has anyone tried any amsoil in their tranny??

 

My '89 paper FSM recommends 75w90 GL-4 or GL-5. I've used GL-5 for 25 years in Toyota manual transmissions and have never had a problem. An oil change place I worked at years ago only had GL-5 and that's what we put in all manual transmissions calling for gear oil. (Some actually use ATF and SAABs used to use 10w30 motor oil). Using Royal Purple in the trans right now in Anchorage and it's been great.

 

Not yet, that's coming up soon, though.

I had my (W56) transmission rebuilt last year, so when the 1yr anniversary came up I wanted to swap the oil with Amsoil. I checked with the shop that did the rebuilt it and he gave me the green light.

I already have the (GL-4) oil purchased, so it's just a matter of "getting it done".

 

It's possible for a manufacturer to get it wrong with recommendations.

I'm aware that SOME GL-5s work fine. But that was not my experience in my 89 4wd V6 truck. From the time I bought it in 95, I was experiencing extremely hard shifting. I assumed the synchros had nearly completely worn out. Soon after buying it, I replaced all the gear oil, but used GL-5 (I don't remember which one) in everything. After several years of continuing hard shifting, I either read or heard from someone about GL-4 working better in the manual trannys and I gave it a try. NIGHT and DAY. The transmission immediately began shifting smoothly, for the first time since I owned it. It finally worked as a transmission should. Before I could NEVER shift into first if moving even slightly, and even downshifting to second was troublesome, but with the GL-4 it went into first fairly easily and downshifted into second like butta.

What makes a GL-5 a GL-5 is the addition of EP (extreme pressure) additives. They are needed to protect the differential gears which experience a lot of sliding force. I guess depending on how much or what type of these are used in a GL-5, it can cause the synchros in the tranny to slip too much, leading to hard shifting. This apparently is not the case with all GL-5s, but it most assuredly is the case with SOME of them.

 

Which GL-5 fluids would you recommend? Anything synthetic?

 

Do you have an owners manual or factory service manual for your pickup? If you do, why would not you just follow the factory spec for trans lube? You know, Toyota parts are the "gold standard" for replacement parts, and I suspect that their recommendations are the same for periodic service and maintenance. GL-5 is specified for limited-slip differentials. It has additional additives required for those applications. GL-4 is fine for transmissions, and is probably what your manual specs for the transmission.

Around here, and in California, I have to go to a hardware store for GL-4. All the parts stores and WallyWorld have is GL-5. My roto-tiller specs GL-4 because one of the drive gears is bronze alloy. It is alleged that GL-5 has/had additives that attack "yellow metals" (brass/bronze/etc alloys). Some synchromesh transmissions have some "yellow metal" components.

By the way; reports of "I've been using xyz for years and no problems" are anecdotal information; just like "I've smoked a pack a day for years, and I'm just fine..."

My $0.02

My $0.02

 

jj'89 no matter if you use gl-5 or gl-4 in limited slip you still need friction modifier or it won't work smoothly. I use lucus 85/ 140 in my transmision transfer case and both diffs and have never had any problems at 300 thousand miles .

 

You pay premium for Lucas products? Good for you; especially good for Lucas company. Your anecdote. Here's mine: 1965 Chevelle El Camino. At 90,000 miles or so in 1975, the limited-slip differential (I believe that GM called theirs "Positraction") began winding-up and popping after a 90 degree turn from a stop. I replaced the factory fill with Sta-Lube GL-5 90 wt. Been fine ever since... By the way, a friction modifier is one component of the mixture of chemical compounds that constitute GL-5 (and GL-4) gear lube(s)

My $0.02

 

FWIW, my (Toyota) owner's manual and the FSM both say "GL-4 or GL-5" for all of the driveline goodies.

 

GL-5 is recommended for all differentials, not just limited-slip.

Mostly correct. You need LSD additive for clutch-style LSD differentials. The "helical gear"-type (Torsen is one example) do not require additives.

 

I've been running Redline MT90 in mine for the past 14K miles and no issues.

 

I just checked mine and it also says GL4 or GL5. I was lazy/afraid to check it because there's a ton of receipts in the folder with the manual and it's a mess.

 

Sorry, Duperman, I missed this. I do like synthetic gear oils, for two reasons. One, synthetic oils resist viscosity breakdown much longer than petroleum oils, and that's important in the drivetrain components where we don't change them all that often. The other reason is cold flow performance. It turns out that none of the GL-5s flow well in cold weather, but most of the the mineral oils thicken up especially badly, in even moderate cold. The synthetics do better. The best cold performer is Amsoil's excellent Severe Gear 75W-90, but Valvoline's oils have very good cold flow, and I've been using Synpower 75W-90 GL-5 in my transfer case & diffs for several years with good results. It's considerably cheaper than the Amsoil but still an excellent oil.

This post has more info on gear oil cold flow performance: https://www.yotatech.com/forums/f116.../#post51338384

 

you can use gl 4 or gl 5 it does not matter in toyota transmissions

 

I know, reviving an old thread but I figured it was better then starting a new one I have a manual 94 22re 4wd giving me some shifting issues which coincidently occurred immediately after I changed the transmission fluid and clutch fluid. It is real rough shifting down into 2nd unless the rpms are super low(coming into 2nd around 2rpms) and shifting up around 4-5 rpms it feels a bit notchy. For the tranny I used Royal Purple and for the clutch I used Toyota dot 3 fluid. I bled the clutch and double checked the tranny oil with little to no improvement. My only thought is the change in oil, but I have no idea what was in before to use as a comparison. One other side note is that I also replaced the clutch fork boot....so maybe something happened when I did that? Any ideas would be great!