# manual tranny oil question



## hans747 (Jul 14, 2005)

I've got a 1996 4cyl witht he 5-speed transmission. Starting back in June, I parked the truck for months. During that time, I changed the transmission and differential oil (valvoline gear oil, what I used last time). I exercised the truck every few weeks. Two weeks ago, i started driving it regularly again. Now I noticed that the transmission is very stiff going into gears 1 through 3. It's very notchy, and i can occaisionally feel the vibration of gears meshing through the shifter. But then yesterday, i took the truck out on the highway for an hour-long drive and the transmission shifted perfectly once I got into city driving. This morning, it's back to driving real stiff.

Any suggestions?


----------



## abmobil (Nov 22, 2004)

If that is valvoline gl5 and it most likely is get it out of there asap!
Nissan trannys have brass synchros and the extreme pressure additives in that oil are not good for those synchros and they do corode them.

That tranny calls for a 90 weight gl4 oil which is hard to come by at local parts stores. Many parts stores have multi rated oils that meet gl3 4 and 5 specs but they are not preferred by these trannys.

It needs a gl4 specific oil. The valovline is a fine product for the diff but its not optimized for a gl4 tranny. I ran the valvoline in my 97 hardbody for awile and had notchy shifts and when it got hot 2nd and 3rd would often grind.
I thought the tranny was having problems but when I did research I found that the oil was probably the problem.

I then tried a multi rated amsoil and they make great products as well but my tranny hated it. I then tried some redline mt90 which is a 75w90 Gl4 only oil and it worked great. I had to go to a specialty store to get it but you can get it online.


----------



## hans747 (Jul 14, 2005)

abmobil said:


> If that is valvoline gl5 and it most likely is get it out of there asap!
> Nissan trannys have brass synchros and the extreme pressure additives in that oil are not good for those synchros and they do corode them.
> 
> That tranny calls for a 90 weight gl4 oil which is hard to come by at local parts stores. Many parts stores have multi rated oils that meet gl3 4 and 5 specs but they are not preferred by these trannys.
> ...


Thank you very much! I will start looking for some GL4 oil immediately.

Eric


----------



## johnnyhammers (Oct 13, 2005)

I've had similar issues with my 97 hardbody 4x4 5spd. when I bought it, it shifted like hell in a sand storm. I saw the GL4 requirement and went with Mobil 1 gear oil (asked if it was ok and the dealer said yes), as I'm a huge fan of the mobil synthetics. This greatly improved my shifting, and even helped my power (just a little) but I still occasionally get a little grind going into 3rd. I still think that the syncro is just shot on this gear, but now I'm a bit curious about trying the redline oil. I once put it in an old Fiat (Bertone) X1/9 that had absolutely no syncros left below fifth gear. The Redline oil made an absolutely huge difference. I still had to learn to heal-and-toe or double clutch on every single shift, but with the Redline gear oil it was now at least possible, and eventually I had smooth seamless shifting; even on fun curvy rural South Carolina roads. Ahh to be seventeen and stupid and fearless again, what fun.


----------



## abmobil (Nov 22, 2004)

At the time I put the gl5 valvoline in my hardbody I was also told by a valvoline oil change center that it would be ok and that gl5 superceded the gl4 requirement.
I figuerd it was similar to how dexronIII superceded dexronII which they dont make anymore. I use M1 in the engine and rear end but the gl5 they make still contains many EP aditives that arent good for our synchros.

Redline MT90 worked great in my 97 hardbody but at the time I put it in the truck had about 120k on it. I put it in my 04 frontier and that tranny had about 2k on it and the shifintg at first was very smooth but became very notchy nad never went back to being smooth unitl I put factory nissan 75w85 GL4 back in there. 

Redline says on there website that trannys are fine to break in on synthetic.
I figuered 2k was plenty but thats the only reason I can think of why it didnt work well since the hardbody has the same tranny.
The next oil im trying is amsoil GL4 75w90. Its a new oil they released just for trannys that call for the GL4 spec.

