vermontoyota

I changed the manual trans lube in my truck to Amsoil Sever-Gear 75-90. It is GL-5. It was a pretty goofy looking process - no syringe or pump so I used 1/4" tubing and rigged a hopper to my sideview mirror and waited. and waited. It worked but took a while to get all 3.7 qt in!

My review of the product is this: Once up to temperature it shifts smoother than before. 3rd gear was always a bit rough, nothing serious and no grinding, but it shifts smooth now.

The wierd thing is, when cold, it shifts like a BEAR. 2nd goes in super hard, and will grind if I'm not careful. Double clutching (or just shifting late) helps, but shifting around the 2250-2500 mark I usually shift at is really tough until the engine has been at operating temps for a few minutes. It is cold here, but even when its been hovering around freezing it does it - unexpected for a 75w.

I called amsoil tech dept and they had no good answer and said that it's probably the way the tranny shifts but it had been smoother before because the conventional lube molecules had experienced excessive shear (I think of shear as something that happens in beams, but I've heard this term used for lubricants). Not sure I buy that - this thing shifts pretty rough when its cold.

I did spill a whisker in the above mentioned cobb-jobb process of filling it so maybe it just needs to be topped off....Hard to believe a fraction of a qt would cause that though.

Any thoughts?

Stuwy123

iTrader: (1)

When oil gets cold, the viscosity goes up (i.e. thicker).
When oil is warm (after running for a few minutes), the viscosity goes down (i.e. thinner).

When the oil is thick, it's hard to feel when it's in gear.

Try shifting when your truck has been sitting in -35C overnight.
Sometimes the shifter doesn't even re-center itself.

vermontoyota

I understand that. I have no problem feeling that it is in gear, Its tough to actually get into gear.

I dont know what -35C is but I've driven the truck in -20F when it had stock lube and it shifted better than it does now at 32F.

What is it like 9/5*C+32=F? So I guess I have never tried to shift it at -35..but pretty close.

RustBucket

iTrader: (1)

Maybe when they said your old fluid had "experienced excessive shear" they just meant it was broken down.

Was your old fluid a GL-4 or GL-5? I just installed GL-4 Sta-Lube and it's been very good. From what I understand the friction modifiers in a GL-5 don't help the synchros to grab correctly - hence harder shifting.

JJ'89

Sorry to hear about your situation. Sounds like you were trying to "upgrade" for better "performance" whatever that is. I take it that Amsoil is synthetic. I'll bet your factory manual specifies GL-4. Synthetic will flow at a lower temperature; that's part of what you're paying extra for. GL-5 has friction modifiers or some such to work with limited-slip differentials. Don't work so good in synchromesh transmissions which depend on friction to synchronize.

Forgive me for sounding like a grouchy old man, but if you are believing everything you read in the magazines or see and hear on TV (or even 5% of it) you're a sucker. Lot of rich people because of multitudes of suckers. Muffler companies, air filter companies, specialty oil companies, etc. they all got a pitch and 99% of it is hype and b.s.

I was reading one yesterday, guy has a Dodge pickup, claims his new KN filter increased gas mileage 2 mpg. Hah that's a good one. The car companies would die for an easy 2 mpg in their hassles with the EPA. If it worked, they'd be doin' it. Many more example like that. What does "up to 20%" mean? That's right, anything between 0.0000000% and 19.9999999%. No lie; just B.S.

My advice: get a factory owner's manual and shop manual and do what they say. If it was mine, I'd drain the Amsoil gear oil out and put in Sta-Lube GL-4. Why Sta-Lube? cause' I got a jug I bought last year for my Roto-Tiller. If I needed to buy some more I'd hustle down to the hardware store and get another jug. Most parts places probably don't carry GL-4, lack of demand. Manual trans and diff gear lube very rarely needs to be changed. Like my old owners manuals for 60's and 70's GM and Mopar said "good for the life of the axle" unless severe duty (towing, etc) application.

End of rant. Good Luck.

vermontoyota

Sorry cheif, GL5 is fine per the factory manual.

ASTM is the authoritative body in far more than roto-tillers. Their tests and standards are adopted as legal measure for performance. When I'm at work a lot of the specifications I hold concrete contractors to are from ASTM adopted by state and international building code. That same society has their hands in the testing of myriad other materials, including synthetic lubricants. So, yeah, when I read independant laboratory test results toting the superiority of a product, I beleive it. Is it better than Redline, Mobil 1, royal purpler? Maybe not. But its sure as heck better than the 16 year old conventional that came out thin and black.

Not looking for better performance, just looking to keep my truck nice and original for decades to come.

ilostmypants

if you let the truck warm up in neutral before leaving for a few minuets it warms up the tranny fluid. when the clutch is released in a standard the input shaft is turning and that's moves the oil slinger and that gets the oil moving and will help a bit.

Tubbyfatty

Ive read several threads on here saying GL5 is too slippery and can actually damage the synchros. It also causes bad shifting.

