x4) I've been using GL4/GL5 Royal Purple in is since I've had it. COLD SHIFTING SUCKS. Even in cooler florida mornings 60-70's it shifts horrible in the morning. Anyways, doing some reading, a specific GL4 fluid should be better for this transmission. Looking at Redline MT-90 or Amsoil GL4 MTF Both are 75-90 I believe and thats EXACTLY what my manual calls for. 75-90 GL4

Which is better and how much better are they than a GL4/GL5 ?? I just want it to last a long time. I drive 100 or so miles a day and plan to drive this truck forever


I have a similar vehicle, 4runner with similar needs.

What about the transfer case? What is ideal for that GL4 or GL5?

 

[double vanos]

gtx510: I ran the MT90 for about 600 miles before I cried "uncle". It was guaranteed to grind the 1-2 shift unless it was totally heated up, and I'll be dam ned, if it didn't have a distinct notchiness in all the other gears.

The tightest I'm going to run in this car is 50-50 MTL/MT90. And I am going to definetely going to give the straight MTL a shot. If it shifts anything like my Bimmer - it stays in the trannie.

 

[double vanos]

Whoops! forgot to add: no need to double clutch with the 50-50 mix; after the first 1/4 mile the cars shifts like really smooth. Only 1 caveat: if you try to shift 1-2 real slowly, or at a slow crank speed, you still get a slight grind. But push the revs up a little (say 3000 or so) and it goes right in.

Meanwhile my 330ci is: anytime, any place, any way, any temp - smooth as buttah.

 

[jbl]

Yep it is senstive to what viscosity is used. Im currently trying straight MT90 to my Volvo 5 speed XC70. So far i thinks it better compared to straight MTL.

Next replacement will be Amsoil MTG 75W90 GL4.

 

[CruzNlife1]

Originally Posted By: Huhwhye
Originally Posted By: CruzNlife1
My trans calls for GL4 (manaul, toyota tacoma 4x4) I've been using GL4/GL5 Royal Purple in is since I've had it. COLD SHIFTING SUCKS. Even in cooler florida mornings 60-70's it shifts horrible in the morning. Anyways, doing some reading, a specific GL4 fluid should be better for this transmission. Looking at Redline MT-90 or Amsoil GL4 MTF Both are 75-90 I believe and thats EXACTLY what my manual calls for. 75-90 GL4

Which is better and how much better are they than a GL4/GL5 ?? I just want it to last a long time. I drive 100 or so miles a day and plan to drive this truck forever


I have a similar vehicle, 4runner with similar needs.

What about the transfer case? What is ideal for that GL4 or GL5?


Depending on the year of your 4runner (chain driven case with ADD front disconnect like my tacoma [Newer 4-Runners too]??)

If so, the transfer case is synchronized with it's own oil pump. Also calls for a GL-4 The chain case with add disconnect can be used as a full time 4x4 (AWD) kind of. Not to be used on dry pavement but you can use it in the rain and snow up to 65 mph... And you can shift on the fly at any speed under 45 mph... I also put the royal purple in the t-case and that will be getting changed when I change the trans fluid.

Remember even if you rarely use 4x4 there are still bearings and things turning in there all the time even in 2wheel drive. And it only takes 1.1 qt so it's worth it to change it..

As far as I remember the royal purple I put in is a straight GL5 and I misread the manual. It specs a GL4 OR a GL4/GL5 I used a full GL5 thinking it would be okay. I can't wait to get the GL4 in there. Like mentioned above, notchyness best describes the way it behaves in the morning for the first 15 minutes (when I'm in stop and go traffic outside my house) I may consider the Thinner fluid (MTL?) Mixed with the proper amsoil GL4 MTG It takes 2.5 qts, I might put a quart in of the thin stuff than the other 1.5 with the proper oil.. This is NOT a highperformance truck and I'm sure it'll protect just fine.