I also put put MT90 in my friends 95 hardbody 4x4 it it also worked very well in his application.


----------



## johnnyhammers (Oct 13, 2005)

Too bad you've got to touch the damned stuff to change it. Smells too much like Rotten dinosaurs. yuck!


----------



## mitchell35758 (Oct 21, 2005)

abmobil said:


> At the time I put the gl5 valvoline in my hardbody I was also told by a valvoline oil change center that it would be ok and that gl5 superceded the gl4 requirement.
> I figuerd it was similar to how dexronIII superceded dexronII which they dont make anymore. I use M1 in the engine and rear end but the gl5 they make still contains many EP aditives that arent good for our synchros.
> 
> Redline MT90 worked great in my 97 hardbody but at the time I put it in the truck had about 120k on it. I put it in my 04 frontier and that tranny had about 2k on it and the shifintg at first was very smooth but became very notchy nad never went back to being smooth unitl I put factory nissan 75w85 GL4 back in there.
> ...


How often should the tranny oil be changed in a manual. I had a 88 toyota pickup with 120,000 miles on it and replaced the clutch myself and had asked the guy at the auto store if I should do anything else while I was working on it. He said no. My father in-law is a missionary in Africa and he had a 99 nissan frontier. The people over there changed his tranny oil out and the tranny screwed up on him. I never realized that you needed to change the oil in manual transmissions until I joined this forum. Then again, I have only driven manual transmission vehicles for a total of 40,000 miles and all the others have been automatics.


----------



## johnnyhammers (Oct 13, 2005)

sounds like a good question for the shop manual, or even maybe the owners manual.
Do you own one?


----------



## abmobil (Nov 22, 2004)

Although I think it should be changed, alot of people never change it and they dont have problems. My dad bought my 97 hardbody brand new in 97 and put about 90k on it and then I got it when I was 17 in 2001 and I had to start messing with stuff.

The 90k factory fluid worked perfectly fine in that truck but im all about preventitive mantinece so I put GL5 in there not knowing any better and the problems came shortly after.

Drove on the wrong fluid for nearly 30k until I tried redline MT90 and that solved all issues.

I believe the manual reccomends 30k intervals.


----------



## hans747 (Jul 14, 2005)

oh man, I went to the Redline site and no one within 25 miles of my house carries the stuff. Maybe I'll look into the Mobil1 option or see what the dealer sells.


----------



## mitchell35758 (Oct 21, 2005)

johnnyhammers said:


> sounds like a good question for the shop manual, or even maybe the owners manual.
> Do you own one?


Owner's Manual? What, you mean that new vehicles come with owner's manuals? Well gosh darn, you know, you learn something new everyday. Thanks johnnyhammers, oh wont you please be on my buddies list? :loser:


----------



## mitchell35758 (Oct 21, 2005)

abmobil said:


> Although I think it should be changed, alot of people never change it and they dont have problems. My dad bought my 97 hardbody brand new in 97 and put about 90k on it and then I got it when I was 17 in 2001 and I had to start messing with stuff.
> 
> The 90k factory fluid worked perfectly fine in that truck but im all about preventitive mantinece so I put GL5 in there not knowing any better and the problems came shortly after.
> 
> ...


I know I did not check the manual first before posting my question, and I still haven't. Thanks for posting the recomendation.


----------



## johnnyhammers (Oct 13, 2005)

The shop manual is a common rant of mine. I'm always seeing guys just trying to figure stuff out on their own; "kuz they smart enuff an'don't need no stupid book to tell 'em how to fix they daddys truck". Though I do find this way more in the Ford/Chevy/Dodge crowd. Imports owners just have higher breeding I guess.  

As for new cars and owners manuals, I guess I wouldn't know. I've always bought my own used. My 97 is by far the newest vehicle I've ever owned. Hell, 1990 is still new to me.