I am currently running Redline gear oil, its a full synthetic and GL4, no problems.

Junkers88

I've heard the same thing a couple of times. I currently run Royal Purple full synthetic (GL4 rated) and I shift just fine no matter what the temp. I wonder if it actually is an issue with the GL5?

vermontoyota

good to know. maybe I'll drain the GL5, put it in the diffs and t case, then get Amsoil's GL4 m/t. too expensive to trash!

Junkers88

I run the same RP synthetic (GL4) in the t-case and front diff (that will change with the new locker since the autos hate anything but dino) but if you're open front and rear you may put your old fluid in the diffs. I don't know about the GL5 in the t-case though.

Windsor

Yeah, what you see above -- GL-4 for the transmission and GL-5 for everything else, due to the synchros in the gearbox. Toyota says you can use GL-5 in the gearbox but you're going to have the exact problems you discovered.

"MTG" is Amsoil's GL-4, fwiw. (MTGQT for quart bottles).

I didn't bother with their "severe gear" oil, I just used their "Synthetic Gear Lube" for the differentials. It is a $3+ per quart difference and I'm not doing serious towing or crawling.

4Crawler

iTrader: (3)

Well there are two things at play with GL-4 vs. GL-5 oils and "suitability" for a given application.

One is that back in the "old days", gear boxes designed for GL-4 oil could actually be damaged by the EP additives in GL-5 oils. GL-5 oils are designed for use on gears with sliding tooth contact, like ring and pinion (hypoid) gears. They need to be extra slippery and resist being sheared apart by the high (extreme) pressure of the sliding gear contact. The problem in the older gear boxes was "yellow metals" like brass and bronze used in bushings and synchros could be chemically attacked by the EP additives in GL-5 oils. GL-4 oils, which are not designed for hypoid gears, lacked these additives and did not attack the yellow metals. In more modern gear boxes, different yellow metal alloys are used to resist GL-5 oil attack and make it OK to use GL-4 or GL-5 oils, in respect to the fact that the GL-5 oil will not damage the inner workings.

But the other side of the coin with GL-4 vs. GL-5 oils is what conditions they are designed to work under. GL-5 oils are extra slippery, this is great when you have a hypoid cut pinion gear spinning against a ring gear with spiral cut teeth. But put that same extra slippery gear oil on a synchro-mesh ring that needs some friction to help it spin it's gear up to speed to make a smooth shift, "extra slippery" is not a desired attribute. GL-4 oils are not as slippery, they are made to work with gears that have non-sliding contact, as GL-5 oils and thus work better with things like synchro rings, they grab better and spin up the gears faster leading to faster, smoother shifts.

In the GL- oil ratings, they evolved over time, GL-1, GL-2, ... GL-5, etc. Each step was done to make a "better" oil for a more demanding application as technology evolved. So a GL-2 oil is "better" than a GL-1 oil, ..., GL-5 is "better" than GL-4. But sometimes "better" is not better depending on the application. It is kind of like cooking oils. For example olive oil and canola oil, they are both vegetable oils, both edible, etc. However, if I had to choose one for putting on a salad with some vinegar, I would go olive oil all the way. But if I were deep frying some french fries, canola oil would be better. So which oil to use depends on what you are using the oil for.

I have run both GL-4 and GL-5 oils in various manual transmissions (Toyotas and VWs), both conventional and synthetic. And I have found that while a synthetic GL-5 oil is better than a conventional GL-5 oil, any GL-4 oil will beat the performance of a GL-5 oil in a manual transmission that uses gear oil. No doubt that a synthetic GL-4 oil will work better than a conventional GL-4 oil. I like the Redline MT-90 or MTL gear oils (MTL better in very cold weather) and that is all I run now in my Toyota and VW. I am sure there are other mfgs. of synthetic GL-4 gear oil, so not saying Redline is the best or better than XXX or YYY brand. It is what is most available in my area (their refinery is less than an hour from my house).
- http://www.4crawler.com/4x4/4R_TechInfo.shtml#Fluids

sb5walker

That's some great info 4Crawler, thanks. Most informative post on the topic that I've run across.

I also found that GL-4 shifted much better in my tranny than GL-5. I use MT-90 and it has worked great.

A while ago I researched gear oils from a cold weather viscosity standpoint and this is what I found:

The main discovery was that none of them flow well in extreme cold, not even the synthetics. But of course the syns do better than the mineral oils, which thicken up terribly due to the wax that they contain. Thick oil will squeeze out of the way and stay out of the way, leaving gear teeth to grind against each other with little to no protection.

For the manual transmission, which needs a GL-4 fluid, the best and most available choices are the full synthetic, ester-based Red Line MT-90 and the full syn PAO-based Amsoil MTG. Both flow well down to -40 degrees, with low temp -40C Brookfield viscosity of 32,000 cP and 44,200 cP respectively. (The max allowable is 150,000 cP but at that viscosity the oil is already failing to lubricate effectively.) Either the Red Line or Amsoil GL-4s would be an excellent choice for cold temps, though the Red Line has an edge over the Amsoil. Summit Racing is a good source for Red Line products.