----------



## mitchell35758 (Oct 21, 2005)

johnnyhammers said:


> The shop manual is a common rant of mine. I'm always seeing guys just trying to figure stuff out on their own; "kuz they smart enuff an'don't need no stupid book to tell 'em how to fix they daddys truck". Though I do find this way more in the Ford/Chevy/Dodge crowd. Imports owners just have higher breeding I guess.
> 
> As for new cars and owners manuals, I guess I wouldn't know. I've always bought my own used. My 97 is by far the newest vehicle I've ever owned. Hell, 1990 is still new to me.


Hey, I was joking about the owner's manual thing being in the truck. The used vehicles that I have owned all had them, mainly I guess because the owners were responsible. My frontier was bought new and as all new vehicles do, it came with the manual. 

I was just reading the forum and the question poped into my head. Figured I would just ask before I forgot.


----------



## hans747 (Jul 14, 2005)

Hey, what type of Mobil1 did you use in your truck? i looked at their site and i can only find GL5 oils.


----------



## Cusser (Apr 16, 2004)

Mitchell - I always drain and replace manual transmission oil and differential oil every 30-35K miles on my vehicles, and use whatever is detailed in the owner's manual. I've seen some manual transmissions that state 30W engine oil (my old Chevy Luv) and others that actually take ATF !!! There are inexpensive pump heads which screw onto transmission oil containers so you can pump in the oil through the side plug; pump in slowly, until it just starts to verflow, then replace the side plug. I'll assume you've already replaced the bottom drain plug(s) after draining but before beginning refilling.


----------



## Bror Jace (Apr 26, 2003)

Lots of lies out there in oil land. No, GL5 did NOT replace GL4. GL5-only rated oils shoulf not be used in syncromesh trannies that specify GL4.

Lots of trannies survive pretty severe neglect ... others seem to act up even when meticulously cared for. 

I always maintain these things to the hilt. Just be sure to use a top quality oil of the correct weight. My #1 pick in a GL4 would be Specialty Formulations MTL-R:

http://www.specialtyformulations.com/index_files/Page675.htm

Red Line MT-90 would also be a great choice and is available at places like oilshop.com

I've heard the new GL4 Amsoil lubes are good, but have not tried them.


----------



## mitchell35758 (Oct 21, 2005)

Cusser said:


> Mitchell - I always drain and replace manual transmission oil and differential oil every 30-35K miles on my vehicles, and use whatever is detailed in the owner's manual. I've seen some manual transmissions that state 30W engine oil (my old Chevy Luv) and others that actually take ATF !!! There are inexpensive pump heads which screw onto transmission oil containers so you can pump in the oil through the side plug; pump in slowly, until it just starts to verflow, then replace the side plug. I'll assume you've already replaced the bottom drain plug(s) after draining but before beginning refilling.


I am not quite at the point were I need to replace the oil yet, but what you have posted is helpful and I will refer to it when it comes time. Thanks for the info.


----------



## NismoFrontin' (Oct 4, 2005)

I just did a tranny and diff fluid change on my truck. I put 75w90 Mobil 1 synthetic in the tranny that was GL5, and Valvoline 80w90 in the diff (because Mobil 1 doesn't make 80w90). Seems to shift a bit smoother now, but I just wanted to know for sure:

Is the Mobile 1 GL5 ok for our tranny's? Or did I just waste 25 bucks and an hour of my time?

Also, what's a good way of telling whether a synchro went out or not?


----------



## johnnyhammers (Oct 13, 2005)

In general GL5 is not acceptable in these trannies, but I did some research when I needed to change mine and the Mobil 1 guys say it's ok, as do the guys at the local Nissan dealer. I had the same experience, a little smoother and just a pinch more power than before the Mobil1. 
Syncro's are whole other ball of wax, I'd try a search of the threads and I bet you'll turn up a very good conversation or two. I will say this. Bad syncro's just mean you have to have better shifts, but you can totally drive a tranny with absolutely no syncro's left in it, you just have to be kind to the gears. try "double clutching" and "heel and toe", These are basic performance driving techniques and they're made for shifting faster than the syncromesh can deal with, so at regular speeds they can eliminate the need for syncro's in everything but first gear (and you can even live quite happily without that one too). 
Good luck!


----------



## Bill3508 (Nov 1, 2005)

I just changed mine as well in my 99 KC 4wd. I was having the notchy rough shifting problem also, sometimes its nice, other times its rough. I originally purchased Mobil 1 gear oil but called Mobil 1 before I put it in because there was such debate about what to use. Mobil 1 said not to use that in my manual trans. I ended up using MT90 but it doesn't work any better. I think some people are using MTL, susposedly lighter and having good results. I think next time I will just go get the factory stuff.

Bill3508


----------



## johnnyhammers (Oct 13, 2005)

Bill3508 said:


> I originally purchased Mobil 1 gear oil but called Mobil 1 before I put it in because there was such debate about what to use. Mobil 1 said not to use that in my manual trans. I ended up using MT90 but it doesn't work any better. I think next time I will just go get the factory stuff.
> 
> Bill3508


Funny how we can both call the same company with the same question and get different answers. I must have gotten the salesman, while you got the scientist. I'd have rather gotten a definitive no than a questionable yes "it should be just fine".


----------



## NismoFrontin' (Oct 4, 2005)

johnnyhammers said:


> Funny how we can both call the same company with the same question and get different answers. I must have gotten the salesman, while you got the scientist. I'd have rather gotten a definitive no than a questionable yes "it should be just fine".


I called the guys at Nissan an talked to them about it. They said that not only was GL5 okay to put in, but also that they use GL5 when servicing peoples' transmissions. I hope they're right.


----------



## abmobil (Nov 22, 2004)

They are idots! Gl5 is not for these transmissions!!!!!!!
Gl5 contains many Extreme pressure additives that ruin synchos.
I dont doubt that they put it in customers cars.
They put it in mine even though they told me they didnt touch the oil.


----------



## Bror Jace (Apr 26, 2003)

Generally, GL5 oils offer more protection for strictly steel parts than a GL4 ... but they do so with sulfurized compounds that can eat soft metals (copper, brass, bronze, etc ...).

Some gear oils offer a dual GL4/GL5 rating. This means they use the newest high-performance addtives (such as some moly, boron, etc ...) but are NOT corrosive to soft metals. The best of both worlds! 

Coastal makes gear oils you can get at AutoZone which have multiple gear oil ratings such as GL3, GL4 & GL5.

Red Line has some non-corrosive gear oils as does Specialty Formulations.


----------



## NismoFrontin' (Oct 4, 2005)

Hey, I appreciate the info everyone. I'm taking that GL5 crap out of my tranny tomorrow. A $25 loss is better than losing all of my synchro's. Sounds like Redline MT90 is a good choice, I'm gonna try it.


----------



## hans747 (Jul 14, 2005)

NismoFrontin' said:


> Hey, I appreciate the info everyone. I'm taking that GL5 crap out of my tranny tomorrow. A $25 loss is better than losing all of my synchro's. Sounds like Redline MT90 is a good choice, I'm gonna try it.


Wish there was somewhere close to me that sold MT-90. Everywhere here has it as a "special order only" item. Turns out Penzoil also offers a Synthetic GL4 fluid. http://www.pennzoil.com/products/gear_oil/syn_gear7590.html Maybe that wilol be easier to find.


----------



## jerryp58 (Jan 6, 2005)

hans747 said:


> Wish there was somewhere close to me that sold MT-90. Everywhere here has it as a "special order only" item. Turns out Penzoil also offers a Synthetic GL4 fluid. http://www.pennzoil.com/products/gear_oil/syn_gear7590.html Maybe that wilol be easier to find.