The differentials require a GL-5 and that's where it gets sticky. These oils, even the synthetic ones, are much thicker at cold temps. The best low-temp performer (for which I could find specs) is Amsoil Severe Gear 75W-90. It has a -40 brookfield of 68,150 cP.

Surprisingly, the ester-based Red Line GL-5 Gear Oil rates 110,000 cP at -40C. Not what I would expect from an ester, but those are the specs.

While most conventional mineral gear oils do terribly below 0 deg F (Coastal is really bad), Valvoline's mineral GL-5 75W-90 Gear Oil performs well with a -40 cP of 106,000. They must have de-waxed it really well. One would expect their full synthetic Synpower GL-5 75W-90 Gear Oil to do even better, but they don't give the spec, hm.

Because the Sta-Lube GL-4 product is a mineral oil and is thicker to start out with (85W-90 instead of 75W-90) I would not use it if winter temps in your area go below 0 deg F. Above that it will probably do fine.

For Canadians, another good choice is Esso GL-5 75W-90 GX Extra with a -40 cP of 90,000.

An intriguing alternative is one of Red Line's lighter weight "Shockproof" gear oils. They have particles of a solid extreme pressure additive suspended in lighter weight, lower viscosity fluids, giving the oil the performance of heavier oils while still flowing very well at lower temps. But the specs don't seem to be available for those, either.

For the transfer case, you can use either a GL-4 or a GL-5. If you live in a region with extreme cold winters, I'd recommend using the same GL-4 that you use in your tranny, since it will flow better than any of the GL-5s. If your winters never go below 0 deg F, a GL-5 would probably give a little more protection.

4Crawler

iTrader: (3)

For really cold use, you can also look at Redline MTL, it is thinner than the MT-90:
- http://www.redlineoil.com/product.aspx?pid=45&pcid=7

I ran it for a while in my Toyota and it worked fine but was a little noiser than the MT-90 I now run. Also that was used in California where the temps were not that low so that probably explained the noise to some degree. I do run MTL in my VW transaxle and it works great there. I can feel a difference in cold shifting between the MTL and MT-90 with the MTL shifting perfectly smooth right off the start, where on very cold morning, the first shift or two with MT-90 feels just a little slower.

Just Learning

wow- i use valvoline 85-140, never noticed any shifting problem, its in my front andd rear diff, in my tranny and xfer case

Matt16

REdline MT90 for me. Shifts really nice in any temperature.

survivorman97

iTrader: (1)

I have recently had a similar experience with my transmission. Thinking that it was a good thinking to do I put in Mobil 75w-90 in. In the summer it was good(ish). But in the winter especially when really cold it just wasn't very easy to get into gear. So after searching for a while on this awesome forum site called "Yotatech" or something jk I found that a lot of guys said they had a lot of luck with gl-4s like MT-90. Anyways I ended up with a BG product called Synchroshift II which was a GL-4 75w-80. Which from as I understand is lighter in cold weather than a 75w-90.And wow what a difference, I changed it during a very cold time and that day a difference in how easy it was to shift could be noticed. So after speaking with the guys from BG on the phone one day just asking some questions I found (please correct me if I am wrong) that mainly because the 75w-90 was THICKER when it was cold out than the 75w-80 its was keeping the synchros from getting to the speeds they needed to. And once it would warn up it would improve. So anyways I guess what I am saying/asking is it the fact that it is a GL-4 or that its a lighter oil (75w-80) in cold temps or a combination of the two that has given me an improved driving experience. Great info by the way 4Crawler.

CoedNaked

You don't want Severe Gear 75w90 in your Manual Transmission. The fluid you should have put in was Amsoil Manual Transmission & Transaxle fluid 75w90. I ran this in my truck when I owned it (the truck in my sig is sold) with Amsoil Severe Gear 75w90 in the Transfer case, & front/rear diffs and it shifted great hot or cold. The Severe Gear is too slippery for your transmission.

mmcpeck

When I got my '92 Xtra Cab, I dropped whatever was in the tranny and put in Redline MT-90. Didn't notice any difference in shifting from what was in there, maybe got a little better, but nothing dramatic.

What I have noticed this winter, (this is the first winter I've had it) is that it shifts GREAT on cold mornings, and actually gets a little worse when it warms up. Shifts as smooth as can be, no notchiness at all, when cold, slides right into all gears. Once it warms up, it gets nothcy and a little tougher to get in gear, not bad, just worse than when cold. I also have a bad/leaking slave cylinder that needs to be changed so, but in any case it shifts like a dream when it's ice cold regardless of the slave.



CoedNaked.....Do you have any pics of that 4.0 VVT-i in the Taco forum? I'd like to see that thing.