FWIW, I went mail order with my Amsoil and it took about two days to arrive (~$5 shipping). I've only had it in there for about 500 miles, but I've been happy so far. I haven't noticed any difference really, but I haven't had any problems (knock wood) and I hope it's running cooler and smoother. BTW, a recent episode of TrucksTV (maybe it was Extreme 4x4) put synthetics in the drivetrain components of a 4x4 and noticed a reduction in temperature (they shot the housings with a temp gun) and reduced torque requirements (I think to achieve/maintain a set speed).


----------



## LIPA (Nov 23, 2005)

I'm going to change my tranny fluid this weekend and also having a hard time finding 75w-90 gl-4, several small parts stores have pennzoil syth., 75w-90 gl-4 and all are around $18.00 a quart which is way too much. Either we don't know much about gl-5 yet and should probaly be safe since my nissan dealer also stated that they use gl-5 for manuel trannys and everyone I ask (auto parts store guys) will say its better and newer than gl-4, if this is not true than there's going to be alot of nissans with bad transmissions out there. Think about it there must be thousands of nissans that have gl-5 in the trannys which the owner doesn't have a clue or a new buyer and still perform like new, I'm not saying use gl-5, but is this stuff really that bad. I myself will order online, RedLine MT-90, any thoughts would be appreciated.

2001 frontier 5spd, kc, 4x4


----------



## Bror Jace (Apr 26, 2003)

*LIPA*: _" ... my Nissan dealer also stated that they use GL-5 for manual trannys"_ 

I have never gotten excellent lubrication advice from dealerships. Older trannies are fine with GL-5.... but many newer syncromesh boxes are _not_ and if it says GL-4, you better not be using an old GL-5.

_" ... and everyone I ask (auto parts store guys) will say its better and newer than GL-4."_ 

And they are dead wrong. It's NOT like motor oils where every new classification is stricter and (generally) an improvement which is backwards-compatible. Of course, if you know just a little bit about cars, you might think this.  

Oh, and auto parts guys as a breed know even less about lubricants than dealership guys. I remember when most Hondas and Fords started asking for 5W-20 motor oil. I went into an Advance Auto Parts and no one in the store knew what I was talking about.  

_ ... if this is not true than there's going to be alot of Nissans with bad transmissions out there."_

Yep. Thankfully, I don't buy used cars. 

Oh, and thank you for using the search feature and finding this old thread instead of merely creating a new one for your question.


----------



## hans747 (Jul 14, 2005)

Unfortunately, the only affordable GL4 synthetice I've been able to find is online. Check out Amsoil.com. Also, I was watching Trucks on Spike a few days ago, and they were saying that Royal Purple makes a GL5 that will work with a GL4. They actually said the words "not corrosive." That's a pretty strong claim, and I would assume that an oil company (who knows their products) wouldn't go out on that limb without being sure of it first.


----------



## Bror Jace (Apr 26, 2003)

_" ... they were saying that Royal Purple makes a GL5 that will work with a GL4. They actually said the words "not corrosive." That's a pretty strong claim, and I would assume that an oil company (who knows their products) wouldn't go out on that limb without being sure of it first."_

Gear oils _can_ be dual certified as GL4 _and_ GL5. Specialty Formulations dual certify many of their's ... as does Motul (I think).

So if RP's gear oil meets both criteria, why not offer dual certification?

I'd feel better if it says GL4 right on the bottle.

Between the Amsoil dealers, Specialtyformulations.com and myoilshop.com, the tried-and-true GL4s are not all that difficult to find these days.


----------



## hans747 (Jul 14, 2005)

Bror Jace said:


> _" ... they were saying that Royal Purple makes a GL5 that will work with a GL4. They actually said the words "not corrosive." That's a pretty strong claim, and I would assume that an oil company (who knows their products) wouldn't go out on that limb without being sure of it first."_
> 
> Gear oils _can_ be dual certified as GL4 _and_ GL5. Specialty Formulations dual certify many of their's ... as does Motul (I think).
> 
> ...


I wish I could say the same. I live in what some would call a city, and the nearest Amsoil guy I can find is 60 miles away. And none of the local parts stores carry GL4 either. Then again, I never called the Toyota dealer. They might have it...

As for the Royal Purple, I don't know if it says it on the bottle because I've never held it in my hand, but their web site doesn't mince words about the GL4 capabilities. Check out the FAQ link on this page.

http://www.royalpurple.com/prodsa/mgeara.html


----------



## Bror Jace (Apr 26, 2003)

*hans747*, based on what they say on their website, yeah, I'd consider using that in a manual tranny calling for a 75W-90 GL-4 without worrying about any soft-metal degradation. The only thing you might not get is a carefully tailored coefficient of friction designed to ideally compatible with synchronizers ... but some trannies aren't as picky about this as others.

There's even more evidence Max Gear's safe in the "Packaging & Properties" tab. One thing that's puzzling though is that they sell a 75W-90, 80W-90 and a straight 90. A proper synthetic 75W-90 should fill all three roles. Odd.

I'm still not a Royal Purple fan for a number of reasons ... although others have decent luck with their stuff. I won't 'warn' against using it although I trust other brands a lot more.

As for availability, you can buy RP locally? I know I can't. I know that when I go to buy high performance lubricants, I'll be going mail order. It's just a matter of deciding between the many brands I like. 

_"I never called the Toyota dealer. They might have it..."_

I'd never call a dealership for parts I can get elsewhere ... that's just asking to be raped. I've seen some charge up to $18 or more per quart of "synthetic" (whatever that word means these days.  ) gear oil. I can get Red Line, Amsoil or Specialty Formulations for less than that via mail order even after S&H is added in ... and I'm sure those name brands are equal or better stuff.


----------



## mitchell35758 (Oct 21, 2005)

Bror Jace said:


> Lots of lies out there in oil land. No, GL5 did NOT replace GL4. GL5-only rated oils shoulf not be used in syncromesh trannies that specify GL4.
> 
> Lots of trannies survive pretty severe neglect ... others seem to act up even when meticulously cared for.
> 
> ...


Where did you hear about them, and was it a reliable source? I am getting closer to time for a change and wanted some good advice on the tranny fluid. 
I know you already posted your answer to this, but I will ask again because some time has passed and I know you get a lot of info from BITOG, what is your #1 RECOMENDATION AS OF RIGHT NOW? And I know it has been posted a hundred times, but am asking once more TO BE DEAD SURE, GL4 is the only RIGHT one to use, right?

thanks

I know that link was posted a while ago, but it appears it is no longer good. Any new ones for this stuff? Just being lazy but I will check for my self later. Thanks again


----------



## MrFancypants (Nov 18, 2005)

Stay away from GL5 only (e.g. Mobil 1) gear oil unless you want to wear out your synchros. Good GL4's include RP SyncroMax 75W90, Redline MT90, etc. You can buy Royal Purple gear oil at Napa. For a tranny that sees a lot of abuse, Redline Heavy Shockproof is awesome stuff. Ive run all of the above oils in SR20 5 speed transmissions and they did a fantastic job.


- Greg -


----------



## mitchell35758 (Oct 21, 2005)

MrFancypants said:


> Stay away from GL5 only (e.g. Mobil 1) gear oil unless you want to wear out your synchros. Good GL4's include RP SyncroMax 75W90, Redline MT90, etc. You can buy Royal Purple gear oil at Napa. For a tranny that sees a lot of abuse, Redline Heavy Shockproof is awesome stuff. Ive run all of the above oils in SR20 5 speed transmissions and they did a fantastic job.
> 
> 
> - Greg -


Thats what I had gathered so far from this but wanted to ask one more time. Thanks Greg

Anyone else as far as which full syn brand is the favorite?


----------



## Bror Jace (Apr 26, 2003)

*mitchell35758*, my recommendation is still the Specialty Formulations oils ... MTL-P (75W-85) and MTL-R (75W-90) depending what your tranny calls for (I think it's 75W-90 for all Nissan trucks).

Both are dual-rated GL4/GL5. This means they have the extra wear protection of a GL-5 ... but are non-corrosive (required for GL-4).

I've got about a year and 8,000 miles on the MTL-P in my SpecV 6-speed.


----------



## mitchell35758 (Oct 21, 2005)

Bror Jace said:


> *mitchell35758*, my recommendation is still the Specialty Formulations oils ... MTL-P (75W-85) and MTL-R (75W-90) depending what your tranny calls for (I think it's 75W-90 for all Nissan trucks).
> 
> Both are dual-rated GL4/GL5. This means they have the extra wear protection of a GL-5 ... but are non-corrosive (required for GL-4).
> 
> I've got about a year and 8,000 miles on the MTL-P in my SpecV 6-speed.


thanks Bror Jace

so what I gather so far is that the 
specialty formulations MTL-P (because he seems to be on top of things in oil research)
Amsoil
Redline
are the favorites. 

I'm torn between all three right now. It seems like I hear alot about the redline stuff, the Amsoil has kinda new stuff out, and Bror Jace ("the BITOGian") favors specialty forumlas. 

Does anyone else have any experience with the specialty formulas?
I've never heard of them before until a couple of days ago here on nissanforums.com. But I will be checking BITOG and other websites and just wanted to get some more positive feedback about the stuff from any of you that use it.


----------



## Bror Jace (Apr 26, 2003)

*mitchell35758*, I see above that you asked where I had heard of Specialty Formulations. I apologize for not having responded to this in my previous post.

Specialty Formulations is the small company founded by *MolaKule* who’s a regular contributor to the BITOG site (He joined right after I did in 2002). He’s a chemist and a physicist who’s done consulting work for the aerospace industry. In his spare time he teaches physics classes and works with a local aircraft club … and most recently, he started “Specialty Formulations” serving eccentric automotive extremists like myself … as well as a few race teams (Note to self: ask him which ones).

His gear oils are ester-heavy, 100% synthetic formulations which have some of the heaviest additive packages in the industry (heavier than the Red Line MTL/MT-90 twins).

I use MTL-P in my SpecV’s notoriously picky 6-speed and have gone to great lengths to talk up this particular fluid in this particular application, spreading the word here … as well as other places SpecVers hang out. I used the factory fluid as well as a mix of Red Line MTL and MT-90 (trying to find a 'misddle' weight). MTL-P was easily the best of the three ... both in the cold as well as warm weather.

The same fluid is also a replacement for OEM Honda MTF … but most goofs on some of the Honda boards I used to frequent (had a Civic until ’03) are in love with the too-thin GM syncromesh fluids and won’t listen … until they suffer massive catastrophic failures in a couple years.  

Applications calling for 75W-90 tend to be less picky so I don’t consider MTL-R a ‘must’. But it’s still what I’d run if any of my vehicles called for it. Soobie WRXs seem to like it according to a few WRXen that have chimed in on BITOG.

Since you’re in ‘Bama, I wouldn’t consider anything lighter than what’s specified in your manual. For my friends way up north in Canuckistan, They can go slightly thinner because their trannies routinely see cooler … and downright frigid … temperatures. 90F+ days are few throughout the year.

Amsoil dealers used to recommend their various motor oils and GL-5 gear oils for synchronized tranny applications. They might have been “OK” but I highly doubt they were ideal. Their foray into dedicated synchromesh fluids is fairly recent. I’d refer you to *Pablo* for specific applications except that you should probably be patronizing the Amsoil dealers who sponsor this site.


----------

